Dissertations / Theses: 'Complex antioxidant'

1

Liu, Zheng-Xian. "Antioxidant activity of Mn-salophen complex and its effects on antioxidant enzymes in Escherichia coli." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40046.

Full text

Abstract:

Mn-salophen complex with superoxide-scavenging activity was prepared from manganese(III) acetate dihydrate and salophen in ethanol. Visible absorption spectrum of the red-brown solution exhibited a broad absorption band at 430 - 450 nm with two shoulders between 500 and 600 nm which were absent with either salophen or manganic acetate alone. Titration of salophen with manganese(III) was consistent with a 1:1 Mn to salophen stoichiometry of the complex based on changes in the absorbance at 500 nm or of superoxide scavenging activity. The SOD-like activity of the complex in the xanthine-xanthine oxidase/cytochrome c assay was 1450 units/mg salophen. The SOD activity of the complex was suppressed 50% in the presence of EDTA (1 mM), but was not altered in the presence of bovine serum albumin (1 mg/ml) or crude protein extract of E. coli QC779 sodA sodB (1 mg/ml). E. coli QC779 sodA sodB grew scantily after an 8 hour lag phase in aerobic M63 glucose minimal medium.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

2

Kim, Youngmok. "Factors influencing antioxidant phytochemical stability of teas." [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Killmukhametova, Yu H. "Concentration of general immune complexes in experimental animals with and without the local treatment of gingivitis with the complex antioxidant therapy." Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/17832.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Bottari, Nathieli Bianchin. "RESVERATROL LIVRE E EM COMPLEXO DE INCLUSÃO ASSOCIADO AO SULFAMETOXAZOL-TRIMETROPIM EMCAMUNDONGOS INFECTADOS EXPERIMENTALMENTE COM Toxoplasma gondii." Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/11249.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The Toxoplasma gondii is a protozoan of great clinical importance can cause functional and biochemical changes in the host cells mainly in the central nervous system. These changes are usually associated with the inflammatory response to tissue damage and cell oxidation in immunocompetent hosts. T. gondii infection stimulate the production of high levels of cytokines such as IL-12 and IFN-γ by cells of the immune system, consisting of a main point in parasite control and disease resistance. As a potent antioxidant, resveratrol has become an important research subject due to its antioxidant and anti-inflammatory properties. However, the mechanism by which resveratrol exerts its effects are hampered by the low solubility and bioavailability. Accordingly, one way to improve the bioavailability of resveratrol is to associate with inclusion complexes. Thus, this study aimed to investigate the benefits of resveratrol associated with sulfamethoxazole-trimethoprim (ST) in the treatment of experimentally infected mice with T. gondii. For the study, 60 mice were divided into two groups: non-infected (n = 24) and infected with T. gondii (n = 36). The two groups were divided into subgroups and treated with resveratrol (free and inclusion complex 2-hydroxypropyl-β-cyclodextrin) isolated and associated with ST. The groups A to D composed by healthy mice and groups E to J consisting of animals infected by T. gondii (VEG strain). The treatment started 20 days post-infection for 10 consecutive days with oral doses of 0.5 mg kg-1 of ST (groups B and F), 100 mg kg-1 of free resveratrol (groups C and G) and inclusion complex of resveratrol (inclusion complex containing resveratrol) (groups D and H), as well as with an association of both drugs (groups I and J). Groups A and E were used as control, untreated. Behavioral tests (memory, anxiety and locomotion) were performed after treatment. Blood samples, liver and brain fragments were collected to evaluate the cytokine profile, pathological changes, brain cysts counts, as well as oxidant/antioxidant profile. Infected animals showed behavioral changes such as anxiety and memory loss. The combination ST and resveratrol was able to restore time latência in passive avoidance task. A reduction of the number of brain cyst was observed on animals treated with the combination of drugs. Infected animals show an increase in pro-inflammatory cytokines and reduction of anti-inflammatory cytokine (IL-10), as well as increased protein oxidation in liver and brain tissue. The combination of resveratrol and ST with free inclusion complex in increased the total antioxidant capacity (TAC) and ferric reducing antioxidant power (FRAP) levels in liver and brain that can be interpreted by the protective effect of resveratrol. In addition, resveratrol in inclusion complex form when combined with ST improved therapeutic effect of ST reducing oxidative damage in liver and brain, reducing the number of cysts in the treatment of mice infected with T. gondii. Therefore, it is possible to suggest that the ST with resveratrol on treatment of infected mice can exerts a protective effect on host cells. The resveratrol in inclusion complex form was the best treatment option, for controlled tissue and serum immune responses, as well as oxidative stress in mice infected with T. gondii.
O Toxoplasma gondii é um protozoário de grande importância clínica capaz de ocasionar alterações bioquímicas e funcionais nas células do hospedeiro, principalmente no sistema nervoso central. Essas alterações, geralmente estão associadas à resposta inflamatória com danos teciduais e oxidação celular em hospedeiros imunocompetentes. A infecção por T. gondii estimula a produção de altos níveis de citocinas, tais como IL-12 e IFN-γ, pelas células do sistema imunológico, consistindo em um ponto principal no controle do parasito e resistência à doença. Como um potente antioxidante, o resveratrol tem se tornado um importante alvo de pesquisas graças a suas propriedades antioxidantes e anti-inflamatórias. No entanto, os mecanismos pelo qual o resveratrol exerce seu efeito são prejudicados pela baixa solubilidade e biodisponibilidade. Nesse sentido, uma forma de melhorar a biodisponibilidade do resveratrol é associá-lo a um complexo de inclusão. Desta maneira, os objetivos deste estudo foram investigar os benefícios do resveratrol associado a sulfamethoxazol-trimetropin (ST) no tratamento de camundongos infectados experimentalmente com T. gondii. Para o estudo, 60 camundongos foram divididos em dois grupos: não-infectados (n=24) e infectados com T.gondii (n=36). Os dois grupos foram subdivididos em subgrupos (n= 10) e tratados com resveratrol (livre e em complexo de inclusão 2- hidroxipropil-β-ciclodextrina) isolado e associado com ST. Os grupos A-D foram compostos por animais saudáveis; grupos E-J consistiram de animais infectados por T. gondii (cepa VEG). O tratamento foi iniciado 20 dias após a infecção e manteve-se por 10 dias consecutivos nas doses orais de 0.5 mg kg-1 de ST (grupos B e F), 100 mg kg-1 de resveratrol livre (grupos C e G) e na forma de complexo de inclusão (grupos D e H), bem como na associação de ambas drogas (grupos I e J). Grupos A e E foram usados como controles, não tratados. Testes comportamentais (memória, ansiedade e locomoção) foram avaliados após o tratamento. Amostras de sangue, fragmentos de fígado e cérebro foram coletados a fim de avaliar os níveis de citocinas, alterações histopatológicas, contagem de cistos cerebrais, como também perfil oxidativo/antioxidante. Animais infectados com T. gondii apresentaram alterações comportamentais como ansiedade e perda de memória. A combinação com ST e resveratrol foi capaz de restaurar o tempo de latência no teste de esquiva inibitória. Uma redução na contagem de cistos foi observada nos animais tratados com a associação de drogas assim como redução das lesões teciduais. Animais infectados apresentam aumento de citocinas pró-inflamatórias e redução da citocina anti-inflamatória (IL-10), assim como maior oxidação proteica em tecido hepático e cerebral. A combinação de ST com resveratrol livre e em complexo de inclusão aumentou os a capacidade antioxidante total (TAC) e os produtos de redução férrica (FRAP) em fígado e cérebro que pode ser interpretado pelo efeito protetor do resveratrol. Além disso, o resveratrol na forma de complexo de inclusão quando combinado à ST melhorou o efeito terapêutico da ST reduzindo os danos oxidativos, lesões hepáticas e número de cistos cerebrais no tratamento de camundongos infectados com T. gondii. Portanto, é possível sugerir que a combinação de ST com resveratrol em camundongos infectados parece exercer um efeito protetor nas células hospedeiras. O resveratrol na forma de complexo de inclusão foi a melhor opção terapêutica, pois controlou as respostas imunológicas séricas e teciduais, assim como o estresse oxidativo em camundongos infectados com T. gondii.

APA, Harvard, Vancouver, ISO, and other styles

5

Hyardin, Aude. "Étude de la fonctionnalité alimentaire de plats industriels." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL038N/document.

Full text

Abstract:

Consommateurs, chercheurs et industriels cherchent de plus en plus à associer à la valeur nutritionnelle des aliments, un effet bénéfique pour la santé. Les aliments caractérisés par des pouvoirs antioxydants élevés semblent correspondre à cette demande. En effet, plusieurs travaux mentionnent les bénéfices santé de ces aliments. Pour répondre à cette demande les industriels mettent en avant ce critère. La fonctionnalité alimentaire, aux bénéfices prometteurs pour la santé publique, reste un concept néanmoins complexe dans la pratique. Ce travail met l’accent sur le fait que les propriétés fonctionnelles d’un aliment ne sont pas directement liées à la composition en ingrédients. L’évaluation du pouvoir antioxydant d'un aliment est dans la plupart des cas réalisée à partir des valeurs des différents ingrédients avant formulation et mise en œuvre des procédés. Pourtant, plusieurs phénomènes sont susceptibles de modifier le pouvoir antioxydant lors de la durée de vie d'un produit alimentaire. D’un point de vue industriel, il est nécessaire de développer une méthode de prédiction de cette activité. Les objectifs de ce travail étaient d’adapter une méthode reproductible et facile à réaliser de quantification du pouvoir antioxydant sur des aliments complexes et de comparer cet index d'un ensemble de produits contenant une large gamme de matières premières. Enfin, a été discuté l’intérêt que représente, dans le domaine des propriétés anti oxydantes, la quantification de l’index créé. Au moment où les industriels vont être amenés à proposer des allégations liées à l’effet bénéfique de l’aliment choisi parmi un échantillon de plus en plus ample
Consumers, researchers and industrialists try more and more to associate with the nutritional value of food, a beneficial effect for the health. Food characterized by high antioxidant powers seems to correspond to this demand. From an industrial point of view, it is necessary to develop methods of predicting this antioxidant capacity. The objectives of this work were to adapt a method reproducible and easy to realize of quantification of the antioxidant power on complex food and to compare this index of a set of products containing a wide range of raw materials. Until now, it has been considered that the use of raw materials characterized by a high antioxidant capacity also leads to a preparation with a high antioxidant activity. We evaluated many of the factors affecting the antioxidant activity of convenience foods (phenol content, effects of formulation, culinary reheating, and preservation) and to provide data on convenience foods consumed by the French population. The total antioxidant capacity of the ethanolic extracts was evaluated by the method of the equivalent Trolox (TEAC) using the radical cation ABTS•+. The concentration of the total phenolic compounds of the same extracts was determined by the Folin-Ciocalteu method. The results show that the food matrix is an important factor for the modulation of activities of antioxidants. A standardised testing protocol for evaluating antioxidative effects is necessary. Then, we discussed the interest of an index, as the industrialists are going to be brought to claim to the beneficial effect of the food chosen among a more and more ample sample

APA, Harvard, Vancouver, ISO, and other styles

6

Cottrell, Catherine E. "Genetic variation and complex disease: the examination of an X-linked disorder and a multifactorial disease." The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1196182829.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Koontz, John L. "Controlled Release of Natural Antioxidants from Polymer Food Packaging by Molecular Encapsulation with Cyclodextrins." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26757.

Full text

Abstract:

Synthetic antioxidants have traditionally been added directly to food products in a single initial dose to protect against oxidation of lipids and generation of free radicals. Natural antioxidants have been shown to undergo loss of activity and become prooxidants at high concentrations; therefore, a need exists to develop active packaging which can gradually deliver antioxidants in a controlled manner. The objectives of this research were to (1) form and characterize cyclodextrin inclusion complexes with the natural antioxidants, alpha-tocopherol and quercetin, (2) incorporate cyclodextrin inclusion complexes of natural antioxidants into linear low density polyethylene (LLDPE), and (3) measure the release kinetics of inclusion complexes of natural antioxidants from LLDPE into a model food system. Cyclodextrin inclusion complexes of alpha-tocopherol and quercetin were formed by the coprecipitation method and characterized in the solid state by NMR, IR spectroscopy, and thermal analyses. Solid inclusion complex products of alpha-tocopherol:beta-cyclodextrin and quercetin:gamma-cyclodextrin had molar ratios of 1.7:1 as determined by UV spectrophotometry, which were equivalent to 18.1% (w/w) alpha-tocopherol and 13.0% (w/w) quercetin. Free and cyclodextrin complexed antioxidant additives were compounded with a twin-screw mixer into two LLDPE resin types followed by compression molding into films. Release of alpha-tocopherol and quercetin from LLDPE films into coconut oil at 30 Â°C was quantified by HPLC during 4 weeks of storage. The total release of alpha-tocopherol after 4 weeks was 70% from the free form and 8% from the complexed form averaged across both LLDPE resins. The mechanism by which alpha-tocopherol was released was modified due to its encapsulation inside the beta-cyclodextrin cavity within the LLDPE matrix as indicated by its diffusion coefficient decreasing by two orders of magnitude. Molecular encapsulation of natural antioxidants using cyclodextrins may be used as a controlled release mechanism within polymer food packaging to gradually deliver an effective antioxidant concentration to a food product, thereby, limiting oxidation, maintaining nutritional quality, and extending shelf life.
Ph. D.

APA, Harvard, Vancouver, ISO, and other styles

8

Trombley, John D. "Polyphenols: Interactions with proteins and analytical methods." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1322841396.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Comunian, Talita Aline. "Microencapsulação de ácido ascórbico por coacervação complexa e dispositivos microfluídicos: estudo estrutural, estabilidade e aplicação das microcápsulas." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/74/74132/tde-03122013-162024/.

Full text

Abstract:

Reações de oxidação lipídica são responsáveis pelo desenvolvimento de sabores e odores desagradáveis tornando os alimentos impróprios para consumo, sendo necessário o uso de antioxidantes. O ácido ascórbico (AA) é um antioxidante muito eficaz, que exibe função vitamínica, no entanto é relativamente instável. Com o objetivo de aumentar a estabilidade do AA e, consequentemente, facilitar sua aplicação em produtos alimentícios, os métodos de encapsulação por coacervação complexa e por dispositivos microfluídicos foram testados. Primeiramente foi apresentada a Revisão Bibliográfica no Capítulo 1, e em seguida, a encapsulação por coacervação complexa, como será visto no Capítulo 2. Neste caso, nove tratamentos foram obtidos utilizando-se gelatina e goma arábica como materiais de parede e analisados com relação à morfologia, por microscopia ótica e eletrônica de varredura, umidade, atividade de água, higroscopicidade, solubilidade, potencial zeta, espectroscopia no infravermelho por transformada de Fourier (Ftir), tamanho e distribuição de tamanho de partículas, cor instrumental, eficiência de encapsulação e estabilidade do material encapsulado. No capítulo 3 serão apresentados resultados obtidos na encapsulação do AA pelo método de dispositivos microfluídicos. Cinco tratamentos foram obtidos, sendo analisados com relação à morfologia, por microscopia ótica, eletrônica de varredura e confocal, eficiência de encapsulação, tamanho e distribuição de tamanho de partícula e estabilidade do material encapsulado. A obtenção das microcápsulas de AA pelos dois métodos citados foi viável uma vez que apresentaram altos valores de eficiência de encapsulação e ótima atuação em relação à proteção do AA durante estocagem. Comparando-se os dois métodos, as cápsulas obtidas por dispositivos microfluídicos conferiram melhor estabilidade ao ácido ascórbico, no entanto amostras obtidas por coacervação complexa foram aplicadas em salsicha devido a maior quantidade de AA presente em sua constituição. O efeito da aplicação das microcápsulas nas salsichas foi avaliado durante 40 dias de armazenamento refrigerado como será visto no Capítulo 4. Cinco tratamentos foram elaborados e analisados de acordo com a estabilidade da emulsão cárnea durante o processamento, umidade, atividade de água, alteração do pH, determinação da cor instrumental, perfil de textura instrumental, estabilidade oxidativa pelo método de substâncias reativas ao ácido tiobarbitúrico (TBARS) e aceitação sensorial. A aplicação das microcápsulas de AA em salsicha foi possível sem comprometer a qualidade do produto final. Todos os dados obtidos foram analisados estatisticamente por análise de variância ANOVA e teste de Tukey, ao nível de 5% de significância com auxílio do programa SAS. Os experimentos relacionados à encapsulação por coacervação complexa e aplicação das microcápsulas em salsicha foram realizados no Laboratório de Produtos Funcionais, nas dependências do Departamento de Engenharia de Alimentos da FZEA/USP. Os experimentos relacionados à utilização de dispositivos microfluídicos foram realizados nos laboratórios do professor David A. Weitz, da Escola de Engenharia e Ciências Aplicadas de Harvard, da Universidade de Harvard, Cambridge, Estados Unidos.
Lipid oxidation reactions are responsible for the development of unpleasant tastes and odors making food unfit for consumption. For this reason, the use of antioxidant is necessary. Ascorbic acid (AA) is a very effective antioxidant with vitamin function, however it is relatively unstable. With the aim of increasing the stability of AA and thus improve its application in food products, the methods of encapsulation by complex coacervation and microfluidic devices were tested. First of all the Literature Review is presented in Chapter 1. The encapsulation by complex coacervation can be seen in Chapter 2. For this methodology, nine treatments were obtained using gelatin and gum Arabic as encapsulant agent and analyzed regarding to morphology by optical and scanning electron microscopy, moisture, water activity, hygroscopicity, solubility, Zeta Potential, Fourier transform infrared Spectroscopy (FTIR), particle size and particle size distribution, instrumental color, encapsulation efficiency and stability of the encapsulated material. The results obtained for AA encapsulation by microfluidic device will be presented in Chapter 3. Five treatments were obtained and analyzed regarding to morphology by optical, scanning electron and confocal microscopy, encapsulation efficiency, particle size and particle size distribution and stability of the encapsulated material. The production of AA microcapsules by the two methods mentioned was feasible once that showed high levels of encapsulation efficiency and optimal performance regarding to the protection of AA during storage. Comparing the two methods, the microcapsules obtained by microfluidic device conferred better stability to AA, however samples obtained by complex coacervation were applied in sausage due to the greater amount of AA in its constitution. The effect of the application of microcapsules in sausages was evaluated during 40 days at refrigerated storage as it will be seen in Chapter 4. Five treatments were prepared and analyzed according to the stability of the meat emulsion during processing, moisture, water activity, pH changes, determination of instrumental color, instrumental texture profile, oxidative stability by the method of thiobarbituric acid reactive substances (TBARS) and sensory acceptance. The application of AA microcapsules in sausage was possible without compromising the quality of the final product. All data were statistically analyzed by ANOVA and Tukey test, at 5% of significance with the use of SAS software. The experiments related to encapsulation by complex coacervation and application of microcapsules in sausage were carried out at Laboratory of Functional Products, at Department of Food Engineering, FZEA / USP. The experiments related to the use of microfluidic devices were performed in the laboratories of Professor David A. Weitz, at School of Engineering and Applied Sciences of Harvard, at Harvard University, Cambridge, USA.

APA, Harvard, Vancouver, ISO, and other styles

10

Ferreira, Rafael de Queiroz. "Desenvolvimento e aplicação de um novo ensaio para a determinação eletroquímica da capacidade antioxidante de compostos modelo e de matrizes complexas." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-26082009-111616/.

Full text

Abstract:

Este trabalho descreve o desenvolvimento e aplicações práticas de uma nova e simples metodologia eletroquímica para a determinação da capacidade antioxidante de moléculas modelo específicas e/ou algumas amostras complexas de alimentos normalmente consumidas no Brasil. Outros sistemas de interesse teórico ou tecnológico também foram investigados. O método se baseia no uso de uma quantidade conhecida de um íon inorgânico como oxidante e na determinação cronoamperométrica de sua concentração remanescente após reação com as espécies antioxidantes de interesse. Contudo, testes iniciais para diferentes marcas comerciais de sucos de laranjas usando Fe3+ como oxidante (ensaio FRAP modificado), só obtiveram êxito quando o antioxidante apresenta um comportamento eletroquímico totalmente irreversível como, por exemplo, o ácido ascórbico. Para superar esse problema, o ensaio foi então desenvolvido usando o Ce4+ como oxidante (ensaio CRAC) uma vez que sua redução após reação pode ser realizada em 0,8 V vs Ag/AgCl, uma região de potencial na qual não ocorre a redução das espécies formadas pela oxidação reversível ou quase reversível do antioxidante. Devido ao elevado potencial anódico requerido quando o Ce4+ é usado, foi necessário um filme de diamante dopado com boro como eletrodo de trabalho. Após uma rigorosa caracterização do sistema eletroquímico, foram realizadas determinações da capacidade antioxidante de oito compostos padrões (ácido ascórbico, ácido gálico, ácido tânico, BHA, catequina, quercetina, rutina e trolox), usando o ensaio CRAC. Os resultados mostraram uma correlação satisfatória com ensaios mais complexos reportados na literatura e foram aplicados em um conjunto de sucos de frutas industrializados, mostrando valores máximos com quase uma ordem de grandeza superior ao apresentado pelo composto de referência (trolox), com a seguinte seqüência de capacidade antioxidante: caju > goiaba > uva > manga > laranja > maracujá. Considerando a busca da indústria local de \"cachaça\" por madeiras alternativas em contrapartida aos tonéis de carvalho, o ensaio CRAC foi realizado usando quatro extratos etanólicos de madeiras brasileiras [Pequi (Caryocar brasiliense), Imbuia (Octea porosa), Cabreúva (Myrocarpus frondosus) e Cabreúva-vermelha (Myroxylon balsamum)] assim como um extrato de Carvalho (Quercus sp), para comparação. Os resultados indicaram um aumento na capacidade antioxidante na ordem apresentada acima e, apesar da melhor amostra (Cabreúva-vermelha) ter apenas 60% da capacidade antioxidante apresentada pelo carvalho, sua disponibilidade e preço despertam o interesse por pesquisas futuras. Uma avaliação comparativa dos resultados obtidos usando os ensaios CRAC e DPPH foi realizado para extratos metanólicos de cana-de-açúcar e polpa de maracujá. Essa comparação revelou uma diferença quantitativa entre os valores dos ensaios, porém, a hierarquia foi mantida para cada conjunto de resultado. Esse efeito foi atribuído às diferenças nos mecanismos dominantes para a desativação radicalar, bem como para as condições experimentais de cada ensaio. A correlação entre a estrutura e a atividade antioxidante de moléculas modelo de flavonóides sob investigação foi relatada devido à presença de certos grupos substituintes na estrutura de difenilpirano. A atividade hierárquica para tais grupos foi estabelecida como: OH(C2´C4´) > OH(C4´) ~ OH(C3´C4´) > C2=C3 + 4-oxo > OH(C3,C5) + 4-oxo > OH(C3) + 4-oxo > OH(C5) + 4-oxo > OH(C3,C5). A formação de complexos entre flavonóides e íons metálicos, tal como o Fe2+, tem um forte efeito sobre a capacidade antioxidante e o ensaio CRAC mostrou que para a morina, quercetina e fisetina, esse aumento foi de 15,3; 31,8 e 27,9%, respectivamente. Por outro lado, para a catequina e crisina, o aumento foi de apenas 1,8 e 7,8%, respectivamente. Esses aumentos foram relatados devido à presença de, pelo menos, um dos três tipos de sítios ativos na molécula polifenólica que interage com íons metálicos. Todos esses resultados confirmam que o ensaio CRAC é uma ferramenta simples e viável para a determinação da capacidade antioxidante de uma variedade de sistemas práticos e moléculas modelo.
This work describes the development and practical applications of a novel and simple electrochemical methodology for the determination of the antioxidant capacity of specific model molecules and/or some complex food samples currently consumed in Brazil. Other systems having either theoretical or technological interest were also investigated. The method is based on the use of a known amount of an inorganic ion as the oxidant and in the chronoamperometric determination of its remaining concentration after reaction with the chosen antioxidant species. However, initial tests for different commercial brands of orange juices using Fe3+ as the oxidant (modified FRAP assay) were only successful when the antioxidant has a totally irreversible electrochemical behavior as, for example, ascorbic acid. To overcome this problem, the assays were then performed using Ce4+ as the oxidant (the CRAC assay) since its reduction after reaction can be carried out at 0.8 V vs Ag/AgCl, a potential region where the reduction of species formed by the reversible or quasi-reversible oxidation of the antioxidant does not occur. Due to the high anodic potentials required when using Ce4+, it was necessary to have a boron-doped diamond film as the working electrode. After a rigorous characterization of the electrochemical systems, measurements of the antioxidant capacity of eight standard compounds (ascorbic acid, gallic acid, tannic acid, BHA, catechin, quercetin, rutin and trolox) were carried out using the CRAC assay. The results showed a satisfactory correlation with those reported in the literature using other more complex assays and these studies were then applied to a set of industrialized fruit juices showing maximum values almost one order of magnitude higher than that of the reference compound (trolox) and following the antioxidant capacity sequence: cashew>guava>grape>mango>orange>passion fruit. Considering that the local \"cachaça\" industry is looking for alternative woods to the use of oak barrels, CRAC assays were carried out using four ethanol extracts of Brazilian woods [Pequi (Caryocar brasiliense), Imbuia (Octea porosa), Cabreúva (Myrocarpus frondosus) e Cabreúva-vermelha (Myroxylon balsamum)] as well as an Oak (Quercus sp) extract, for comparison. The results indicate an increasing antioxidant capacity in the order presented above and, although the best sample (Cabreúva-vermelha) has only 60% of the capacity shown by oak, its local availability and price makes it interesting for further research. A comparative evaluation of the results obtained using the CRAC and the DPPH assays was carried out for methanol extracts of sugar cane juice and passion fruit pulp. That comparison revealed a quantitative difference between the assay values but the hierarchy was maintained for each set of results. Such effect was attributed to differences in the prevailing mechanism for radical deactivation, as well as, the experimental conditions used for each assay. The correlation between structure and antioxidant activity of model flavonoid molecules under investigation was related to the presence of certain groups in the diphenilpyrene structure. The activity hierarchy for them was established as: OH(C2´C4´) > OH(C4´) ~ OH(C3´C4´) > C2=C3 + 4-oxo > OH(C3,C5) + 4-oxo > OH(C3) + 4-oxo > OH(C5) + 4-oxo > OH(C3,C5). The complex formation between flavonoids and metal ions, such as Fe2+, has a strong effect on the antioxidant capacity and CRAC assay showed that for morin, quercetin and fisetin the increase was 15.3, 31.8 and 27.9%, respectively. On the other hand, for catechin and chrysin the increase was only 1.8 and 7.8%, respectively. These increases were related to the presence of, at least, one of three types of active sites in the polyphenolic molecule that can interact with metal ions. All these findings confirm that the CRAC assay is simple and convenient tool for the determination of the antioxidant capacity of a variety of practical systems and model molecules.

APA, Harvard, Vancouver, ISO, and other styles

11

Lamônica, Vânia Cristina [UNESP]. "Efeitos da intervenção nutricional pós-operatória com vitaminas do complexo B sobre os indicadores metabólicos da via sulfurada e a sobrevida de pacientes com câncer de esôfago." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/105886.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:35:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-27Bitstream added on 2014-06-13T20:06:27Z : No. of bitstreams: 1 lamonica_vc_dr_botfm.pdf: 534692 bytes, checksum: 96b46084f1cbd2b18da6d1b7c6c31d1e (MD5)
Em cada célula existe uma batalha entre a produção de componentes oxidantes provenientes do metabolismo aeróbico e antioxidantes enzimáticos e não enzimáticos naturais. Entre eles, há os compostos sulfurados. O estresse oxidativo desenvolve um papel chave na produção de processos patológicos crônicos como câncer oral. Em uma revisão não sistemática da literatura disponível nós verificamos que o câncer de esôfago é conhecido por sua marcada variação por regiões geográficas e etnia racial e diferenças dietéticas o que poderia contribuir com algumas destas disparidades. Deficiências nutricionais de frutas frescas, vegetais e fibras dietéticas são comumente referidas associadas com a presença de câncer de esôfago. Alem disso, consumo pesado de bebidas alcoólicas de tabaco, e outros riscos de câncer podem interferir no consumo de vitaminas lipossolúveis e hidrossolúveis e componentes dietéticos com potencial efeito anticancerígeno. Para nosso entendimento a adequação de vitaminas do complexo B poderia permitir o total efeito das defesas antioxidantes dos compostos sulfurados
In every cell, there is an ongoing battle between the production of oxidants components from the aerobic metabolism and the antioxidants of enzymatic and nonenzymatic nature. Among the later are the sulfur-containing compounds. The oxidative stress plays a key role in production of chronic pathological processes such as oral cancer. In a non-systematic review of the available literature we found that esophageal cancer is known for its marked variation by geographic regions and race ethnicity and the dietary differences may account for at least some of these disparities. Nutritional deficits in fresh fruits, vegetables and dietary fiber are commonly referred as associated with the presence of esophagus cancer. Moreover heavy consumption of alcoholic beverages and tobacco, the other risk factors for the cancer, can interfere with the consumption of liposoluble and hydrosoluble vitamins and dietary components with potential anti-carcinogenic effects. To our understanding the adequacy of B-vitamins would allow the full effects of the sulfurcontaining antioxidative defenses

APA, Harvard, Vancouver, ISO, and other styles

12

Lamônica, Vânia Cristina. "Efeitos da intervenção nutricional pós-operatória com vitaminas do complexo B sobre os indicadores metabólicos da via sulfurada e a sobrevida de pacientes com câncer de esôfago /." Botucatu, 2013. http://hdl.handle.net/11449/105886.

Full text

Abstract:

Orientador: Maria Aparecida Arruda Coelho Henry
Coorientador: Roberto Carlos Burini
Banca: Luis Roberto Lopes
Banca: Yara Baxter Carnavalli
Banca: Luciene S. Venâncio Lotufo Brant
Banca: Camila Renata Correa
Resumo: Em cada célula existe uma batalha entre a produção de componentes oxidantes provenientes do metabolismo aeróbico e antioxidantes enzimáticos e não enzimáticos naturais. Entre eles, há os compostos sulfurados. O estresse oxidativo desenvolve um papel chave na produção de processos patológicos crônicos como câncer oral. Em uma revisão não sistemática da literatura disponível nós verificamos que o câncer de esôfago é conhecido por sua marcada variação por regiões geográficas e etnia racial e diferenças dietéticas o que poderia contribuir com algumas destas disparidades. Deficiências nutricionais de frutas frescas, vegetais e fibras dietéticas são comumente referidas associadas com a presença de câncer de esôfago. Alem disso, consumo pesado de bebidas alcoólicas de tabaco, e outros riscos de câncer podem interferir no consumo de vitaminas lipossolúveis e hidrossolúveis e componentes dietéticos com potencial efeito anticancerígeno. Para nosso entendimento a adequação de vitaminas do complexo B poderia permitir o total efeito das defesas antioxidantes dos compostos sulfurados
Abstract: In every cell, there is an ongoing battle between the production of oxidants components from the aerobic metabolism and the antioxidants of enzymatic and nonenzymatic nature. Among the later are the sulfur-containing compounds. The oxidative stress plays a key role in production of chronic pathological processes such as oral cancer. In a non-systematic review of the available literature we found that esophageal cancer is known for its marked variation by geographic regions and race ethnicity and the dietary differences may account for at least some of these disparities. Nutritional deficits in fresh fruits, vegetables and dietary fiber are commonly referred as associated with the presence of esophagus cancer. Moreover heavy consumption of alcoholic beverages and tobacco, the other risk factors for the cancer, can interfere with the consumption of liposoluble and hydrosoluble vitamins and dietary components with potential anti-carcinogenic effects. To our understanding the adequacy of B-vitamins would allow the full effects of the sulfurcontaining antioxidative defenses
Doutor

APA, Harvard, Vancouver, ISO, and other styles

13

James, Leanne. "Manganese complexes with biomimetic antioxidant activity." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/7073.

Full text

Abstract:

Several seven-coordinate manganese complexes have been synthesised, characterised and tested for both superoxide dismutase and catalase activity. Macrocyclic ring contractions have led to a series of new seven coordinate mononuclear manganese(II) macrocycles that have potential for their use as working superoxide dismutase mimics. Numerous polynuclear seven coordinate manganese(II) macrocycles have been synthesised via Schiff base condensation. Subsequent reduction of the imine bonds has led to a variety of reduced amine analogues with varying axial ligands. The geometry has been compared about the manganese centres where possible. From the results of each complex tested for superoxide dismutase activity, the µ-chloro bridged tetranuclear complex [Mn2(C24H29N6O2)(Cl)2]2(ClO4)2 has proved to be the most efficient mimic with a calculated KMcCF value of 7.7 x 106 [M-1 s-1]. A method for measuring catalase activity has been developed, and the most efficient catalase active compound was found to be [Mn5(C24H29N6O2)2(OAc)2(ClO4)2](ClO4)2 with one molecule of complex breaking down approximately 59000 molecules of hydrogen peroxide after one minute. Catalase testing showed that a reduction of the imine bonds produced an increase in activity overall for the complexes of H2L1 (C24H29N6O2), but a decrease was observed for the reduced tripodal complexes. An increase in the number of manganese centres resulted in a rise in catalase activity. Many of the complexes tested for catalase activity showed an induction period prior to the activity being observed. This may suggest that the complexes undergo a change in structure, or that there is a rearrangement occurring before catalase activity may be observed. The results that are presented indicate that the axial ligands have an effect on the rate of catalase activity and the observed induction period. Of the molecules that were tested for both superoxide dismutase and catalase activity, the pentanuclear complex [Mn5(C24H29N6O2)2(OAc)2(ClO4)2](ClO4)2 showed high activity for both analyses. This may be due to the extra manganese centre within the complex and the axial ligands that are present when compared with other tetranuclear complexes. The complex [Mn5(HL1)(OAc)2(ClO4)2](ClO4)2 may prove to be a good candidate for a working superoxide dismutase mimic. Ring contracted complexes show high rates of superoxide dismutase activity but possess limited catalase activity. Attempts have been made to produce a direct method of measuring superoxide dismutase activity using a stop-flow technique to complement the results using the indirect NBT (Nitro blue Tetrazoleum) method. This was carried out by analysing low concentration solutions of both complex and superoxide on a millisecond timescale. Progress has been made for this method with preliminary results being obtained.

APA, Harvard, Vancouver, ISO, and other styles

14

Paudel, Liladhar. "High Field ¹H Nuclear Magnetic Resonance (NMR) Spectroscopy Based Metabolomics and Complex Mixture Analysis by Multidimensional NMR and Liquid Chromatography-Mass Spectrometry (LC-MS)." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1343403647.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Junior, Flavio Bueno de Camargo. "Estabilidade e eficácia de formulações cosméticas contendo extrato de Myrtus communis e um complexo vitamínico hidratante." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/60/60137/tde-14042011-195331/.

Full text

Abstract:

Considerando que a tendência atual em termos de formulações cosméticas é a veiculação de diferentes substâncias ativas num mesmo produto, visando o sinergismo de efeito, o objetivo desse trabalho foi a avaliação da estabilidade, da segurança e da eficácia clínica de formulações cosméticas, contendo extrato de Myrtus communis e um complexo vitamínico hidratante à base de D-pantenol e derivados de vitaminas C e E, bem como a avaliação da atividade antioxidante in vitro do extrato objeto de estudo. Para tal, na primeira etapa do estudo foram elaboradas 4 formulações de géis creme, F1 (veículo), F2 (veículo acrescido de extrato hidrolisado de Myrtus communis), F3 (veículo acrescido de D-pantenol) e F4 (veículo acrescido de extrato hidrolisado de Myrtus communis e D-pantenol), as quais foram submetidas a testes preliminares de estabilidade e à avaliação do comportamento reológico, da compatibilidade cutânea e da eficácia clínica, por métodos subjetivos (avaliação sensorial) e quantitativos por técnicas de biofísica e análise de imagem da pele. No estudo clínico as formulações foram aplicadas nos antebraços e na face das voluntárias, sendo realizadas medidas do conteúdo aquoso do estrato córneo, da perda de água transepidérmica (TEWL), do micro-relevo cutâneo e da anisotropia da pele, antes (basal) e após 3 horas (efeito imediato) 15 e 30 dias de aplicação das formulações (efeito em longo prazo). Os dados foram analisados estatisticamente pelo teste paramétrico análise de variância. A seguir, a formulação que apresentou melhores resultados na avaliação sensorial e estudo de eficácia, foi acrescida de Tetraisopalmitato de ascorbila (F5) ou Vitamina E - D-Alfa Tocoferol Acetato (F6) ou associação destes (F7). As referidas formulações foram submetidas aos testes de estabilidade e eficácia clínica. De acordo com os resultados obtidos, as formulações foram consideradas estáveis e seguras, sendo que a formulação de nº 4 foi a que apresentou o melhor sensorial, de acordo com as voluntárias sendo, portanto, selecionada para ser acrescida dos derivados de vitaminas objeto de estudo. Na avaliação dos efeitos imediatos, as formulações estudadas aumentaram significativamente o conteúdo aquoso do estrato córneo nas regiões dos antebraços e da face, quando comparadas com os valores basais. Em relação à TEWL, foi possível observar que as formulações nos 2, 3 e 4 provocaram melhora na função barreira da pele dos antebraços, enquanto que na face apenas as formulações nos 3 e 4 provocaram melhora neste parâmetro. Na avaliação em longo prazo, todas as formulações estudadas, proporcionaram um aumento significativo no conteúdo aquoso do estrato córneo após 15 e 30 dias de aplicação, enquanto que somente as formulações que continham as substâncias ativas objeto de estudo, ou seja, as nos 2, 3 e 4, melhoraram a função barreira da pele. No estudo de eficácia clínica onde as formulações F4 (veículo acrescido de extrato hidrolisado de Myrtus communis e D-pantenol) e F7 (veículo acrescido de extrato hidrolisado de Myrtus communis, D-pantenol e os derivados de vitamina C e E) foram avaliadas comparativamente, foi possível observar um aumento significativo nos valores do conteúdo aquoso do estrato córneo, em relação aos valores basais e a região controle (região que não recebeu aplicação de nenhuma formulação), após 15 dias de aplicação. Em relação à TEWL, apenas a formulação F4 (veículo acrescido de extrato hidrolisado de Myrtus communis e D-pantenol) provocou melhora na função barreira. De acordo com os resultados obtidos, as formulações desenvolvidas neste estudo apresentaram efeito hidratante pronunciado e, as que continham o extrato Myrtus communis e D-pantenol, protegeram a função barreira da pele. Além disso, o extrato de Myrtus communis demonstrou atividade antioxidante pronunciada, efeito considerado muito importante para o emprego deste extrato em cosméticos com finalidades antienvelhecimentos. Finalizando, este estudo mostrou a importância do desenvolvimento de formulações cosméticas estáveis, de sensorial adequado e com eficácia comprovada, contendo o extrato hidrolisado de Myrtus communis e o complexo vitamínico objeto de estudo, para a hidratação, proteção e melhora das condições gerais da pele.
Considering that the current trend in terms of cosmetic formulations is to vehicle different active ingredients in one single product, aiming the effect of synergism, the objective of this study was to evaluate the stability, safety and clinical efficacy of cosmetic formulations containing extract of Myrtus communis and a moisturizing vitamin complex based on D-panthenol and derivatives of vitamins C and E, as well as to evaluate the extract in vitro antioxidant activity. Thus, for the first study stage, four gel cream formulations were developed, F1 (vehicle), F2 (vehicle supplemented with Myrtus communis hydrolyzate extract), F3 (vehicle supplemented with D-panthenol) and F4 (vehicle supplemented with Myrtus communis hydrolyzate extract and D-panthenol), which were submitted to preliminary stability tests, to rheological behavior assessment, to skin compatibility test and to clinical efficacy assessment, by subjective methods (sensorial evaluation) and quantitative methods, by biophysics techniques and skin image analysis. In the clinical study, the formulations were applied on the volunteers´ face and forearms, with measurements of the stratum corneum water content, transepidermal water loss (TEWL), skin micro-relief and skin anisotropy before (baseline) and after 3 hours (immediate effects), 15 and 30 days of the formulations application (long-term effects). Data were statistically analyzed by parametric test analysis of variance. Afterwards, the formulation that showed best performance in sensory evaluation and clinical efficacy study was supplemented with ascorbyl tetraisopalmitate (F5) or Vitamin E - D-Alpha-Tocopherol Acetate (F6) or a combination of both derivatives of vitamins, C and E (F7). According to the obtained results, all the formulations were considered safe and stable, and formulation 4 was the one with the best sensorial performance, according to the volunteers perception, and, therefore, it was selected to be supplemented with the vitamin derivatives under study. The immediate effects evaluation demonstrated that all the other formulations significantly increased stratum corneum water content in the face and forearms skin, when compared to baseline values. In relation to TEWL, it was observed that the formulations 2, 3 and 4 provoked an improvement in forearm skin barrier function, while only formulations 3 and 4 provoked an improvement on this parameter on the face. In the long-term assessment, all formulations studied promoted a significant increase in stratum corneum water content after 15 and 30 days of the formulations application, while only formulations containing the studied active ingredients, i.e., formulations 2, 3, and 4 improved skin barrier function. In the clinical efficacy study when the formulations F4 (vehicle supplemented with Myrtus communis hydrolyzate extract and D-panthenol) and F7 (vehicle supplemented with Myrtus communis hydrolyzate extract, D-panthenol and derivatives of vitamin C and E) were comparatively assessed, it was possible to observe a significantly increase in stratum corneum water content, when compared to baseline values and to control areas (region which received no formulation), after 15 days of formulations application. Regarding TEWL, only formulation F4 (vehicle supplemented with Myrtus communis hydrolyzate extract and D-panthenol) provoked an improvement in skin barrier function. According to the obtained results, the formulations developed in this study demonstrated a pronounced moisturizing effect, and those containing Myrtus communis extract and D-panthenol, protected the skin barrier function. Moreover, the extract of Myrtus communis demonstrated a pronounced antioxidant activity, an effect considered very important for this extract use in cosmetics aiming anti-aging purposes. Finally, this study demonstrated the relevance of developing stable cosmetic formulations, with adequate sensory characteristics and proven effectiveness, supplemented with Myrtus communis hydrolyzed extract and with the vitamin complex under study, for skin hydration, protection and improvement of general skin conditions

APA, Harvard, Vancouver, ISO, and other styles

16

Andrade, Micássio Fernandes de. "Estudo da atividade antioxidante de derivados 3-fenilcumarínicos no metabolismo oxidativo de neutrófilos humanos estimulados por complexos imunes." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/17/17147/tde-16052012-203921/.

Full text

Abstract:

A produção de espécies reativas de oxigênio (ERO) pelos neutrófilos, que representa um mecanismo essencial da imunidade inata contra agentes infecciosos, pode ser desencadeada por imunocomplexos (IC) associados ou não com componentes do sistema complemento. Os IC são normalmente eliminados da circulação pela ligação aos receptores de complemento do tipo 1 em eritrócitos, que os transportam até o baço e o fígado, onde são fagocitados por macrófagos residentes. Porém, defeitos neste mecanismo de eliminação podem levar à deposição de IC nos vasos e tecidos. Em algumas doenças inflamatórias, onde ocorre uma intensa deposição de IC, pode acontecer o recrutamento e a ativação maciça de neutrófilos pelos IC. Nessa situação, os mecanismos endógenos de defesa tecidual não conseguem controlar as alterações desencadeadas pelos fatores oxidantes e líticos liberados pelos neutrófilos, levando à possível lesão tecidual e consequências funcionais e estruturais para o organismo. Nessa perspectiva, tem-se intensificado, nos últimos anos, a procura por novos compostos terapêuticos com capacidade de reduzir os danos aos tecidos adjacentes ao acúmulo de IC, neutrófilos, ERO e enzimas líticas, expostos a níveis deletérios desses componentes. Assim, neste trabalho foi avaliado o potencial antioxidante de um conjunto de dez derivados 3-fenilcumarínicos no metabolismo oxidativo de neutrófilos humanos estimulados por ICs, empregando-se o ensaio de quimioluminescência dependente de luminol e de lucigenina (QLlum e QLluc, respectivamente). Posteriormente, foi avaliada a citoxicidade das amostras, através do ensaio de exclusão do azul de tripan e medida da atividade da lactato desidrogenase liberada, bem como sua capacidade de sequestrar HOCl e inibir a atividade das enzimas NADPH oxidase e mieloperoxidase (MPO). Observou-se que todas as amostras avaliadas inibiram a QLlum e a QLluc, sendo que cinco delas tiveram efeito inibitório maior que ou igual a 50% (C6, C13, C13a, C24 e C24a)*. Este efeito biológico não foi mediado pela citotoxicidade das 3-fenilcumarinas, nas condições avaliadas. Dentre essas amostras, o derivado 3-fenilcumarínico C13, que foi o mais efetivo em inibir a QLluc, possui duas características que parecem estar relacionadas com tal efeito: um grupo substituinte orto-diidroxi no esqueleto cumarínico e um grupo metilenodioxila no anel fenílico. Além do mais, todas as substâncias que possuem o grupo metilenodioxila no anel fenílico (C1, C6, C6a, C13, C13a) apresentaram efeito inibitório da QLluc maior que as respectivas análogas sem este substituinte (C15, C18, C18a, C24, C24a). A inibição da QLluc parece ser independente da inibição da atividade da NADPH oxidase, visto que as substâncias apresentaram efeito inibitório discreto no consumo de O2 pelos neutrófilos estimulados por IC. Por outro lado, as amostras C13 e C24, que têm em comum a presença do grupo substituinte 6,7-diidroxi, apresentaram os maiores efeitos inibitórios sobre a QLlum, apresentando IC50 semelhante. Essas duas substâncias também foram as mais ativas em inibir a atividade da enzima MPO e em sequestrar o HOCl. Para esses dois ensaios, a atividade biológica observada foi dependente do número de hidroxilas na estrutura do derivado 3-fenilcumarínico. Os resultados deste trabalho mostram que a atividade antioxidante dos derivados 3-fenilcumarínicos sobre o metabolismo oxidativo de neutrófilos humanos está relacionada às características estruturais dessas moléculas. Dentre a série de substâncias avaliadas, C13 e C24 são as amostras mais promissoras para uso como protótipos de moléculas com aplicação terapêutica na modulação desta função neutrofílica.
Production of reactive oxygen species (ROS) by neutrophils, which is an essential mechanism of innate immunity against infectious agents, can be triggered by immune complexes (IC) associated or not with components of the complement system. IC are normally cleared from the circulation by binding to complement receptor type 1 on erythrocytes and transport to spleen and liver, where they are phagocytized by resident macrophages. However, defects in this clearance mechanism can lead to deposition of IC in vessels and tissues, favoring neutrophil chemotaxis. In some inflammatory diseases there is intense deposition of IC, which triggers massive recruitment and activation of neutrophils. In these situations, the endogenous tissue defense mechanisms are not able to regulate the local disorders provoked by the oxidant and lytic compounds released by neutrophils, and tissue damage as well as structural and functional consequences to the organism might occur. In this perspective, the last years have been marked by an intense search for new therapeutic compounds able to reduce the damage to tissues surrounding the site of accumulation of IC, neutrophils, ROS and lytic enzymes, exposed to deleterious levels of these components. So, the present work reports the evaluation of the antioxidant potential of ten 3-phenylcoumarin derivatives in the neutrophil oxidative metabolism stimulated with IC, through the luminol- and lucigenin-dependent chemiluminescence assay (QLlum and QLluc, respectively). Further, cytotoxicity of the samples was evaluated by the trypan blue exclusion assay and measurement of lactate dehydrogenase activity, as well as their ability to scavenge HOCl and inhibit NADPH-oxidase and myeloperoxidase (MPO) activity. We found that all the samples inhibited QL-lum and QLluc, being the inhibitory effect of five of them higher than or equal to 50% (C6, C13, C13a, C24 e C24a)*. This biological effect was not mediated by cytotoxicity of the 3-phenylcoumarins, under the conditions assessed. Compound C13, which was the most effective inhibitor of QLluc among the set of phenylcoumarins tested, has two structural features that seem to be related to this effect: an orto-dihydroxyl group in the coumarin moiety and a methylenedioxyl group attached to the phenyl ring. Moreover, the inhibitory effect of all 3-phenylcoumarins bearing the methylenedioxyl group (C1, C6, C6a, C13, C13a) was higher than that found to their analogues without this group (C15, C18, C18a, C24, C24a). The CLluc inhibition by phenylcoumarins seems to be independent of inhibition of NADPH-oxidase activity, since these compounds had a slight inhibitory effect in the O2 consumption by IC-stimulated neutrophils. On the other hand, compounds C13 and C24, which shares the 6,7-dihydroxyl group, had the highest inhibitory effects on CLlum with similar IC50 values among the samples tested. These compounds were also the most active ones to inhibit MPO activity and scavenge HOCl. Such biological effects were dependent on the number of hydroxyl groups in the 3-phenylcoumarin moiety. The results of this work show that the antioxidant activity of 3-phenylcoumarin derivatives in the oxidative metabolism of human neutrophils is related to the structural characteristics of these molecules. Among the set of compounds evaluated, C13 and C24 are the most promising samples to be used as prototypes of moleculse with therapeutic application in the modulation of neutrophil function.

APA, Harvard, Vancouver, ISO, and other styles

17

Kabeya, Luciana Mariko. "Estudo do efeito modulatório de derivados de 3-fenilcumarina nas funções de neutrófilos estimulados por imunocomplexos e análise da relação estrutura-atividade." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/60/60138/tde-01122010-161248/.

Full text

Abstract:

A formação de complexos antígeno-anticorpo ou imunocomplexos (ICs) na circulação e sua eliminação faz parte dos mecanismos de defesa imune humoral do ser humano. Em algumas patologias, como lupus eritematoso sistêmico, artrite reumatóide e vasculite auto-imune, ocorre um desequilíbrio nesse processo, que leva à deposição dos ICs nos tecidos e ao desencadeamento de uma reação inflamatória. Esta, por sua vez, envolve o recrutamento e ativação de neutrófilos, que têm importante participação na patogênese dessas doenças. A ativação dos neutrófilos pelos ICs, via receptores para a porção Fc de IgG (FcR) e receptores de complemento (CR), desencadeia diversas funções efetoras, tais como fagocitose, desgranulação e o metabolismo oxidativo, com a produção de espécies reativas de oxigênio (EROs). Estas funções estão envolvidas na digestão dos ICs, na morte de microorganismos, e na regulação do processo inflamatório. Entretanto, nas doenças mediadas por ICs, os neutrófilos ativados liberam grandes quantidades de enzimas e EROs para o meio extracelular, contribuindo para a lesão dos tecidos do hospedeiro e a amplificação do processo inflamatório. Neste trabalho foi avaliado o efeito modulatório de vinte derivados de 3-fenilcumarina nas funções de neutrófilos estimulados por ICs de ovalbumina (OVA) e IgG anti-OVA. Além disso, foi feita a investigação mecanismos de ação dessas substâncias e a análise da relação estrutura-atividade. O metabolismo oxidativo dos neutrófilos ativados por ICs foi medido por ensaio de quimioluminescência dependente de lucigenina ou de luminol (QLlucPMN e QLlumPMN, respectivamente). Observou-se que as 3-fenilcumarinas contendo o grupo substituinte 3,4-metilenodioxi e o grupo substituinte 6,7-orto-diidroxi (C13) ou 6,7-orto-diacetoxi (C13a), bem como a 3-fenilcumarina 6,7,3,4-tetraacetoxilada (C24a), apresentaram atividade inibitória maior que a quercetina (QUER) sobre a QLlucPMN e a QLlumPMN. Para as demais substâncias avaliadas, que foram tão ou menos ativas que a QUER, as características estruturais relacionadas à inibição da QLlucPMN foram um pouco diferentes daquelas relacionadas à inibição da QLlumPMN. Além disso, as 3-fenilcumarinas estudadas e a QUER não apresentaram efeito tóxico sobre os neutrófilos, avaliado pela liberação de lactato desidrogenase e pelo ensaio de exclusão ao corante Azul de Tripan, nas condições empregadas. Para as três 3-fenilcumarinas que apresentaram maior efeito inibitório sobre o metabolismo oxidativo dos neutrófilos (C13, C13a e C24a), o aumento do tempo de pré-tratamento levou a uma tendência de redução do efeito inibitório da substância C24a, mas não influenciou na atividade biológica das substâncias C13 e C13a. Essas três substâncias não interferiram na capacidade fagocítica das células, avaliada por microscopia eletrônica de transmissão. Para todas as 3-fenilcumarinas foi avaliada também a capacidade antioxidante frente ao radical livre 2,2-difenil-1-picril-hidrazil e o efeito inibitório dessas substâncias sobre a quimioluminescência produzida pela reação horseradish peroxidase-H2O2-luminol (QLHRP). Foi observado que a QUER e as 3-fenilcumarinas contendo o grupo substituinte orto-diidroxi (C13, C23, C24) tiveram atividade antioxidante e inibiram a QLHRP, mas suas análogas acetoxiladas (C13a, C23a, C24a), bem como as demais substâncias avaliadas, foram significativamente menos ativas nesses modelos experimentais não celulares. O conjunto de resultados deste trabalho sugere que as atividades biológicas das 3-fenilcumarinas estudadas foram dependentes de suas estruturas químicas, e pequenas modificações nestas podem levar a alterações significativas na magnitude de seus efeitos biológicos. Além disso, tanto a lipofilicidade das substâncias quanto a sua capacidade antioxidante parecem ser relevantes para a modulação eficiente do metabolismo oxidativo dos neutrófilos e da conseqüente lesão tecidual.
Formation and clearance of circulating antigen-antibody complexes or immune complexes (ICs) take part in the humoral immune defense mechanisms. In some diseases, as systemic lupus erythematosus, rheumatoid arthritis and auto-immune vasculitis, an imbalance of this process occurs, leading to the ICs deposition within tissues and triggering an inflammatory reaction. The last one involves the recruitment and activation of neutrophils, which have an important role in the pathogenesis of such diseases. Neutrophil activation by ICs, via receptors for the Fc portion of IgG (FcgR) and complement receptors (CR), triggers a sort of effector functions, such phagocytosis, degranulation and the oxidative metabolism, which produces reactive oxygen species (ROS). These functions are involved in the ICs digestion, microbial killing and the inflammatory process regulation. However, the activated neutrophils release large amounts of enzymes and ROS to the extracellular milieu, contributing to the tissue damage and amplification of the inflammatory process in the IC-mediated diseases. In this work, we evaluated the modulatory effect of twenty 3-phenylcoumarin derivatives in the neutrophil functions stimulated by ICs of ovalbumin (OVA) and IgG anti-OVA. In addition, the mechanisms of action of these compounds were investigated, and the structure-activity relationship was analyzed. The IC-activated neutrophil oxidative metabolism was measured by lucigeninor luminol-dependent chemiluminescence assay (CLlucPMN and CLlumPMN, respectively).It was observed that the 3-phenylcoumarins bearing a 3,4-methylenodioxy and the 6,7-orto-dihydroxy (C13) or the 6,7-orto-diacetoxy (C13a) group, as well as the 6,7,3,4-tetraacetoxylated 3-phenylcoumarin (C24a), inhibited CLlucPMN and CLlumPMN more than quercetin (QUER). Regarding the other evaluated compounds, whose inhibitory effects were similar to or lower than QUER, the structural features related to the CLlucPMN inhibition were different from those related to the CLlumPMN inhibition. Moreover, the studied 3-phenylcoumarins and QUER had no toxic effects on neutrophils, as evaluated by lactate dehydrogenase release and Trypan Blue exclusion, under the assessed conditions. With respect to the three 3-phenylcoumarins that had the highest inhibitory effects on the neutrophil oxidative metabolism (C13, C13a and C24a), the increase of the cell pre-treatment period showed a tendency to decrease the inhibitory ability of compound C24a, but did not influence the biological activity of compounds C13 and C13a. These three compounds did not interfere in the neutrophil phagocytic ability, as evaluated by transmission electron microscopy. The antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl free radical and the inhibitory effect in the chemiluminescence generated by the horseradish peroxidase-H2O2-luminol reaction (CLHRP) were evaluated for all 3-phenylcoumarins. It was found that QUER and those 3-phenylcoumarins bearing the orto-dihydroxy group (C13, C23, C24) had antioxidant activity and inhibited the CLHRP. However, their acetoxylated analogues (C13a, C23a, C24a) and the other evaluated compounds were significantly less active on these cell-free experimental models. Taken together, the results of the present work suggest that the biological activities of the 3-phenylcounarins here investigated were dependent on their chemical structures, and small changes on the molecule can lead to significant changes on the magnitude of their biological effects. Moreover, both lipophilicity and antioxidant capacity of these compounds seem to be relevant to an efficient modulation of the neutrophil functions and the consequent tissue damage.

APA, Harvard, Vancouver, ISO, and other styles

18

Albertz, Megan Lee. "Isolation and Characterization of Protein-Tannin Complexes." Miami University Honors Theses / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1209128363.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Cousseau, Francisco Eduardo Monteiro. "Estudo das propriedades antioxidantes de complexos nitrosilados de rutênio." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/92815.

Full text

Abstract:

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Farmácia, Florianópolis, 2009
Made available in DSpace on 2012-10-24T12:39:26Z (GMT). No. of bitstreams: 1 269447.pdf: 1011841 bytes, checksum: 083f4b25bbb361ca9c1d3c1b300e3548 (MD5)
Este estudo demonstrou as propriedades antioxidantes e secundariamente a citotoxicidade de cinco complexos nitrosilados de rutênio: trans-[Ru(NH3)4(L)(NO)]Cl3 (A - D; sendo que (A) L = Cafeína, (B) L = Teofileno, (C) L = Metil-1-imidazol, (D) L = Benzoimidazol), e (E) cis-[Ru(NH3)4(NO)2]Cl3. Somente o complexo (A) apresentou significante reatividade identificada pelo método de reatividade antioxidante total (TAR) e também atividade sequestradora de radical ânion superóxido através da redução do nitro blue tetrazólio (NBT). Os complexos (A), (B), (C), (D) e (E) exibiram capacidade sequestradora de radicais hidroxilas ("OH). O potencial decresceu na respectiva ordem: D>A>B>C>E (a maioria dos valores foi menor que 15 µM). O sistema gerador de radicais hidroxilas foi o complexo Fe-ácido nitriloacético (NTA) e a oxidação da deoxirribose. A inibição da mioglobina induzida por radical monóxido de nitrogênio ("NO) foi observada para os complexos seguindo a ordem: C>B>D>E>A. A proteção da peroxidação lipídica em microssomas (MC) induzida por sistema ascorbato/H2O2 Fe3+ foi potente para os complexos (D) e (E), demonstrando valores de IC50 inferiores a 100 µM (de modo dependente da concentração). Adicionalmente, a lipoperoxidação induzida por radical ascorbila em lipossomas de fosfatidilcolina de soja foi inibida por todos os complexos, demonstrando valores de IC50 inferiores a 180 µM, no qual apresentou potencial decrescente, seguindo a ordem: D>A>C>B>E. Quando avaliado em microssomas, alguns valores foram similares. Além disto, o complexo (A) protegeu a lipoperoxidação induzida por radiação UV em MC, e somente o complexo (D) protegeu a lipoperoxidação induzida por peroxinitrito. Nenhum dos complexos demonstrou citotoxicidade em hepatócitos, mas os complexos (A) e (C) causaram a morte de células tumorais linfoblásticas de murinos (L1210).
This study shows the antioxidant and secondary the cytotoxic activity of five different ruthenium nitrosyl complexes: trans-[Ru(NH3)4(L)(NO)]Cl3 (A - D; being (A) L = Caffeine, (B) L = Theophylline, (C) L = Methyl-1-imidazole, (D) L = Benzoimidazole), and (E) cis-[Ru(NH3)4(NO)2]Cl3. Only the complex (A) (L = Caffeine) presented significant reactivity identified by the total antioxidant reactivity (TAR) assay and also potential scavenger activity of superoxide anion (O2"?) through the nitro blue tetrazolium (NBT) reduction test. The complexes (A), (B), (C), (D) and (E) showed capability to scavenge hydroxyl radicals ("OH). The respective potential decreased following the order D>A>B>C>E (most of the values of IC50 were smaller than 15 µM). The system to generate the free radical used was Fe-acetonitrile acid (NTA) and deoxyribose oxidation protection. The inhibition of myoglobin oxidation potential induced by nitrogen monoxide ("NO) was observed for the complexes following the order C>B>D>E>A. The protection of lipid peroxidation in microsomes (MC) induced by H2O2 Fe3+ ascorbate system was effective for complexes (D) and (E), with values of IC50 below 100 µM (concentration-dependent manner). In addition, lipoperoxidation promoted by ascorbyl radical in soybean phosphatidylcholine liposomes was inhibited in all samples presenting values of IC50 lower than 180 µM, in which presented potential decrease following the order D>A>C>B>E. When evaluated in microsomes, some values of IC50 were similar. Furthermore, complex (A) protected also the lipoperoxidation induced by UV radiation in MC and only complex (D) protected lipoperoxidation induced by peroxynitrite. None of the complexes showed cytotoxicity tested in hepatocytes, but the complexes (A) and (C) caused significant death to a leukemic lymphoblastic cell line (L1210).

APA, Harvard, Vancouver, ISO, and other styles

20

Santos, Péligris Henrique dos. "Efeito protetor do complexo de inclusão ácido úsnico/ß-ciclodextrina em coração isolado de rato submetido à lesão por isquemia e reperfusão." Universidade Federal de Sergipe, 2015. https://ri.ufs.br/handle/riufs/3990.

Full text

Abstract:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The interruption of the blood supply causes a change in the cellular redox status, promotes oxidative stress, tissue damage and changes in heart function. Therefore, antioxidant compounds, such as usnic acid, can prevent these changes, since they are able to re-establish cellular redox status and preserve the tissue functions. The goal of this study was to determine whether pretreatment with inclusion complex usnic acid (UA) / β-cyclodextrin (βCD) promotes cardioprotection after ischemia and reperfusion. Initially, the characterization of inclusion complex between the AU and the βCD was performed through thermogravimetry / derivative thermogravimetry (TG / DTG), differential scanning calorimetry (DSC), spectrophotometry in the infrared (FTIR) and scanning electron microscopy (MEV). After characterization, was initiated evaluating the cardioprotective effects of the inclusion complex AU / βCD. For this, Wistar rats (250-300 g) divided into two groups: the group pretreated with 50 mg / kg / day AU / βCD and pretreated with βCD group. After the pretreatment, the heart of the animal was removed to be mounted in an isolated organ perfusion system for induction of ischemia and reperfusion and were evaluated the pressure developed in the left ventricle (LVDP), heart rate (HR) and arrhythmia severity index (ASI). Also was determined in liver and heart the amount of lactate dehydrogenase (LDH) released, the formation of malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and catalase (CAT). Furthermore was verified the amount of thiol groups. The results of the physico-chemical characterization showed that UA was complexed in the cavity of βCD and may be seen in the TG weight loss in the second step, where the inclusion complex showed Δm = 19.2% while the physical mixture, Δm = 16.2%. Furthermore, it was demonstrated by SEM that the physical mixture has not interacted with βCD while the inclusion complex underwent shape change. The FTIR spectra indicated the presence of the AU in the inclusion complex in a higher proportion, in turn, the physical mixture was observed in the presence of AU lesser extent. When evaluating the cardioprotective effects of the inclusion complex AU / βCD, it was found that the pretreatment preserved LVDP (AU: 89.9% vs. 6.3 + βCD: 53.9 + 8.6%, p < 0 05) reduced the scores obtained in ASI (AU: 2.5 + 0.5 ua vs. βCD: 11.00 + 0.57 ua; p < 0.0001) and did not change the FC (AU / βCD: 78 5 + 8.6% vs βCD: 79.6 + 9.2%, p > 0.05). In biochemical assays, pretreatment reduced the amount of LDH released (AU: 0.063 + 0.026 U / L vs βCD: 0.224 + 0.036 U / L, p < 0.05) reduced the formation of MDA (AU: 5, 87 + 0.57 nmol MDA / g vs βCD: 13.02 + 1.04 nmol MDA / g, p < 0.0001), promoted the SOD activity (AU: 0.086 + 0.013 U SOD / mg protein vs. βCD: 0,050 + 0,004 U SOD / mg protein, p < 0.05) and CAT (AU: 0.054 + 0.006 ΔE / min / mg protein vs. βCD: 0.023 + 0.002 ΔE / min / mg protein; p < 0.001) and increased presence of thiol groups (AU: 97.83 + 4.23 mol / mg protein vs. βCD: 54.31 + 3.28 mol / mg protein, p < 0.0001 ). Moreover, to investigate the toxicity was not observed change in baseline levels of LDH (AU: 0.068 + 0.021 U / L vs βCD: 0.070 + 0,023U / L; p > 0.05) and MDA (AU: 8.59 + 0.27 nmol MDA / g vs βCD: 8.43 + 0.21 nmol MDA / g, p > 0.05) nor change in the SOD activity (AU: 0,025 + 0,001 U SOD / mg protein vs. βCD 0.026 + 0.001 U SOD / mg protein, p > 0.05), or CAT (AU: 0.020 + 0.004 ΔE / min / mg protein vs. βCD: 0.015 + 0.002 ΔE / min / mg protein, p > 0.05) in the liver by promoting increase of thiol groups only (AU: 245.4 + 15.6 mmol / mg protein vs. βCD: 181.8 + 14.3 mmol / mg protein , p < 0.05). Thus, it was found that the pretreatment with the inclusion complex preserved contractile function, heart protection promoted and showed no signs of toxicity.
A interrupção do suprimento sanguíneo causa alteração do status redox celular, promove estresse oxidativo, danos teciduais e alteração da função cardíaca. Diante disso, compostos antioxidantes, como o ácido úsnico, podem prevenir essas alterações, uma vez que são capazes de reestabelecer o status redox celular e de preservar as funções teciduais. Assim, o objetivo desse estudo foi verificar se o pré-tratamento com complexo de inclusão ácido úsnico (AU)/β-ciclodextrina (βCD) promove a cardioproteção após a lesão por isquemia e reperfusão. Inicialmente, foi realizada a caracterização do complexo de inclusão entre o AU e a βCD através das técnicas de termogravimetria/termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC), espectrofotometria na região do infravermelho (FTIR) e microscopia eletrônica de varredura (MEV). Após a caracterização e confirmação da formação de complexo de inclusão entre o AU e a βCD, foi iniciado a avaliação dos efeitos cardioprotetores do complexo de inclusão AU/βCD. Para tanto, foram utilizados ratos wistar (250-300 g) distribuídos em dois grupos: o grupo pré-tratado com 50 mg/kg/dia de AU/βCD e o grupo pré-tratado com βCD. Após o pré-tratamento, o coração dos animais foi removido para ser montado em sistema de perfusão de órgão isolado para a indução da lesão por isquemia e reperfusão, onde foram avaliados a pressão desenvolvida no ventrículo esquerdo (PDVE), frequência cardíaca (FC) e o índice de severidade de arritmia (ASI). Em seguida, foi determinado em fígado e coração a quantidade de lactato desidrogenase (LDH) liberada, a formação de malondialdeído (MDA), a atividade das enzimas Superóxido Dismutase (SOD) e Catalase (CAT) e verificado a quantidade de grupamentos tióis. Os resultados da caracterização físico-química demonstraram que o AU foi complexado a cavidade da βCD, podendo ser visto na TG na segunda etapa de perda de massa, onde o complexo de inclusão apresentou Δm=19,2% enquanto a mistura física, Δm=16,2%. Além disso, foi demonstrado pela MEV que a mistura física não interagiu com a βCD ao passo que o complexo de inclusão sofreu alteração de forma. Os espectros de FTIR indicaram a presença do AU no complexo de inclusão em maior proporção, por sua vez, na mistura física foi observada a presença do AU em menor proporção. Ao avaliar os efeitos cardioprotetores do complexo de inclusão AU/βCD, verificou-se que o prétratamento preservou a PDVE (AU: 89,9 + 6,3% vs βCD: 53,9 + 8,6%; p < 0,05), reduziu os escores obtidos no ASI (AU: 2,5 + 0,5 u.a. vs βCD: 11,00 + 0,57 u.a.; p < 0,0001) e não alterou a FC (AU/βCD: 78,5 + 8,6% vs βCD: 79,6 + 9,2%, p > 0,05). Nos ensaios bioquímicos, o pré-tratamento reduziu a quantidade de LDH liberada (AU: 0,063 + 0,026 U/L vs βCD: 0,224 + 0,036 U/L; p < 0,05), diminuiu a formação de MDA (AU: 5,87 + 0,57 nmol de MDA/g de tecido vs βCD: 13,02 + 1,04 nmol de MDA/g de tecido, p < 0,0001), promoveu a atividade da SOD (AU: 0,086 + 0,013 U SOD/mg de proteína vs βCD: 0,050 + 0,004 U SOD/mg de proteína; p < 0,05) e da CAT (AU: 0,054 + 0,006 ΔE/min/mg de proteína vs βCD: 0,023 + 0,002 ΔE/min/mg de proteína; p < 0,001) e aumentou a presença de grupos tióis (AU: 97,83 + 4,23 μmol/mg de proteína vs βCD: 54,31 + 3,28 μmol/mg de proteína; p < 0,0001). Ademais, ao investigar a toxicidade, não foi evidenciada alteração dos níveis basais de LDH (AU: 0,068 + 0,021 U/L vs βCD:0,070 + 0,023U/L; p > 0,05) e de MDA (AU: 8,59 + 0,27 nmol de MDA/g de tecido vs βCD: 8,43 + 0,21 nmol de MDA/g de tecido, p > 0,05) , nem alteração da atividade da SOD (AU: 0,025 + 0,001 U SOD/ mg de proteína vs βCD: 0,026 + 0,001 U SOD/mg de proteína, p > 0,05) e nem da CAT (AU: 0,020 + 0,004 ΔE/min/mg de proteína vs βCD: 0,015 + 0,002 ΔE/min/mg de proteína; p > 0,05) no tecido hepático, promovendo apenas aumento de grupamentos tióis (AU: 245,4 + 15,6 μmol/mg de proteína vs βCD: 181,8 + 14,3 μmol/mg de proteína, p < 0,05). Assim, verificou-se que o pré-tratamento com o complexo de inclusão preservou a função contrátil, promoveu cardioproteção e não mostrou sinais de toxicidade.

APA, Harvard, Vancouver, ISO, and other styles

21

Повшук, Василь Володимирович. "Нанозміцнені периклазовуглецеві вогнетриви для футерівки конвертерів з використанням комплексного антиоксиданту." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37726.

Full text

Abstract:

Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.17.11 – технологія тугоплавких неметалічних матеріалів (161 – Хімічні технології та інженерія). – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018. Дисертація присвячена розробці складів та основних технологічних параметрів отримання нанозміцнених периклазовуглецевих вогнетривів для різних зон футерівки конвертера з заданими показниками фізико-механічних властивостей і підвищеною стійкістю до дії шлаку та до окиснення. У роботі теоретично обґрунтовано і експериментально доведено можливість одержання нанозміцнених периклазовуглецевих вогнетривів шляхом синтезу наповненої наночастинами β-SiC та NiO вуглецевої матриці-основи заданої структури периклазовуглецевих вогнетривів і забезпечення її максимальної струк-турної міцності за рахунок використання оптимальних співвідношень золь-гель добавок, що модифікують фенолформальдегідну смолу, і компонентів прекурсорів нікелевого антиоксиданту. Визначено технологічні параметри одержання периклазовуглецевих вогнетривів із заданими фізико-механічними властивостями на засаді плавленого периклазу і різною кількістю графіту, шляхом використанням ЕТС-40 або його золю та солей нікелю для створення комплексного антиоксиданту Аl + SiC + Ni(NiO), що забезпечує підвищену стійкість до окиснення за рахунок утворення щільного шару із наночастин β-SiC та Ni(NiO) навколо часток графіту, розроблено безвипалювану технологію та склади магнезіального флюсу для плавки сталі в конвертері з відходів периклазовуглецевих вогнетривів футеровок конвертерів, які сприяють прискоренню наведення шлаку в конвертері та підвищенню стійкості футерівки конвертера.
Thesis for the degree of candidate of technical sciences (Ph.D.) in specialty 05.17.11 – technology of refractory nonmetallic materials (161 – chemical technologies and engineering). – National Technical University "Kharkov Polytechnic Institute", Kharkov, 2018. The thesis is devoted to the development of compositions and basic techno-logical parameters for the preparation of nano-reinforced periclase-carbon refractories for various zones of converter lining with prescribed parameters of physical and mechanical properties and increased resistance to slag and oxidation. The possibility of obtaining nano-reinforced periclase-carbon refractories by synthesis of the carbon-matrix matrix of a given structure of periclase-carbon refractories filled with nanoparticles β-SiC and NiO and ensuring its maximum structural strength due to the use of optimum sol-gel admixtures for modifying the phenol-formaldehyde resin is theoretically substantiated and experimentally proved pre-cursor components of a nickel antioxidant. The technological parameters for the production of periclase-carbon refractories with specified physic-mechanical properties based on fused periclase with different amounts of graphite were determined using ETS-40 or its sol and nickel salts to create a complex antioxidant Al + SiC + Ni(NiO), which provides enhanced resistance to oxidation due to the formation of a dense layer of β-SiC and Ni(NiO) nanoparticles around graphite particles, a non-combustion technology and magnesia flux formulations for melting steel in a converter from waste periclase-carbon refractories lining of converters that accelerate guidance in the converter slag and improve the sustainability of the converter lining.

APA, Harvard, Vancouver, ISO, and other styles

22

Повшук, Василь Володимирович. "Нанозміцнені периклазовуглецеві вогнетриви для футерівки конвертерів з використанням комплексного антиоксиданту." Thesis, НТУ "ХПІ", 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37701.

Full text

Abstract:

Дисертація на здобуття наукового ступеня кандидата технічних наук (доктора філософії) за спеціальністю 05.17.11 – технологія тугоплавких неметалічних матеріалів (161 – Хімічні технології та інженерія). – Національний технічний університет "Харківський політехнічний інститут", Харків, 2018. Дисертація присвячена розробці складів та основних технологічних параметрів отримання нанозміцнених периклазовуглецевих вогнетривів для різних зон футерівки конвертера з заданими показниками фізико-механічних властивостей і підвищеною стійкістю до дії шлаку та до окиснення. У роботі теоретично обґрунтовано і експериментально доведено можливість одержання нанозміцнених периклазовуглецевих вогнетривів шляхом синтезу наповненої наночастинами β-SiC та NiO вуглецевої матриці-основи заданої структури периклазовуглецевих вогнетривів і забезпечення її максимальної струк-турної міцності за рахунок використання оптимальних співвідношень золь-гель добавок, що модифікують фенолформальдегідну смолу, і компонентів прекурсорів нікелевого антиоксиданту. Визначено технологічні параметри одержання периклазовуглецевих вогнетривів із заданими фізико-механічними властивостями на засаді плавленого периклазу і різною кількістю графіту, шляхом використанням ЕТС-40 або його золю та солей нікелю для створення комплексного антиоксиданту Аl + SiC + Ni(NiO), що забезпечує підвищену стійкість до окиснення за рахунок утворення щільного шару із наночастин β-SiC та Ni(NiO) навколо часток графіту, розроблено безвипалювану технологію та склади магнезіального флюсу для плавки сталі в конвертері з відходів периклазовуглецевих вогнетривів футеровок конвертерів, які сприяють прискоренню наведення шлаку в конвертері та підвищенню стійкості футерівки конвертера.
Thesis for the degree of candidate of technical sciences (Ph.D.) in specialty 05.17.11 – technology of refractory nonmetallic materials (161 – chemical technologies and engineering). – National Technical University "Kharkov Polytechnic Institute", Kharkov, 2018. The thesis is devoted to the development of compositions and basic techno-logical parameters for the preparation of nano-reinforced periclase-carbon refractories for various zones of converter lining with prescribed parameters of physical and mechanical properties and increased resistance to slag and oxidation. The possibility of obtaining nano-reinforced periclase-carbon refractories by synthesis of the carbon-matrix matrix of a given structure of periclase-carbon refractories filled with nanoparticles β-SiC and NiO and ensuring its maximum structural strength due to the use of optimum sol-gel admixtures for modifying the phenol-formaldehyde resin is theoretically substantiated and experimentally proved pre-cursor components of a nickel antioxidant. The technological parameters for the production of periclase-carbon refractories with specified physic-mechanical properties based on fused periclase with different amounts of graphite were determined using ETS-40 or its sol and nickel salts to create a complex antioxidant Al + SiC + Ni(NiO), which provides enhanced resistance to oxidation due to the formation of a dense layer of β-SiC and Ni(NiO) nanoparticles around graphite particles, a non-combustion technology and magnesia flux formulations for melting steel in a converter from waste periclase-carbon refractories lining of converters that accelerate guidance in the converter slag and improve the sustainability of the converter lining.

APA, Harvard, Vancouver, ISO, and other styles

23

Santos, Nádia Alexandra Esteves. "Synthesis and evaluation of new pyrazoles, glycosylpyrazoles and rutheniumpyrazoles for antioxidant and antitumoral activity." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22521.

Full text

Abstract:

Mestrado em Biotecnologia - Biotecnologia Molecular
O cancro é a segunda maior razão de morte em Portugal, a seguir às doenças cardiovasculares. A quimioterapia continua a ser o tratamento mais utilizado e eficaz, no entanto o intervalo onde a dose é eficiente e ao mesmo tempo segura ainda é muito pequeno, podendo ser tóxico para o organismo do paciente. Dessa forma, a procura de novos agentes antitumorais eficientes e seguros tem sido crucial, tendo os pirazóis e os complexos de ruténio (II) um papel muito importante. Vários compostos contendo o anel de pirazol nas suas estruturas já demonstraram grande poder antitumoral ao inibirem enzimas cinases, tais como as aurosa cinases e as cinases dependentes de ciclina, ao induzirem a apoptose e até agindo como agentes citotóxicos contra linhas celulares tumorais. Os complexos de ruténio, por sua vez, contribuem para uma ação antitumoral mais seletiva, por terem propriedades redox ou pela incorporação de ligandos lábeis que criam locais de ligação a biomoléculas. Neste trabalho pretende-se sintetizar novos derivados de pirazol, proceder à sua glicosilação e ligação com um complexo de ruténio. Serão feitos estudos de citotoxicidade dos compostos sintetizados, para estudar o seu efeito antitumoral, e ainda testes para avaliar a sua atividade antioxidante, uma vez que a formação de espécies reativas de oxigénio, inflamação crónica e o desenvolvimento de cancro, estão muitas vezes associados. Com base nestes estudos estabelecer-se-ão importantes relações estrutura-atividade biológica que ajudarão a perceber quais os requisitos estruturais mais importantes para a atividade destes compostos.
Cancer is the second main cause of death in Portugal, after cardiovascular diseases. Chemotherapy is still the most used and effective treatment, however the window in which the dose is still safe and efficient is small and consequently it can be toxic to patient’s body. For that reason, the design and discovery of non-traditional antitumoral agents that are both efficient and safe is a key research issue, where pyrazoles and ruthenium (II) complexes have an important role. Several pyrazole-derived compounds have already demonstrated great antitumoral activity by inhibiting kinase enzymes such as aurora kinases and cyclin-dependent kinases, by inducing apoptosis and also by being cytotoxic to several cancer cell lines. Ruthenium complexes contribute to the antitumoral action by having redox properties and by being able to incorporate labile ligands that create, in vivo, active bonding sites for biomolecules. The present work aims the synthesis of new pyrazole derivatives, following by their glycosylation and incorporation into ruthenium(II) complexes. Cytotoxicity studies will be carried out to evaluate their antitumoral effect. In addition, antioxidant activities will be studied since reactive oxygen species, chronic inflammation and cancer development are often connected. Finally, important structure-activity relationships will be established, based on the results of the biological tests, highlighting the key structural requirements needed for the activity of these compounds.

APA, Harvard, Vancouver, ISO, and other styles

24

Cottrell, Catherine Elise. "Genetic variation and complex disease the examination of an X-linked disorder and a multifactorial disease /." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196182829.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Melo, Raimunda Suely Batista. "Estudo do potencial antioxidante e neuroprotetor dos nitrosilo complexos de rutênio no sistema nervoso central de ratos." reponame:Repositório Institucional da UFSC, 2012. http://repositorio.ufsc.br/xmlui/handle/123456789/93885.

Full text

Abstract:

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Neurociências, Florianópolis, 2010
Made available in DSpace on 2012-10-25T04:21:03Z (GMT). No. of bitstreams: 1 277600.pdf: 449367 bytes, checksum: daf6f2cd1fd67bc40bd0931aa13a748b (MD5)
Os complexos de rutênio (Ru) formam uma classe de compostos cujos mecanismos de potencial terapêutico ainda não foram totalmente esclarecidos. Os nitrosilo complexos de Ru Trans-cafeína, teofileno, benzoimidazol, metil-1-imidazol e o Ru-cis-nitroso desempenham um importante papel como seqüestradores de espécies reativas de oxigênio (EROs) . O objetivo de nosso trabalho foi estudar o potencial antioxidante e o possível papel neuroprotetor dos nitrosilo complexos de Ru no sistema nervoso central de rato. Observamos que os nitrosilo complexos de Ru apresentam potencial seqüestrador, prevenindo a lipoperoxidação in vitro em homogenato total de cérebro de rato frente aos insultos com os radicais . OH e ASC. . Verificamos que o nitrosilo complexo de Ru cis-nitroso (10 mM) previne a diminuição da viabilidade celular em fatias de hipocampo submetidas a 15 minutos de privação de glicose e oxigênio (PGO), seguidos de 2 horas de reperfusão, portanto apresenta efeito neuroprotetor no modelo de isquemia in vitro. Este composto foi capaz de diminuir a produção de EROs e aumentar a captação de Glu no modelo de isquemia in vitro. A proteção celular por este composto parece envolver uma menor produção de EROs e aumentar de captação de glutamato, no entanto, ainda não é possível correlacionar os efeitos de seqüestro de EROs e neuroproteção dos nitrosilo complexos de Ru. Logo são necessários mais estudos para maior entendimento destes mecanismos.
The complexes of ruthenium (Ru) are a class of compounds whose mechanisms of therapeutic potential have not been fully clarified. The nitrosyl complexes Ru Transcaffeine, theofilene, benzimmidazole, methyl-1-immidazole and Ru-cis-nitroso play an important role as scavengers of reactive oxygen species (ROS). The aim of our work was to study the antioxidant potential and possible neuroprotective role of nitrosyl complexes of Ru in the central nervous system of rats. We observe that the nitrosyl complexes of Ru prevent lipid peroxidation induced by the radicals .OH and ASC . in vitro in total homogenate of rat brain. We found that the nitrosyl complex Ru-cisnitroso (10mM) prevents the decrease in cell viability in hippocampal slices subjected to 15 minutes of deprivation of oxygen and glucose followed by 2 hours of reperfusion. Therefore, it presents neuroprotective effect in ischemia model in vitro. This compound was able to decrease the production of ROS and increase the glutamate uptake in the ischemia in vitro. The cellular protection promoted by this compound may be related to its effect of decreasing the production of ROS and increasing glutamate uptake, although it is not yet possible to correlate the effects of ROS sequestration and neuroprotection of nitrosyl complexes of Ru. Therefore further studies are needed to understand these neuroprotective mechanisms.

APA, Harvard, Vancouver, ISO, and other styles

26

SANTOS, Gérsika Bitencourt. "Ação do nitróxido tempol sobre a atividade do complexo enzimático NADPH oxidase (Nox2) em neutrófilos." Universidade Federal de Alfenas, 2016. https://bdtd.unifal-mg.edu.br:8443/handle/tede/854.

Full text

Abstract:

A identificação de novos alvos para controlar o processo inflamatório é, provavelmente, o principal desafio que dificulta o desenvolvimento de novas drogas anti-inflamatórias. Assim, a modulação das vias de sinalização intracelulares em fagócitos desponta como uma forma interessante de alcançar este objetivo. No entanto, isso pode trazer como consequência a diminuição da defesa do hospedeiro contra patógenos. Este estudo teve como objetivo examinar se o nitróxido 4-hidroxi-2,2,6,6-tetrametil-1-piperidiniloxi (Tempol) exerce efeito sobre produção de oxidantes por neutrófilos inflamatórios através da regulação da atividade de proteínas quinases e da proteína dissulfeto isomerase (PDI), uma chaperona cujos sítios ativos contêm o motivo Cys-Gly-His-Cys (CXXC) e está envolvida na montagem do complexo enzimático NADPH oxidase (Nox2) de fagócitos. Vias bioquímicas diferentes foram ativadas para a liberação de espécies reativas de oxigênio por neutrófilos inflamatórios, e, paralelamente, a atividade de proteínas quinases foi determinada sob efeito de Tempol nos fagócitos. O nitróxido inibiu significativamente o burst oxidativo dos neutrófilos de maneira dependente da concentração. Este efeito foi detectado pelo consumo de oxigênio, onde a IC50 encontrada foi de 45±4 μM. Utilizando-se ensaios de quimioluminescência dependente de luminol ou de isoluminol, mostramos que o Tempol provocou um atraso no período de resposta latente da ativação de Nox2 dos neutrófilos sob diferentes estímulos. Coerentemente, o nitróxido inibiu a atividade de proteínas quinases de neutrófilos estimuladas por diferentes vias bioquímicas, como quantificado por ensaios quimioluminescentes e por teste dot blot. Nas mesmas condições, Tempol reduziu a atividade fungicida de neutrófilos contra Candida albicans. Na presença de Tempol a atividade redutase de PDI foi reversivelmente afetada tanto in vitro como em neutrófilos inflamatórios estimulados, cuja IC50 de 35±3,3 μM foi calculada através de metodologia de espectrofluorescência. Esta atividade inibitória foi confirmada com o método espectrofotométrico de enovelamento de insulina. Foi utilizada PDI recombinante para ser estudado o mecanismo de inibição que o Tempol exerce sobre a esta tiol óxido-redutase, através de espectrometria de massa. Na análise da proteína total, 1 e 4 moléculas de Tempol foram detectadas ligadas à proteína. No entanto, somente uma molécula do nitróxido foi encontrada ligada covalentemente à PDI. Mais especificamente, a Cys400 foi modificada por Tempol. Em conjunto, os resultados revelam um novo mecanismo do Tempol sobre a regulação de enzimas associadas à atividade do complexo Nox2 de neutrófilos inflamatórios, os quais apresentam aplicações clínicas potenciais para intervenção terapêutica em processos patológicos. Entretanto, o possível uso do Tempol como agente anti-inflamatório deve ser cauteloso, uma vez que este nitróxido diminuiu a resposta microbicida de neutrófilos.
The identification of new targets for controlling inflammatory processes is, almost certainly, the major challenge that hampers the development of new anti-inflammatory drugs. Thus, the modulation of intracellular signaling pathways in phagocytes emerges as an interesting way to achieve this goal. However, this strategy can bring the effect of lowering the host defense against pathogens. This study aimed to examine whether the nitroxide 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyloxy (Tempol) has an effect on production of oxidants by inflammatory neutrophils through regulation of protein kinase activity and protein disulfide isomerase (PDI), a chaperone whose active sites containing the motif Cys-Gly-His-Cys (CXXC) and is involved in the assembly of the NADPH oxidase enzyme complex (Nox2) on phagocytes. Different biochemical pathways were activated for the release of reactive oxygen species by inflammatory neutrophils, and, in parallel, the protein kinase activities were determined under Tempol treatment of phagocytes. The nitroxide significantly inhibited oxidative burst of neutrophils in a concentration dependent manner. This effect was detected by oxygen consumption, where the IC50 was found to be 45±4 µM. By means of chemiluminescence luminol- or isoluminol-dependent assay, we showed that Tempol caused a delay in the lag period of neutrophils Nox2 activation under different stimuli. Accordingly, the nitroxide inhibited the activity of protein kinases in neutrophils stimulated by various biochemical pathways, as quantitated by chemiluminescent assays and dot blot test. Under the same conditions, Tempol reduced neutrophil fungicidal activity against Candida albicans. In the presence of Tempol, PDI reductase activity was reversibly affected both in vitro and in stimulated inflammatory neutrophils, whose IC50 of 35±3.3 µM was calculated by fluorescent methodology. This inhibitory activity was confirmed by the spectrophotometric insulin method. Recombinant PDI was used for the purpose of studying the mechanism of inhibition that Tempol exerts on this thiol oxide reductase enzyme, by mass spectrometry. In the analysis of total protein, 1 and 4 molecules of Tempol were detected bound to the protein. However, only one molecule of the nitroxide was found covalently linked to PDI. More specifically, Cys400 has been changed by Tempol. Together, these results reveal a novel mechanism of Tempol on the regulation of enzymes associated with Nox2 complex inflammatory activity of neutrophils, which have potential clinical applications for therapeutic intervention in pathological processes. However, the promising use of Tempol as an anti-inflammatory agent must be taken with caution, since this nitroxide decreased neutrophil microbicidal response.

APA, Harvard, Vancouver, ISO, and other styles

27

Provent, Christophe. "Vers des modèles biomimétiques de métalloenzymes antioxydantes." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10048.

Full text

Abstract:

La preparation de complexes metalliques, modeles des sites actifs de la superoxyde dismutase ou de la catalase, est un enjeu important dans le domaine des therapeutiques antioxydantes. Dans cette optique, differentes series de ligands, de structures ouvertes, macrocycliques ou macrobicycliques, ont ete synthetisees et leurs complexes du cuivre (ii) ou du fer (iii) ont ete etudies. Dans une premiere partie, la complexation du cu(ii) par onze ligands macrocycliques ou a chaine ouverte, a quatre sites de coordination azotes ou soufres (n#2s#2, n#3s), a ete etudiee par differentes methodes spectroscopiques (uv-visible, rpe) et des mesures electrochimiques ont ete effectuees. L'influence de la taille des cycles chelatants et de la nature des atomes donneurs sur le potentiel redox et sur la geometrie des complexes a ainsi ete mise en evidence. Certains complexes soufres possedent une bonne activite sod in vitro, mais la perdent en presence de serumalbumine. Dans une seconde partie, les strategies de preparation de modeles synthetiques non porphyriniques de catalase, pouvant complexer le fer soit sous forme d'acetylacetonates, soit sous forme de macrobicycles tetrazazote, sont decrites. De nombreuses syntheses originales ont ete realisees: protection-deprotection de 1,3-dicetones, double condensation de reactifs de wittig fonctionnalises, essais de macrobicyclisation avec ni#2#+ comme gabarit. Une serie de cinq complexes fe(iii)-bisacac a ete identifiee par spectrometrie de masse (fab) et leur stoechiometrie verifiee par spectrophotometrie uv-visible. Leur formation en absence de base semble la plus favorable pour l'obtention de complexes mononucleaires. L'activite catalase de ces complexes s'est averee assez faible

APA, Harvard, Vancouver, ISO, and other styles

28

Salvador, Cátia Sofia Clemente. "Caracterização de cogumelos silvestres da espécie Amanita ponderosa: produção de metabolitos com atividade biológica." Doctoral thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/13391.

Full text

Abstract:

Amanita ponderosa é uma espécie de cogumelos silvestres, comestível, característica de alguns microclimas mediterrânicos, existente na Península Ibérica. Neste estudo, avaliaram-se as propriedades biológicas e toxicológicas destes cogumelos e culturas, com vista a valorizar o seu potencial biotecnológico. Desenvolveu-se também uma metodologia de monitorização, utilizando técnicas de microanálise e imunológicas para screening e análise da especificidade de produção dos compostos bioativos. Os corpos de frutificação apresentaram um relevante conteúdo mineral e um perfil molecular correlacionável com o local de colheita. Tanto os cogumelos como as culturas e seus extratos revelaram baixa toxicidade, in vitro e in vivo, apresentaram propriedades antioxidantes, capacidade hepatoprotetora e efeito antiproliferativo em células MDA-MB-231. Estes resultados sugerem que A. ponderosa e/ou os seus extratos podem constituir uma importante fonte de compostos bioativos, com potencial valor nutracêutico e medicinal, podendo ser utilizados como suplementos alimentares, coadjuvantes no tratamento de doenças hepáticas e/ou tumorais; Characterisation of Amanita ponderosa wild mushrooms: production of metabolites with biological activity Abstract: Amanita ponderosa is a species of wild edible mushrooms that grows in some Mediterranean microclimates in the Iberian Peninsula. In this study, we evaluated the biological and toxicological properties of these mushrooms and cultures, in order to enhance their biotechnological potential. A monitoring methodology was also developed using microanalysis and immunological techniques, for screening and specificity evaluation of bioactive compounds production. The fruiting bodies presented a relevant mineral content and a characteristic molecular profile correlated with the geographical location. Either mushrooms or cultures and extracts have shown low toxicity in vitro and in vivo, and presented antioxidant properties, hepatoprotective effect and MDA-MB-231 antiproliferative activity. These results suggest that A. ponderosa and their extracts may constitute an important source of bioactive compounds with antioxidant benefits, nutraceutical potential and medicinal value, that can be used as dietetic supplements and as co-adjuvant of liver and cancer disease treatments.

APA, Harvard, Vancouver, ISO, and other styles

29

Tarushi, Alketa, Chrisoula Kakoulidou, Catherine P. Raptopoulou, Vassilis Psycharis, Dimitris P. Kessissoglou, Ioanna Zoi, Athanasios N. Papadopoulos, and George Psomas. "Zinc complexes of diflunisal: Synthesis, characterization, structure, antioxidant activity, and in vitro and in silico study of the interaction with DNA and albumins." ELSEVIER SCIENCE INC, 2017. http://hdl.handle.net/10150/623572.

Full text

Abstract:

From the reaction of ZnCl2 with the non-steroidal anti-inflammatory drug diflunisal (Hdifl), complex [Zn(difl-O)(2)(MeOH)(4)], 1 was formed, while in the presence of a N,N'-donor heterocyclic ligand 2,2'-bipyridylamine (bipyam), 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) and 2,2'-dipyridylketone oxime (Hpko), the complexes [Zn(difl-O,O')(2)(bipyam)], 2, [Zn(difl-O,O')(2)(bipy)], 3, [Zn(difl-O,O')(2)(phen)], 4 and [Zn(difl-O)2(Hpko)(2)], 5 were isolated, respectively. The complexes were characterized by physicochemical and spectroscopic techniques and the crystal structures of complexes 2, 3 and 5 were determined by X-ray crystallography. The ability of the complexes to scavenge 1,1-diphenyl-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) and hydroxyl radicals and to inhibit soybean lipoxygenase was studied and the complexes were more active than free Hdifl. The interaction of the complexes with serum albumins was monitored by fluorescence emission spectroscopy and the corresponding binding constants were calculated. UV-vis spectroscopy, viscosity measurements and fluorescence emission spectroscopy for the competitive studies of the complexes with ethidium bromide were employed to investigate the interaction of the complexes with calf-thymus DNA and revealed intercalation as the most possible DNA-binding mode. Computational techniques were used to identify possible binding sites of albumins and DNA, and determine the druggability of human and bovine serum albumins with the five novel complexes. The majority of the complexes are stronger binders than the free Hdifl. This is the first study incorporating experimental and computational results to explore the binding activity of metal-NSAID complexes with DNA and serum albumins, suggesting their application as potential metallodrugs.

APA, Harvard, Vancouver, ISO, and other styles

30

Sandoval, Acuña Cristián. "Inhibición del complejo i como un posible mecanismo del daño oxidativo, mitocondrial y celular inducido por anti-inflamatorios no-esteroidales." Tesis, Universidad de Chile, 2011. http://www.repositorio.uchile.cl/handle/2250/112113.

Full text

Abstract:

Los Anti-Inflamatorios No-Esteroidales (AINEs) son fármacos de estructura química heterogénea que tienen en común una acción anti-inflamatoria, anti-pirética y analgésica. Su mecanismo de acción comprende la inhibición de la enzima COX-2, responsable de la síntesis de prostaglandinas pro-inflamatorias. A pesar de su amplio uso y prescripción, los AINEs presentan importantes efectos secundarios a nivel gastrointestinal (GI). Si bien dichos efectos están parcialmente asociados a la inhibición de la isoforma COX-1, recientemente se ha postulado que, adicionalmente, la toxicidad de los AINEs implicaría una disfunción mitocondrial conducente a una caída en los niveles de ATP celular. Lo anterior desencadenaría un aumento de la permeabilidad del epitelio GI. Un evento importante en la síntesis de ATP mitocondrial es la transferencia de electrones a través de la cadena transportadora; lo anterior genera un gradiente de protones necesario para la fosforilación oxidativa. Siendo el complejo I un punto de entrada en la CTE, su inhibición redundaría no solo en una caída de ATP sino también en una mayor producción de anión superóxido (O2·-), lo que podría resultar en un incremento en el tenor oxidativo de la célula, conduciendo eventualmente a una pérdida de la viabilidad celular. Resultados recientemente obtenidos en el laboratorio en el que se desarrolló la presente tesis muestran que el AINE indometacina sería capaz de inhibir el Cx-I e incrementar la formación de O2·-. Un objetivo mayor de la presente tesis fue investigar si dicha inhibición es también observable con otros AINEs de estructura química diferente, como diclofenaco, piroxicam, ibuprofeno y aspirina. Los resultados obtenidos dan cuenta de que todos los AINEs testeados son capaces de inhibir el complejo I e incrementar la producción de superóxido. Dicha inhibición se demostró tanto en mitocondrias aisladas como en células Caco-2 expuestas a tales agentes. Los AINEs también incrementaron el tenor oxidativo y disminuyeron la viabilidad de células Caco-2. Desde un punto de vista mecanístico se observó que la inhibición del complejo I inducida por los diversos AINEs es totalmente reversible y susceptible a la competencia por parte de coenzima Q. A la luz de antecedentes que sugieren un potencial gastroprotector del flavonoide quercetina, y por ser éste capaz de acumularse preferentemente en la mitocondria, se estudió la capacidad que tendría quercetina para contrarrestar la inhibición del complejo I inducida por los AINEs y el incremento en los parámetros oxidativos que se desprenden de dicha inhibición. Tanto en mitocondrias aisladas como en células Caco-2 expuestas a AINEs, se comprobó que quercetina es capaz de proteger frente a la inhibición del complejo I y frente al aumento en la producción de superóxido mitocondrial inducidos por AINEs. Además, en células Caco-2, quercetina previno el aumento en el tenor oxidativo y la disminución en la viabilidad celular observada tras la exposición de dichas células a los diversos AINEs. Finalmente se estableció que, además de proteger contra la inhibición del complejo I, quercetina posee, aún a muy bajas concentraciones, la capacidad para actuar como un mimético de coenzima Q; en efecto, se estableció que quercetina permite el flujo normal de electrones, tanto a nivel del complejo I como entre los complejos I y III, y a lo largo de toda la cadena transportadora de electrones. En su conjunto, los resultados expuestos no solo dan cuenta de un posible mecanismo mediante el cual los AINEs inducirían toxicidad mitocondrial y celular, sino además, basado en la propuesta acerca del rol que supone la inhibición del complejo I en el desarrollo de la toxicidad de dichos agentes, la presente investigación sienta antecedentes experimentales acerca del potencial mecanismo que subyacería a un acción gastro-protectora de quercetina. Esto último se desprende de la evidencia en torno a la capacidad que tiene quercetina para prevenir la inhibición del complejo I inducida por los AINEs y para asegurar, además, a través de una acción “mimética de coenzima Q” el correcto funcionamiento de la cadena de transporte de electrones.

APA, Harvard, Vancouver, ISO, and other styles

31

Pereira, Ana Bárbara Ferreira Neves Quatorze. "Flavonoid-cyclodextrin complexes and their incorporation in milk products." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15325.

Full text

Abstract:

Mestrado em Bioquímica - Bioquímica Alimentar
The presented work describes the inclusion of the flavonoid quercetin into β and γ cyclodextrins and the subsequent incorporation of such complexes into a dairy product — fresh cheese. The characterization of the complexes was made using various techniques, and antioxidant assays were also performed to assess their antioxidant and anti-lipid peroxidation capacity in comparison to quercetin. The incorporation of the complexes in fresh cheese resulted in the modification of some of the characteristics of the food product, having these also presented promising antioxidant capacity.
O trabalho apresentado descreve a inclusão do flavonóide quercetina nas ciclodextrinas β e γ, com posterior incorporação dos complexos em laticínios, nomeadamente queijo fresco. A caracterização dos complexos de inclusão foi feita utilizando várias técnicas, tendo sido também realizados ensaios antioxidantes para avaliar a sua capacidade antioxidante e de anti-peroxidação lipídica, em comparação com a quercetina. A incorporação dos complexos no queijo fresco resultou na modificação de algumas características do produto alimentar, tendo estes complexos também apresentado uma promissora capacidade antioxidante.

APA, Harvard, Vancouver, ISO, and other styles

32

Vasquez, Gonzales Alan Anthony. "Actividad antioxidante y antimicrobiana in vitro del complejo de inclusión del aceite esencial de Schinus molle con 2 tipos de ciclodextrinas." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2021. https://hdl.handle.net/20.500.12672/16618.

Full text

Abstract:

Determina la composición del AESM y; la actividad antioxidante y antimicrobiana en complejos de inclusión con β-ciclodextrina (BCD) y Hidroxipropil-β-ciclodextrina (HBCD). Las hojas de Schinus molle fueron recolectadas del distrito de Huaraz, Ancash, Perú en diciembre del 2018. La extracción del AESM se realizó mediante hidrodestilación, la composición del AESM se determinó por cromatografía de gases/espectrometría de masas. Se prepararon complejos de inclusión del AESM con BCD y HBCD mediante el método de co-precipitación. En los complejos formados se evaluó la actividad antioxidante por el método ABTS y ORACFL, y la actividad antimicrobiana mediante los métodos de difusión en pozo de agar y la microdilución con resazurina, en todos los ensayos se utilizó como control el AESM sin complejar. Encuentra que en el análisis de la composición del AESM se detectaron 45 componentes, destacando α-felandreno, δ-cadineno, D-limoneno, α-cadinol y βfelandreno. El ensayo ABTS de AESM, BCD y HBCD arrojó un resultado de 16.44, 31.35 y 27.06 µmol TE/g, respectivamente; y en el ensayo ORAC fue 12.49, 12,69 y 13.59 µmol TE/g, respectivamente. La concentración mínima inhibitoria del AESM para Staphylococcus aureus ATCC 6638, Staphylococcus epidermidis ATCC 12228, Bacillus subtilis ATCC 6633 y Salmonella sp. fue de 1000, 500, 500, 8000 μg/mL, respectivamente. Concluye que la composición del aceite esencial de Schinus molle es similar a muestras de Latinoamérica, pero no es igual a otras muestras peruanas. Los complejos de inclusión con BCD y HBCD tuvieron una mayor actividad antioxidante y una menor actividad antimicrobiana que el AESM solo.

APA, Harvard, Vancouver, ISO, and other styles

33

Oliveira, Regina Maria Mendes. "Novos complexos de Ru(II) e Mg(II) com flavonóides : atividade tóxica, sítios ativos e mecanismos de ação." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/6241.

Full text

Abstract:

Made available in DSpace on 2016-06-02T20:34:37Z (GMT). No. of bitstreams: 1 4690.pdf: 8351408 bytes, checksum: 9d7202fba29b8aaff5f2e0dda2ac0f61 (MD5) Previous issue date: 2012-11-09
Financiadora de Estudos e Projetos
The use of pesticides in agriculture, in order to enhance and ensure food production for a growing population has led to many concerns about risks to human health and the environment. Therefore, search for new strategies which seek a safer alternative is very important. With this aim, herein we describe new ruthenium(II) and magnesium(II) complexes containing phenanthroline and flavonoids (hesperidin, hesperetin, naringin or naringenin) ligand, These complexes were synthesized and characterized by elemental analysis (C,H,N), atomic absorption and ESI-MS(+). The structures were investigated by computational calculation and 1H, 13C NMR spectroscopic techniques. The complexes are stable in solid state, in most of the organic solvents tested and at various pH values. They are more hydrosoluble and liposoluble than the free flavonoides. The insecticidal activity bioassay against the leafcutting ants Atta sexdens rubropilosa demonstrated that the complexes show a delayed kill action. The activity of the Electrophorus electricus AChE enzyme was moderately inhibited by the Ru2+ complexes whereas the Mg2+ complexes were powerfull inhibitors only against AChE of Atta sexdens rubropilosa, indicating their high selectivity to insects. Further, the complexes are essentially non-toxic to the aquatic bacterium Vibrio fischeri and to human HeLa cells. The Mg2+ complexes presented unique properties: (i) in the electrochemical experiments in aqueous solution was observed the formation of a cyclic mechanism stable involving neutral, ionic and radical species; (ii) are better scavenger superoxide radical than the free flavonóides; (iii) presents a strong blue fluorescence. They act as an on/off fluorescent switch through the changing of the medium, solvents and pH. The fluorescence observed by confocal microscopy allowed to detect the high absorption of the magnesium complexes in the HeLa cells. Overall, the physicochemical and biological properties observed for Ru2+ and Mg2+ complexes opens new frontiers of application for these compounds in various areas of science such as agriculture, medicine, and optical materials.
O uso de pesticidas na agricultura com a finalidade de aumentar e assegurar a produção de alimentos para uma população mundial crescente tem gerado preocupações quanto aos riscos para a saúde humana e ao meio ambiente. Por isso, pesquisas por novas estratégias que buscam uma alternativa mais segura são importantes. Com este objetivo, neste trabalho desenvolveu-se novos complexos de rutênio(II) e magnésio(II) contendo os ligantes fenantrolina e os flavonóides (hesperidina, hesperetina, naringina ou naringenina) coordenados ao centro metálico. Os complexos foram sintetizados e caracterizados por análise elementar de C,H,N, absorção atômica e ESI-MS(+). As estruturas foram investigadas por cálculos computacionais e espectroscopia de RMN de 1H e 13C NMR. Os complexos são estáveis no estado sólido, na maioria dos solventes orgânicos testados e em vários pH's e, são mais hidrosolúveis e liposolúveis que o flavonóides livres. Os complexos apresentaram atividade inseticida frente às formigas cortadeiras Atta sexdens rubropilosa com um modo de ação lento. A atividade da enzima AChE foi moderadamente inibida por complexos de Ru2+, enquanto os complexos de Mg2+ foram inibidores potentes somente para a enzima colinesterase de Atta sexdesns rubropilosa, indicando alta seletividade para insetos. Além do mais, os compostos são essencialmente não tóxicos para a bactéria aquática Vibrio fischeri e para células HeLa. Os complexos de Mg2+ apresentaram algumas propriedades que merecem ser destacadas: (i) nos experimentos eletroquímicos em solução aquosa observou-se a formação de um mecanismo cíclico e estável envolvendo espécies neutras, iônicas e radicalares; (ii) foram melhores sequestradores do radical superóxido em comparação aos flavonóides livres; (iii) e apresentaram fluorescência azul intensa fortemente dependente do meio, podendo atuar como sistemas fluorescentes do tipo "on/off" em função do solvente e em função do pH. A fluorescência permitiu detectar por microscopia confocal a alta absorção dos complexos de magnésio nas células HeLa. No conjunto, as propriedades físico-químicas e biológicas observadas para os complexos de Ru2+ e Mg2+ abrem novas fronteiras de aplicação para estes compostos nas diversas áreas da ciência como agricultura, medicina e materiais ópticos.

APA, Harvard, Vancouver, ISO, and other styles

34

Анан'єва, Валерія Вікторівна. "Технологія майонезних соусів підвищеної біологічної цінності." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31736.

Full text

Abstract:

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.18.06 – технологія жирів, ефірних масел і парфумерно-косметичних продуктів. – Національний технічний університет "Харківський політехнічний інститут" Міністерства освіти і науки України, Харків, 2017. Дисертація присвячена науковому обґрунтуванню та розробці технології майонезних соусів підвищеної біологічної цінності. Обгрунтовано склад купажованої жирової основи для виробництва майонезних соусів підвищеної біологічної цінності. Запропоновано і обгрунтовано вибір рослинної сировини для введення в рецептуру емульсійної продукції підвищеної біологічної цінності. Встановлено кількісні залежності вмісту поліфенолів в порошку шкірки винограду двох сортів від взаємного впливу температури і часу зберігання. Обґрунтовано раціональні температурні параметри і концентрація оцтової кислоти для переводу протопектинів порошку виноградної шкірки в розчинний стан і зміни структурно-механічних властивостей майонезних соусів з додаванням даного виду рослинної сировини. Обґрунтовано і розроблено комплексний загусник некрохмальної природи для виробництва емульсійної продукції підвищеної біологічної цінності. Визначено кількісні залежності ефективної в'язкості емульсії від концентрації складових загусника. Визначено кількісні залежності смакових якостей емульсії від концентрації складових комплексного підкислювача з мінімальним вмістом оцтової кислоти і максимально можливим вмістом цитринової та яблучної кислот для створення характерного ненав'язливого кислого присмаку. Знайдено технологічне рішення щодо зниження показників мікробіологічного та окиснювального псування при зберіганні майонезних соусів без додавання штучних антиоксидантів і консервантів. Запропоновано структурну схему виробництва майонезних соусів підвищеної біологічної цінності.
Dissertation for a candidate degree of technical sciences (Ph.D.) by speciality 05.18.06 – fats, essential oils and parfume-cosmetic products technology. National Technical University "Kharkov Polytechnic Institute" Ministry of Education and Science of Ukraine, Kharkov, 2017. The dissertation is devoted to the scientific substantiation and development of the mayonnaise sauces with enhanced biological value technology. Was substantiated the composition of blended oil for the production mayonnaise sauces with enhanced biological value. It was proposed and proved choice of vegetable raw materials for the compounding of emulsion production with enhanced biological value. Established quantitative dependences of the content of polyphenols in grapes skin powder of two varieties from mutual influence of temperature and storage time. Were substantiated the rational parameters of temperature and concentration of acetic acid for transferring from protopectin of grape skin powder to soluble form and changes in the structural and mechanical properties of the mayonnaise sauce with the addition of this species of plant raw materials. Substantiated and developed a сomplex thickener of non-starch nature for the production emulsion products with enhanced biological value. Was defined the quantitative dependence of the effective viscosity and stability of the emulsion from the thickener components concentration. Was defined the quantitative dependences of tastes of an emulsion on concentration of components of a complex acidifier with the minimum content of an acetic acid and the greatest possible content of citric and malic acids for creation of the reference unobtrusive sour smack. Was detected the technology decision for decrease of indexes of microbiological and oxidative spoilage at storage mayonnaise sauces without addition of syntetic antioxidants and preservatives. Was proposed the structural diagram of the production of mayonnaise sauces with enhanced biological value.

APA, Harvard, Vancouver, ISO, and other styles

35

Анан'єва, Валерія Вікторівна. "Технологія майонезних соусів підвищеної біологічної цінності." Thesis, НТУ "ХПІ", 2017. http://repository.kpi.kharkov.ua/handle/KhPI-Press/31735.

Full text

Abstract:

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.18.06 – технологія жирів, ефірних масел і парфумерно-косметичних продуктів. – Національний технічний університет "Харківський політехнічний інститут" Міністерства освіти і науки України, Харків, 2017. Дисертація присвячена науковому обґрунтуванню та розробці технології майонезних соусів підвищеної біологічної цінності. Обгрунтовано склад купажованої жирової основи для виробництва майонезних соусів підвищеної біологічної цінності. Запропоновано і обгрунтовано вибір рослинної сировини для введення в рецептуру емульсійної продукції підвищеної біологічної цінності. Встановлено кількісні залежності вмісту поліфенолів в порошку шкірки винограду двох сортів від взаємного впливу температури і часу зберігання. Обґрунтовано раціональні температурні параметри і концентрація оцтової кислоти для переводу протопектинів порошку виноградної шкірки в розчинний стан і зміни структурно-механічних властивостей майонезних соусів з додаванням даного виду рослинної сировини. Обґрунтовано і розроблено комплексний загусник некрохмальної природи для виробництва емульсійної продукції підвищеної біологічної цінності. Визначено кількісні залежності ефективної в'язкості емульсії від концентрації складових загусника. Визначено кількісні залежності смакових якостей емульсії від концентрації складових комплексного підкислювача з мінімальним вмістом оцтової кислоти і максимально можливим вмістом цитринової та яблучної кислот для створення характерного ненав'язливого кислого присмаку. Знайдено технологічне рішення щодо зниження показників мікробіологічного та окиснювального псування при зберіганні майонезних соусів без додавання штучних антиоксидантів і консервантів. Запропоновано структурну схему виробництва майонезних соусів підвищеної біологічної цінності.
Dissertation for a candidate degree of technical sciences (Ph.D.) by speciality 05.18.06 – fats, essential oils and parfume-cosmetic products technology. National Technical University "Kharkov Polytechnic Institute" Ministry of Education and Science of Ukraine, Kharkov, 2017. The dissertation is devoted to the scientific substantiation and development of the mayonnaise sauces with enhanced biological value technology. Was substantiated the composition of blended oil for the production mayonnaise sauces with enhanced biological value. It was proposed and proved choice of vegetable raw materials for the compounding of emulsion production with enhanced biological value. Established quantitative dependences of the content of polyphenols in grapes skin powder of two varieties from mutual influence of temperature and storage time. Were substantiated the rational parameters of temperature and concentration of acetic acid for transferring from protopectin of grape skin powder to soluble form and changes in the structural and mechanical properties of the mayonnaise sauce with the addition of this species of plant raw materials. Substantiated and developed a сomplex thickener of non-starch nature for the production emulsion products with enhanced biological value. Was defined the quantitative dependence of the effective viscosity and stability of the emulsion from the thickener components concentration. Was defined the quantitative dependences of tastes of an emulsion on concentration of components of a complex acidifier with the minimum content of an acetic acid and the greatest possible content of citric and malic acids for creation of the reference unobtrusive sour smack. Was detected the technology decision for decrease of indexes of microbiological and oxidative spoilage at storage mayonnaise sauces without addition of syntetic antioxidants and preservatives. Was proposed the structural diagram of the production of mayonnaise sauces with enhanced biological value.

APA, Harvard, Vancouver, ISO, and other styles

36

Kfoury, Miriana. "Préparation, caractérisation physicochimique et évaluation des propriétés biologiques de complexes d'inclusion à base de cyclodextrines : applications à des principes actifs de type phénylpropanoïdes." Thesis, Littoral, 2015. http://www.theses.fr/2015DUNK0397/document.

Full text

Abstract:

Les phénylpropanoïdes (PPs) constituent l'une des familles les plus abondantes des métabolites secondaires dans le règne végétal. Ils protègent les plantes contre les stress biotiques et abiotiques. De nos jours, les études portent sur l'utilisation des PPs comme alternatifs aux agents antimicrobiens, antioxydants et anti-inflammatoires de synthèse pour leur incorporation dans la formulation des produits alimentaires et pharmaceutiques. Cependant, l'utilisation de PPs est généralement limitée en raison de leur faible solubilité, stabilité et volatilité. L'objectif de notre travail a été d'encapsuler sept PPs dans des molécules cages, les cyclodextrines (CDs), en vue de développer des systèmes naturels et éco-compatibles ayant des applications potentielles dans les domaines alimentaire et pharmaceutique. Trois axes ont été abordés. Le premier axe a porté sur la préparation et la caractérisation des complexes d'inclusion CD/PP en solution et à l'état solide. Les techniques d'"headspace" couplé à la chromatographie en phase gazeuse (HS-CG), spectroscopie UV-visible, ¹H RMN, (2D) ROESY RMN, FTIR, DSC et de la modélisation moléculaire ont été utilisées comme outils pour la caractérisation des complexes obtenus. Des études de phase de solubilité ont été également réalisées. Le deuxième axe a porté sur l'évaluation de l'effet des CDs sur la photostabilité et la vitesse de libéralisation des PPs. Le dernier axe a été orienté vers l'étude des activités anti-radicalaire, antibactérienne et antifongique des complexes d'inclusion CD/PP. Les résultats montrent que les CDs sont capables d'encapsuler les PPs étudiés, réduire leur volatilité, augmenter leur solubilité et photostabilité ainsi que de générer des systèmes de libération prolongée. De plus, l'encapsulation conserve les propriétés antioxydante, antibactérienne et antifongique des PPS. Les résultats de cette étude suggèrent que les complexes d'inclusion des PPs avec les CDs peuvent être considérés comme outils prometteurs pour l'optimisation des formulations alimentaires et pharmaceutiques
Phenylpropanoids (PPs) are one of the largest families of plants secondary metabolites. They protect plants against biotic and abiotic stresses. Nowadays, extensive research has been dedicated to PPs aiming their use as natural alternatives to synthetic antimicrobial, antioxidant and anti-inflammatory agents in food and pharmaceutical formulations. However, PPs suffer from a low water solubility, high volatility, high light and thermal sensitivity that limit their further use. This current study aimed to encapsulate seven PPs in host cage molecules, cyclodextrins (CDs), in order to develop natural and biocompatible formulation that may find applications in food and pharmaceutical fields. It focused on three main research axes. The first part dealt with the preparation and the characterization of CD/PP inclusion complexes both in solution and in solid state. Characterizations were performed with Static-Headspace-Gas Chromatography (SH-GC), UV-Visible, ¹H NMR, (2D) ROESY NMR, FTIR, DSC and molecular modeling. These investigations were complemented with phase solubility studies. The second part was devoted to the evaluation of the effect of CDs on the PPs photostability and controlled release. The last part aimed to evaluate the CD/PP inclusion complexes as radical scavengers, antibacterial and antifungal agents. Results showed that CDs could successfully encapsulate PPs, reduce their volatility, enhance their solubility and photostability and generate controlled release system. In addition, encapsulation maintained the antioxydant, antibacterial and antifungal properties of PPs. Thus, the CD/PP inclusion complexes could be considered as a promising tool for formulation optimization

APA, Harvard, Vancouver, ISO, and other styles

37

Benabdelkader, Tarek. "Biodiversité, bioactivité et biosynthèse des composés terpéniques volatils des lavandes ailées, Lavandula stoechas sensu lato, un complexe d'espèces méditerranéennes d'intérêt pharmacologique." Phd thesis, Université Jean Monnet - Saint-Etienne, 2012. http://tel.archives-ouvertes.fr/tel-00952695.

Full text

Abstract:

Dans ce travail nous avons réalisé une évaluation de la composition et des activités biologiques des HEs extraites de L. stoechas récoltées sur 11 sites dans le nord de l'Algérie. Les HEs ont été analysées par GC/FID et GC/MS, où un total de 121 composés ont été identifiés, représentant de 69.88 à 91.2% du contenu total de l'huile. Les principaux constituants étaient le fenchone (11.27-37.48%), le camphre (1.94-21.8%), le 1,8-cinéol (0.16-8.71%) et le viridiflorol (2.89-7.38%). Les activités biologiques in vitro ont démontré que les activités de piégeage du radical DPPH et l'oxydation des lipides du couple β- carotène/acide linoléique différaient d'un facteur 8 et étaient liées à différents ensembles de molécules. Nos 11 HEs ont présenté de bonnes activités antimicrobiennes envers la plupart des 16 souches pathogènes testées à des valeurs de concentration minimale inhibitrice (CMI) allant de 0.16 à 3.5 mg/ml. A l'aide d'amorces dégénérées nous avons isolé trois ADNc en pleine longueur, LpFENS, LpPINS et LpGEAS, de feuilles de L. pedunculata. Six ADNc homologues en pleine longueur, LSFENS, LsPINS, LsGEAS, LvFENS, LvPINS et LvGEAS, ont été également isolés des feuilles de L. stoechas et L. viridis en utilisant des amorces spécifiques aux trois premiers ADNc clonés. L'expression hétérologue dans E. coli et l'analyse de l'activité catalytique par GC/MS des enzymes natives recombinantes purifiées de ces TPSs ont permis leur caractérisation fonctionnelle en tant que, α-fenchol synthases (LpFENS, LsFENS et LvFENS), α-pinène synthases (LpPINS, LsPINS et LvPINS) et germacrène A synthase (LpGEAS, LsGEAS et LvGEAS)

APA, Harvard, Vancouver, ISO, and other styles

38

Chen, Yumin. "Oxidation of Polymeric Polyphenols (Tannins) in Biologically Relevent Systems." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1089232925.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Sebaaly, Carine. "Préparation à petite et grande échelle des liposomes encapsulant l’huile essentielle de clou de girofle libre et sous forme de complexe d’inclusion dans l’hydroxypropyl-β-cyclodextrine : caractérisation des nanostructures et évaluation de leur effet antioxydant." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1003/document.

Full text

Abstract:

L'huile essentielle de clou de girofle (HECG) et son constituant majeur l'eugénol (Eug) sont reconnus pour leurs propriétés biologiques. Ces principes actifs naturels peuvent constituer des alternatifs aux agents antimicrobiens, antioxydants et anti-inflammatoires de synthèse dans les formulations alimentaires et pharmaceutiques. Cependant, leur utilisation est limitée en raison de leur faible solubilité aqueuse, volatilité et sensibilité à la lumière. Notre travail de thèse porte sur la préparation et la caractérisation des vésicules lipidiques encapsulant l'HECG et l'Eug ainsi que les complexes d'inclusion cyclodextrine/Eug. Dans une première étape, la méthode d'injection éthanolique est utilisée à l'échelle du laboratoire où les paramètres de préparation ont été optimisés. Des phospholipides naturels de soja saturés (Phospholipon 80H et Phospholipon 90H) et insaturés (Lipoid S100) ont été utilisés pour étudier l'effet de l'hydrogénation et de la composition des phospholipides sur les caractéristiques des liposomes. Les conditions optimales ont été par la suite appliquées pour préparer les liposomes à grande échelle par contacteur à membrane et à l'échelle pilote. Des résultats similaires en termes de taille, indice de polydispersité, potentiel zêta, morphologie et taux d'incorporation de phospholipides sont obtenus à petite et grande échelle. Ceci indique la reproductibilité de ces procédés de préparation. Par ailleurs, des complexes d'inclusion d'HP-β-CD/Eug et d'HP-β-CD/HECG sont préparés dans une solution aqueuse et ensuite incorporés dans les liposomes formant un système combiné « drug in cyclodextrin in liposomes, DCL ». Un système en double encapsulation (DCL2) a été également préparé où l'Eug ou l'HECG sont ajoutés dans la phase organique et leurs complexes d'inclusion dans la phase aqueuse. En comparant à une simple incorporation dans les liposomes, DCL et DCL2 améliorent le rendement d'encapsulation de l'Eug et possèdent des tailles plus petites. Les résultats ont montré que les liposomes et les DCLs sont stables et maintiennent l'activité anti-oxydante de l'Eug. De plus, les liposomes protègent l'Eug contre la dégradation induite par les rayons UVC. Les DCLs, dont la particularité est de maintenir une huile essentielle volatile dans un lyophilisat en dépit des pressions très basses appliquées, peuvent être considérés comme un système de vectorisation prometteur de l'HECG et de l'Eug permettant leur utilisation en tant qu'ingrédients dans les préparations cosmétiques, pharmaceutiques, et agroalimentaires
Clove essential oil (CEO) and its major constituent eugenol (Eug) are recognized for their biological properties. These molecules may constitute natural alternatives to synthetic antimicrobial, antioxidant, and anti-inflammatory agents in food and pharmaceutical formulations. However, CEO constituents are volatile, sensitive to light and possess low aqueous solubility, which may limit their wide applications. Our thesis focuses on the preparation and characterization of lipid vesicles encapsulating CEO, Eug and the inclusion complexes cyclodextrin/Eug. In a first step, the ethanol injection method is applied at laboratory scale where the preparation parameters have been optimized. Natural hydrogenated (Phospholipon 80H, Phospholipon 90H) and non-hydrogenated (Lipoid S100) soybean phospholipids were used to study the effect of hydrogenation and phospholipid composition on the characteristics of liposomes. Optimal conditions were then applied to prepare liposomes at large scale by membrane contactor and at pilot scale. Similar results in terms of size, polydispersity index, zeta potential, morphology and phospholipid loading rate were obtained at laboratory and large scale. This indicates the reproducibility of the preparation methods. In addition, HP-β-CD/Eug and HP- β-CD/CEO inclusion complexes were prepared in aqueous solution and were then incorporated into liposomes forming a combined system « drug in cyclodextrin in liposomes, DCL ». Double loaded liposomes (DCL2) were also prepared where CEO or Eug were added in the organic phase and their inclusion complexes in the aqueous phase. Compared to CEO and Eug loaded liposomes, DCL and DCL2 improved the loading rate of Eug and possessed smaller vesicles size. Results showed that both liposomes and DCLs are stable and maintain the antioxidant activity of Eug. In addition, liposomes protect Eug from degradation induced by UVC irradiation. DCLs, whose characteristic is to keep a volatile essential oil in a lyophilized form despite the very low applied pressures, could be considered as a promising carrier system of CEO and Eug permitting their use as ingredients in cosmetic, pharmaceutical and food industries

APA, Harvard, Vancouver, ISO, and other styles

40

Pons, Mégane. "Vers un traitement de la maladie d'Alzheimer : synthèse de nouveaux ligands multi-cibles." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR082.

Full text

Abstract:

La maladie d’Alzheimer (MA) est une maladie neurodégénérative complexe caractérisée par une perte progressive de la mémoire et de la cognition. C’est la première cause de démence chez le sujet âgé et affecte environs 4.6 millions de personnes par an, selon un rapport de l’association « Alzheimer’s disease International », le nombre de patients pourrait s’élever à 135.5 millions en 2050. Du fait de sa complexité, la MA reste incurable et seuls 4 médicaments aux vertus palliatives dont 3 visant à inhiber l’acétylcholinestérase (AChE) ont reçu une autorisation de mise sur le marché à ce jour. L’approche multi-cible parait particulièrement adaptée du fait du grand nombre de cibles potentielles de la pathologie, et du caractère multifactoriel de la maladie. Cette approche consiste à associer sur une seule molécule, plusieurs pharmacophores afin qu’ils puissent agir simultanément sur différentes cibles impliquées dans le processus neurodégénératif. Dans ce contexte, en parallèle de la resynthèse d’un ligand multi-cible conjugué alliant un inhibiteur d’AChE (IAChE) et un antioxydant, deux nouvelles familles de ligands multi-cibles conjuguées, combinant un IAChE et un agoniste des récepteurs nicotiniques α7 (α7 nAChR) ont été conçues et leur synthèse abordée. Dans le cas de la première famille, le fragment ivastigmine a été choisi pour sa capacité à inhiber de manière pseudo-irréversible l’AChE et a été conjugué à un motif quinuclidine, un puissant agoniste des α7 nAChRs impliqués dans la MA. En combinant ces deux fragments, il a été observé que les propriétés biologiques in vitro de chaque pharmacophore étaient améliorées. La structure de la seconde famille est basée sur le Donepezil, un IAChE réversible de plus forte affinité, combiné au même motif quinuclidine que dans la série précédente. Si des intermédiaires avancés ont été obtenus, un ou deux étapes restent à finaliser pour finaliser la synthèse de cette troisième famille de MTDL
Alzheimer’s disease (AD) is a complex neurodegenerative disease characterised by a progressive loss of memory and cognition. Nowadays, 4.6 million new patients are identified every year and according to the “Alzheimer’s diseases International” association, the number of patients could reach 135.5 million in 2050. Due to its complexity, AD remains uncurable and only 4 palliative drugs, of which 3 are acetylcholinesterase (AChE) inhibitors (AChEI), have been approved by FDA to date. AD being a multifactorial illness, with many potential targets involved in the pathology, the MTDL approach seems promising. This strategy associates in one single molecule, different pharmacophores (at least) acting on different targets involved in this CNS-related disorder. In this context, in parallel with the upscaled synthesis of a conjugated MTDL combining an AChEI inhibitor and an antioxidant, two new families of conjugated MTDLs associating an AChEI and a α7 nicotinic receptor (α7 nAChR) agonist have been investigated. The structure of the first family was based on a Rivastigmine scaffold, known to be a pseudo-irreversible AChE inhibitor, and a quinuclidine fragment, a potent α7 nAChR agonist. By combining these two fragments, it was brought to light that the in vitro biological properties were improved on both targets. The second family was based on a donepezil fragment, a more potent AChEI, and the same quinuclidine fragment than in the first family. Advanced intermediates have been obtained, and two last steps remain to be achieved for the completion of this third MTDL series

APA, Harvard, Vancouver, ISO, and other styles

41

Barandier, Christine. "Potentiel thérapeutique du manganèse et de l'un de ses dérivés synthétiques sur le système cardiovasculaire." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10238.

Full text

Abstract:

Le present travail qui s'inscrit dans le cadre general des etudes consacrees a la protection pharmacologique des tissus cardiaque et vasculaire au cours de la reperfusion post-ischemique, comprend deux parties principales. La premiere a ete realisee sur un modele d'ischemie/reperfusion myocardique sur un modele experimental de coeur isole de rat. Les resultats sont exprimes en termes de donnees fonctionnelles, metaboliques et ultrastructurales. La seconde partie est une etude pharmacologique menee sur un modele d'anneaux d'aorte isolee de rat et comporte essentiellement des mesures de contractilite vasculaire. Dans la premiere partie, nous avons etudie l'effet protecteur du chlorure de manganese sur la recuperation post-ischemique du myocarde. Nous avons demontre que le manganese, administre durant la phase precoce de la reperfusion, ameliore la recuperation metabolique et fonctionnelle, vraisemblablement par le biais d'une protection antioxydante de la membrane des cardiomyocytes. Nous avons egalement mis en evidence un effet protecteur du manganese administre avant la periode d'ischemie sur la fonction et l'ultrastructure du myocarde post-ischemique. Dans la seconde partie de notre travail, nous avons montre qu'euk8, un compose de type salen-manganese presentant de fortes activites sod et catalase, exerce in vitro un effet vasorelaxant dose-dependant, non medie par une simple protection antioxydante de no, mais essentiellement du a une activation de l'adenylate cyclase et de la guanylate cyclase soluble des cellules musculaires lisses vasculaires. Enfin, une etude des effets vasomoteurs du manganese nous a amenes a conclure qu'il induit une relaxation par le biais de mecanismes plus complexes qu'une simple protection antioxydante de no et qu'un simple effet antagoniste calcique direct sur les cellules musculaires lisses vasculaires.

APA, Harvard, Vancouver, ISO, and other styles

42

Hsu, Chin-Mu, and 許欽木. "Hepatotoxic Protection and Antioxidant Activity of Angelica sinensis–Hydroxylpropyl-β-cyclodextrin Complex." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/ky654y.

Full text

Abstract:

博士
中國醫藥大學
中醫學系博士班
101
Angelica sinensis (AS) is a traditional Chinese medicinal herb used extensively in the East for its hepatoprotective effects. The ingredients of AS extract have minimal solubility in water. To overcome this problem, inclusion complexes of hydroxylpropyl-β-cyclodextrin (HP-β-CD) and AS extract, AS-HP-β-CD, will be prepared by freeze-drying and subsequently characterized by thermogravimetric analysis, differential scanning calorimeter, and nuclear magnetic resonance. The major components of ferulic acid and ligustilide were confirmed by HPLC-MS assay in both AS extract and AS-HP-β-CD. Furthermore, the effect of complexing HP-β-CD with AS extract on the extract’s antioxidant activity, human hepatoma cell growth inhibition, and inhibition of carbon tetrachloride (CCl4)-induced hepatotoxicity in mice will be investigated. The results showed that the AS-HP-β-CD complex was more active than the AS extract and showed dose-dependent antioxidant activity and human hepatoma cell growth inhibition. The CCl4-treated mouse model revealed that the AS-HP-β-CD complex more effectively reduced increases in serum aspartate aminotransferase, serum alanine transferase, and hepatic malondialdehyde concentrations than the AS extract. Similarly, positive effects were also observed in histopathological specimens and in liver antioxidant enzyme activities.

APA, Harvard, Vancouver, ISO, and other styles

43

Tang, Tzu-Chia, and 湯子嘉. "Study on antioxidant of fermentation coffee bean by Complex bacteria in different brew methods." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/29717150665876464250.

Full text

Abstract:

碩士
環球科技大學
生物技術研究所
102
Coffee is one daily life of beverages, from coffee industry development has been popularized, people also followed to enhance coffee quality and taste. Indonesian civet (Musang) After a eating the coffee fruit gastrointestinal digestion, cannot digest baked coffee beans after washed, discovered the special flavor,therefore namedcivet coffee (Kapi Luwak). Arabica coffee beans this study,in the process of coffee fermentation method use of composite,and general washed coffee and Indonesian civet coffee as a comparison. Experiment results in DPPH, TEAC and Redox capacity in espresso extraction is higher than the follicular type extraction. DPPH at 2.5 mg/mL espresso fermented beans and washed beans were the highest of 75.8%, 73.95%. TEAC fermented beans in follicular type extraction highest 1.92 mmol/mg. Follicular Extraction of fermented beans at 2 mg/mL when Absorbance values higher than 0.63 nm civet coffee beans and washed beans.Metal chelating ability of extracts significant difference in two ways, concentration at 20 mg/mL for the highest espresso extraction metal chelatingability of about 80.91%.Total phenolic compounds, flavonoids, caffeine and chlorogenic acid components extracted espresso coffee beans high in the follicular type. Total phenolic content of espresso washed beans Highest 78.95 μg/mg. Flavonoid compounds espresso highest was washed beans 26.82 μg/mg. Espresso with follicular type extraction civet coffee beans content of 55.77 μg/mL and 28.48 μg/mL compared to less than fermented beans and Washed beans. Caffeine content in coffee beans with civet coffeelower in part civet digestive absorption of caffeine may be broken, caffeine is fermented beans are slightly lower than the washed beans, then microbial fermentation process may be decomposed part caffeine. Chlorogenic acid content slightly above the washed beans and fermented bean coffee beans in civet coffee beans, the highest content of espresso extraction civet coffee beans 66.45 μg/mL.The results showed espresso is better than the follicular type,And three kinds of coffee beans with antioxidant ability and antioxidant ingredients. Differences in the triangular test civet coffee and fermented coffee small, Determine the fermented coffee beans civet coffee beans taste and taste similar. The results of the evaluation in the hobby holistic fermented coffee and civet coffee the same average score was 3.11 mouthfeel slightly washed coffee.

APA, Harvard, Vancouver, ISO, and other styles

44

Wang, Shih-Chung, and 汪世崇. "The analysis of the antioxidant and anti-tumor complex in the extract of duck eggshell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/07547128606455518956.

Full text

Abstract:

碩士
國立宜蘭大學
動物科技學系碩士班
96
The duck industry is vigorously developed in Taiwan. However, the by-product of eggshell is wasted and may cause the environmental pollution. In order to re-utilize the waste to raise the economical value, we tried to extract the high valuable component from the eggshell. Based on the traditional Chinese medicine, the blue egg shell has been believed to be an important medicine-inducer. Some reports indicated that the pigment of blue egg was biliverdin. Biliverdin has been proven to be an important antioxidant, anti-mutagen and immunoregulator in physiology. We considered that there should be some antioxidants existed in blue eggshell, especially biliverdin. There were two major objectives in the present study, which were to extract the antioxidative activities of biliverdin and other substrates from blue eggshell, and to assay the anti-tumor ability of the extract. In this study, we obtain the crude extract of eggshell. The biliverdin component in the crude extract was detected by spectrophotometer and by HPLC. Also, the crude extract of blue eggshell has been proven to have the antioxidative ability to prevent the lipid peroxideation, but that of white eggshell didn’t. Moreover, the crude extract was concentrated by vacuum and then heated to be the active extract. The active extract after heating process has been found to strongly inhibit the proliferation and induce the apoptosis of liver tumor cell lines, huh 7 and Hpe G2, especially huh 7. However, the cytotoxicity was much lower to the human bone marrow cell (HBM 01) and the primary culture of mouse embryonic fibroblasts. Also, we proved that the heated eggshell extract could cause huh 7 apoptosis by triggering the pathway of Caspase-9 and Caspase-3 caused by the depolarization of mitochondria. It is the first time to find the anti-tumor complex existed in eggshell in this study. It may be valuable to develop a new anti-tumor drug from the heated extract of eggshell in the future.

APA, Harvard, Vancouver, ISO, and other styles

45

Agrawal, Manisha. "Synthesis of beta-cyclodextrin inclusion complex with a phenolic antioxidant in polyethylene film and its industrial applications." 2008. http://www.lib.ncsu.edu/theses/available/etd-07092008-101301/unrestricted/etd.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Hsu, Chih-Yu, and 許芷瑀. "Investigation of the stability and antioxidant activity in various cyclodextrins with 7‚8‚4′-Trihydroxyisoflavone inclusion complex." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/56123658814806542887.

Full text

Abstract:

碩士
高雄醫學大學
香粧品學系碩士班
105
7,8,4''-Trihydroxyisoflavone (784THIF), a secondary metabolite from daidzin, has been found many biological activities, including antioxidant and anti-inflammation. However, 784THIF has aqueous poor solubility, stability and bad bioavailability to limit its application in medicine, food and cosmetic industry. The purpose of the study is used various cyclodextrins, including α-cyclodextrin, β-cyclodextrin, γ-cyclodextrin, hydroxypropyl-β-cyclodextrin (HPBCD), as a carrier to inclusion 784THIF and investigated the improvement of aqueous solubility, stability, skin absorption and antioxidant activity. The results of the present study indicated that hydroxypropyl-β-cyclodextrin 784THIF inclusion complex (HP-784) presents the best inclusion efficiency and aqueous solubility than other cyclodextrins by improving the physicochemical properties, such as amorphous transformation, hydrogen bonding interaction with HPBCD. In addition, HP-784 also increased the in vitro skin penetration when compared with raw 784THIF and β-cyclodextrin inclusion complex (B-784). HP-784 had better photostability and thermalstability than raw 784THIF in alcohol and which can maintain the antioxidant activity of 784THIF. In conclusion, HP-784 inclusion complex may be used as an additive in cosmetic product to care skin.

APA, Harvard, Vancouver, ISO, and other styles

47

SHUAN, LIN, and 林萱. "Preparation And Antioxidant Activities Of Djulis Extract-Zein Complexes." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/6cr36f.

Full text

Abstract:

碩士
輔仁大學
食品科學系碩士班
107
Preparation and antioxidant activities of djulis extract-zein complexes Abstract Djulis (Chenopodium formosanum Koidz.) has functional ingredients, such as phenolic acid, flavonoid and rutin which have an antioxidant effect. Zein can be conjugated with some therapeutic bioactive substances to function as a carrier for microcapsules. Therefore, the aim of this study was to form djulis extract-zein complex and to determine its corresponding antioxidant activity. Djulis powder was mixed with distilled water, 60%, 75% and 95% ethanol respectively to be extracted under 30oC for 4 hours. The contents of total polyphenol, flavonoid and antioxidant activity of djulis extracts were detected. Additionally, LC-MS was used to analyze extracts and djulis-zein complex. The results showed that the amount of total phenol in 60% and 75% ethanol extracts were 42.10 ± 1.26 μg/mg and 35.91 ± 1.50 μg gallic acid equivalent/mg, respectively. The scavenging effects on ABTS•+ radical showed the EC50 values of 60% and 75% ethanol djulis extracts were 1.08 ± 0.07and 1.33 ± 0.33 mg/mL, respectively. In addition, the phenolic acids and flavonoids including quinic acid, hydroxyphenylacetic acid pentoside, vanillic acid, quercetin-3-O-(coumaroyl)-rutinoside, and rutin (quercetin-3-O-rutinoside) in 60% ethanol extract were identified by LC-MS-MS. In the FTIR results, for vanillic acid-zein, quinic acid-zein and rutin-zein complexes, the main peaks of vanillic acid, quinic acid and rutin both were shifted. Thereafter, rutin-zein complex have the highest scavenging effects on DPPH and ABTS•+ radical, with the EC50 values being 0.04 ± 0.01 and 0.38 ± 0.01 mg/mL, respectively. In conclusion, these results indicated that zein could indeed be used as a carrier of djulis extract. The rutin-zein complex had the highest antioxidant activity and thus could be useful for functional foods. Keywords: djulis, zein, complexes, phenolic acid, flavonoids, antioxidant activity

APA, Harvard, Vancouver, ISO, and other styles

48

Fokt, Olga. "Mitochondrial respiratory chain complexes and antioxidant enzymes analyses in diabetes and chronic periodontitis-derived human blood mononuclear cells." Master's thesis, 2019. http://hdl.handle.net/10316/89692.

Full text

Abstract:

Trabalho Final do Mestrado Integrado em Medicina Dentária apresentado à Faculdade de Medicina
A periodontite é uma doença crónica e inflamatória, iniciada pela presença de um biofilme bacteriano que afeta os tecidos que suportam os dentes e culmina na reabsorção óssea. A diabetes mellitus (DM) é um grupo de doenças metabólicas caracterizada por uma hiperglicemia que induz um estado pró-inflamatório excessivo. Evidências atuais apontam para uma inter-relação bidirecional entre diabetes e periodontite, que se tornou conhecida como a sexta complicação da DM e pode ser um fator de risco para a descompensação diabética. Estas patologias associam-se ao stress oxidativo devido ao aumento da produção de espécies reativas de oxigênio (ROS). Assim, neste trabalho pretendemos definir a atividade disfuncional do complexo mitocondrial I e III, dois principais produtores de ROS mitocondriais, e as atividades e níveis proteicos de antioxidantes celulares utilizando células mononucleares do sangue periférico (PBMCs) de pacientes com periodontite crônica (CP). e DM mais CP (DM-CP), quando comparados aos controlos. Os doentes e os indivíduos controlo foram selecionados através de consultas de Medicina Dentária no Centro Hospitalar da Universidade de Coimbra (CHUC), onde foram determinados os parâmetros clínicos para o diagnóstico da saúde periodontal. Analisamos as atividades enzimáticas do complexo I e III da cadeia transportadora de eletrões mitocondrial, e da citrato sintase(CS), uma enzima do ciclo do ácido cítrico / ciclo de Krebs, bem como a atividade do ciclo redox da glutationa, Mn-superóxido dismutase (SOD) / SOD2 e níveis da catalase em PBMCs isolados. Os nossos resultados demostram uma diminuição da atividade do complexo III no grupo DM-CP, e uma redução da atividade do ciclo da glutationa, diminuição dos níveis de glutationa reduzida e oxidada (GSH e GSSG) e diminuição da atividade da glutationa peroxidase (GPx) e da glutationa redutase (GRed) no grupo DM-CP. Além disso, encontramos uma tendência para níveis aumentados de acetil (K68) SOD2 e níveis proteicos reduzidos da catalase em PBMCs de pacientes com DM-CP. Estes dados indicam um potencial aumento da produção mitocondrial de ROS e redução do perfil de antioxidantes nas células sanguíneas dos DM-CP, explicando assim os níveis exacerbados de ROS no grupo DM-CP observados no nosso estudo anterior.
Periodontitis is a chronic inflammatory disease, initiated by the presence of a bacterial biofilm affecting the tissues that support the teeth and culminating in bone resorption. Diabetes mellitus (DM) is a group of metabolic diseases characterised by hyperglycaemia that induces an excessive proinflammatory state. Current evidence points to a bidirectional interrelationship between diabetes and periodontitis, which has become known as the sixth complication of DM and could be a risk factor for diabetic decompensation. These pathologies associate with oxidative stress due to increased production of reactive oxygen species (ROS). Thus, in this work we aimed to define dysfunctional activity of mitochondrial complex I and III, two major producers of mitochondrial ROS, and the activities and protein levels of cellular antioxidants using peripheral blood mononuclear cells (PBMCs) from patients with chronic periodontitis (CP) and DM plus CP (DM-CP), when compared to control individuals. Patient and control individuals were selected from dentistry appointments at the Hospital Centre of Coimbra University (CHUC) where clinical parameters for the diagnosis of periodontal health were determined. We analysed the enzyme activities of complex I and III from mitochondrial electron transport chain, and related citrate synthase, an enzyme of the citric acid/Krebs cycle, as well as the activity of glutathione redox cycle, Mn-superoxide dismutase (SOD)/SOD2 and catalase levels in isolated PBMCs. Our results show decreased activity of complex III in DM-CP group, and reduced activity of glutathione cycle, namely decreased levels of reduced and oxidized glutathione (GSH and GSSG) and diminished activities of glutathione peroxidase (GPx) and glutathione reductase (GRed) in DM-CP group. Furthermore, we found a tendency for increased levels of acetyl(K68) SOD2 and reduced protein levels of catalase in PBMCs from DM-CP patients. These data indicate potential increased mitochondrial generation of ROS and reduced antioxidant profile in blood cells from DM-CP, thus explaining exacerbated ROS levels in DM-CP group observed in our previous study.

APA, Harvard, Vancouver, ISO, and other styles

49

LU, JIA-LIN, and 呂嘉霖. "Potential Antioxidant Activity of Novel Aliphatic 1,2-Diketone Bis(thiosemicarbazone) Schiff-Base Ligands and Their Transition Metal Complexes." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/07134011897505625584.

Full text

Abstract:

碩士
南臺科技大學
化學工程與材枓工程系
105
Thiosemicarbazones (TSCs) reportedly have potential therapeutic activity and are widely applied in medicine especially in the treatment of tuberculosis. Various compounds with a TSC moiety also exhibit biological activity. In a number of cases, the transition metal complexes of TSC exhibit greater biological activity than the corresponding ligands, such as antimicrobial, antiamoebic, antitumor and anticancer activities. Hence, this observation has encouraged detailed studies on the coordination chemistry of thiosemicarbazones. Because of the aliphatic compounds are more easily metabolized than aromatic compounds in the human body. This study focuses on the syntheses of transition metal complexes derived from novel aliphatic thiosemicarbazones and their biological activity. The text was divided into four major parts: In the first part, various substituted-aliphatic 1,2-diketones were treated with different thiosmeicarbazides, such as 4-phenylthiosemicarbazide, 4-(4-methylphenyl) thiosemicarbazide and 4-ethylthiosemicarbazide to afford a serial of desired aliphatic 1,2-diketone bis(thiosemicarbazone) Schiff-bases. In the second part, the synthetheses and spectral characterization of diverse nickel complexes were discussed separately by two sections: (A) the aliphatic 1,2-diketone bis(4-phenylthiosemicarbazone) and aliphatic 1,2-diketone bis(4-(4-methylphenyl) thiosemicarbazone)Schiff-bases were treated with nickel(II) chloride hexahydrate to afford the corresponding nickel complexes; (B) the aliphatic 1,2-diketone bis (4-ethylthiosemicarbazone)ligands were treated with nickel(II) perchlorate hexahydrate in the presence of triethylamine to obtain the desired nickel complexes. In the third part, the syntheses and spectral characterization of the other transition metal complexes were studied through the reaction of 1,2-diketones bis (thiosemicarbazone) with transition palladium(II) metal ion. In the fourth part, evaluation of antioxidant activity-scavenging effect on DPPH radical has been studied. Among them, almost all the ligands exhibited the potent DPPH radical scavenging activity, comparable to the activity of vitamin E.

APA, Harvard, Vancouver, ISO, and other styles

50

Monteiro, Ana Filipa Ferreira. "Encapsulação molecular de compostos bioativos de Geranium robertianum e Rosmarinus officinalis em produtos lácteos." Master's thesis, 2021. http://hdl.handle.net/10773/31001.

Full text

Abstract:

A erva de São Roberto (Geranium robertianum) e o alecrim (Rosmarinus officinalis), plantas abundantes em Portugal, são ricas numa grande variedade de fitoquímicos, incluindo compostos fenólicos, conferindo-lhes elevado potencial para aplicações em diversas indústrias, particularmente na alimentar. Neste trabalho foram analisados os conteúdos totais de compostos fenólicos (CFT) e identificados os constituintes individuais em decocções aquosas e em extratos etanólicos (EtOH:H2O 65:35 v/v) de ambas as plantas. Em paralelo, as mesmas análises foram efetuadas em extratos aquosos purificados, obtidos por cromatografia de extração em fase sólida com cartuchos C18. De entre os extratos de G. robertianum, o aquoso purificado foi o que apresentou o maior teor de CFT: 457,9±7,96 mg EAG/g de extrato seco, exibindo uma concentração de ácido elágico de 116,9±4,6 mg/g; 5,08±0,24 mg de ácido 5-O-cafeoilquínico/g e 5,86±0,23mg de ácido gálico/g extrato seco. Por sua vez, o extrato etanólico de R. officinalis era rico em compostos de interesse como o ácido rosmarínico, carnosol e derivados de isorhamnetina (36,9±2,7, 27,9±1,38 e 5,86±0,69 mg/g extrato seco, respetivamente). Estes extratos foram escolhidos para complexação com ciclodextrina gama (γ-CD) com o objetivo de aumentar a solubilidade dos compostos bioativos de cada planta e averiguar se a inclusão confere efeito protetor sobre os mesmos. Os complexos de inclusão, γ-CD·EGR e γ-CD·ERO, foram preparados pelo método de codissolução seguido de liofilização, tendo sido caracterizados com recurso a espectroscopia de infravermelho (FTIR), difração de raios X de pós e análise termogravimétrica. Os resultados evidenciaram a natureza amorfa de γ-CD·EGR, enquanto o γ-CD·ERO se apresentou como uma nova fase microcristalina e indicadora de um complexo de inclusão com empacotamento em canal. O extrato aquoso purificado de G. robertianum e γ-CD·EGR foram utilizados para suplementação de um queijo fresco, numa concentração de 0,5% (m/m), enquanto o extrato etanólico de R. officinalis e γ-CD·ERO foram aplicados numa bebida comercial de kefir, também numa concentração de 0,5% (m/v). Em ambos os casos, os produtos lácteos enriquecidos exibiram elevada atividade antioxidante, medida pelo método de inibição do radical ABTS˙+, em comparação com as amostras não suplementadas (controlo). Este aumento foi mais evidente nas amostras suplementadas com γ-CD·EGR (1,823±0,048 mg EAA/g queijo fresco) e γ-CD·ERO (2,138±0,156 mg EAA/mL kefir) do que nas suplementadas apenas com extrato. Esta tendência foi também registada nos valores de CFT, sugerindo que a inclusão na γ-CD permitiu um aumento da solubilização dos compostos nas matrizes. A medição instrumental da cor pelo espectrómetro CM-2300d permitiu concluir que, a suplementação dos produtos lácteos com os extratos ou γ-CD·EGR/γ-CD·ERO, produz uma variação de cor superior a 5, que era facilmente visível a olho nu. As variações de pH foram, no geral, inferiores nas amostras suplementadas relativamente aos controlos.
The São Roberto herb (Geranium robertianum) and rosemary (Rosmarinus officinalis), abundant plants in Portugal, are rich in a wide variety of phytochemicals, including phenolic compounds, displaying a high potential for industrial applications, particularly in the food industry. In this work, the total phenolic compounds (TPC) and the identification of individual constituents were determined in aqueous decoctions and in ethanolic extracts (EtOH:H2O 65:35 v/v) of the two plants. The same analyses were performed on purified aqueous extracts, obtain by solid phase extraction with C18 cartridges. The purified aqueous extract of G. robertianum had the highest TPC content: 457.9±7.96 mg GAE/g dry extract, showing an ellagic acid concentration of 116.9±4.6 mg/g; 5.08±0.24 mg/g of 5-O-caffeoylquinic acid and of 5.86±0.23 mg of gallic acid/g dry extract. In turn, the ethanolic extract of R. officinalis was rich in compounds of interest such as rosmarinic acid, carnosol and isorhamnetin derivatives (36.9±2.7, 27.9±1.38 and 5.86±0.69 mg/g dry extract, respectively). These extracts were further used as guest for inclusion into γ-CD, aiming at increasing the solubility of the bioactive components and at a possible protective effect by γ-CD. The inclusion complexes, γ-CD·EGR and γ-CD·ERO were prepared by codissolution followed by freeze-drying and were characterised by infrared spectroscopy (FTIR) techniques, powder X-ray diffraction and thermogravimetric analysis. The results demonstrated that the γ-CD·EGR had an amorphous nature, whereas that of γ-CD·ERO was microcrystalline and tallies well with the family of γ-CD complexes with structural organisation into channels. The purified aqueous extract of G. robertianum and γ-CD·EGR was used to supplement fresh cheese at 0.5% (w/w), while the ethanolic extract of R. officinalis and its γ-CD complex were applied in 0.5% (m/v) in a commercial kefir drink. The fortified matrices of fresh cheese and kefir exhibited higher antioxidant activities, as measured by the ABTS˙+ radical inhibition method, in regard to non-fortified samples. The increased antioxidant activity was more noticeable in the samples fortified with γ-CD·EGR (1.823±0.048 mg EAA/g fresh cheese) and γ-CD·ERO (2.138±0.156 mg EAA/mL kefir) than in those supplemented with extracts. This was confirmed by TPC quantification, demonstrating that the presence of γ-CD allowed for the increased solubilisation of the actives in the matrices. The instrumental measurement of color by CM-2300d spectrometer showed that the supplementation of dairy products with extracts or γ-CD·EGR/ γ-CD·ERO produced a color variation higher than five, which was easily visible at the naked eye. The pH variations were, in general, lower in the supplemented samples compared to the controls.
Mestrado em Biotecnologia

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Complex antioxidant'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles