Дисертації з теми "DPPH antioxidant activity"

A atividade antioxidante de dois extratos comerciais de alecrim e chá verde foi comparada com a atividade do sintético BHA para substituição total do sintético em hambúrguer de frango. A quantificação foi determinada pelos métodos Folin-Ciocalteau, FRAP e DPPH. De acordo com as análises de atividade antioxidante, as dosagens dos extratos naturais foram determinadas, utilizando-se como base o limite de dosagem do BHA (0,01% base gordura) e aplicadas em hambúrgueres de frango: T1: Controle; T2: 0,002% BHA; T3: 0,0038% Chá Verde; T4: 0,001% Chá Verde; T5: 0,048% Alecrim; T6: 0,00186% Alecrim. Foram realizadas análises de composição centesimal e pH e análises de estabilidade no armazenamento congelado: rendimento e redução do diâmetro, índice de TBARs, cor objetiva (parâmetros L*, a* e b*) e teste sensorial de aceitação. No método Folin-Ciocalteau, das análises de atividade antioxidante, o BHA não apresentou diferença com o chá verde (p > 0,05), no método FRAP o melhor (p < 0,05) desempenho foi do BHA e no DPPH o chá verde apresentou maior atividade (p < 0,05). Os resultados de TBARS, nos hambúrgueres, mostraram diferença significativa entre as amostras e também interação amostras x tempo do armazenamento (p < 0,05), sendo que após 120 dias o teste com maior dosagem do extrato de alecrim (T5) não diferiu do sintético (T2) (0,423 e 0,369 índice de TBARs, respectivamente). No aspecto sensorial as amostras não diferiram entre si (p>0,05) nem durante todo o período de armazenamento (p > 0,05). Dentro das condições experimentais pode-se afirmar que o extrato comercial de alecrim pode substituir totalmente o antioxidante BHA em hambúrguer de frango, garantindo a mesma estabilidade oxidativa e sem interferir em sua aceitação sensorial.
The antioxidant activity of two commercial extracts, rosemary and green tea, were compared with the activity of the synthetic BHA for total replacement of the synthetic in chicken burger. The spectrometric quantification was determined by UV - VIS methods: Folin - Ciocalteu , FRAP and DPPH . In the Folin-Ciocalteau method the BHA showed no difference with green tea (p > 0.05), in the FRAP method the BHA obtained better (p < 0.05) performance and for DPPH the green tea showed greater activity (p < 0.05). According to the analysis of antioxidant activity, dosages of natural extracts were determined, using as basis the limit dosage of BHA (0.01 % fat base) and applied in chicken burgers: T1: Control, T2: 0.002 % BHA, T3: 0.0038 % Green Tea, T4: 0.001 % Green Tea, T5: 0.048 % Rosemary and T6: 0.00186 % Rosemary. Chemical-physical analysis of chemical composition and pH were made, and also stability analysis: cooking loss and reducing the diameter, TBARs index, objective color (parameters L *, a * and b *) and sensory acceptance test. The results of TBARS showed a significant difference between samples and also samples interaction x storage time (p < 0.05), after 120 days the test with higher dosage of rosemary extract (T5) did not differ from synthetic (T2) (0.423 and 0.369 TBARS index, respectively), thus better performance than the other tests. The sensory evaluation results showed that the samples did not differ during the storage period (p > 0.05). According the experimental conditions can be concluded that the commercial rosemary extract can completely replace the antioxidant BHA.

Thesis (M.Sc. (Chemistry)) -- University of Limpopo, 2016
In this study, antioxidant activity methodologies were evaluated in terms of analytical performances. The total antioxidant activity from Athrixia phylicoides leaves (Bush tea) determined using 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH•) method, cupric ion reducing power (CUPRAC) method and cyclic voltammetry (CV). Folin-Ciocalteu method was used to quantify total phenolic content (TPC) in Athrixia phylicoides leaves. The influence of chemical and physical parameters on the total phenolic content and antioxidant activity determination were investigated. Results from direct sample and crude sample were compared. Antioxidant activity and phenolic content from Athrixia phylicoides leaves were compared with those from commercialised green tea, black tea and rooibos tea using two chosen antioxidant capacity method with acceptable characteristics. Results from the evaluation of the methods demonstrated excellent recoveries (99 to 103%) consistently, good linearity within the calibration concentration range (R2 = 0.997) and repeatable low coefficient of variation < 5% were indicative of good precision except for CV method. The average total antioxidant activity of various extracts of Athrixia phylicoides leaves ranged from 0.039 to 0.122 mg/mL (EC50), 0.031 to 0.233 mg/mL (EC50) and 339 to 429 mV (anodic potential) for DPPH method, CUPRAC method and CV method, respectively. The total antioxidant activity values for each Athrixia phylicoides samples determined by CUPRAC method were higher than the values produced by DPPH and CV methods. The highest antioxidant activities in the DPPH and CUPRAC methods were found in water extracts (direct sample). However, concentrated samples for DPPH method and CV gave a different trend with the methanol extract (crude sample) displaying the highest antioxidant capacity. Increasing the infusion time only increased total antioxidant activity determined by CUPRAC method, whilst DPPH and CV methods had the highest antioxidant activity in the lowest infusion time (3 min). Even though the results are inconclusive with regard to the effect of solid to solvent ratio effect on the total antioxidant activity, 1:150 ratio and 1:100 ratio extracts for both CUPRAC and DPPH methods and for CV gave the highest antioxidant capacities, respectively. The total antioxidant activities in pure antioxidant standards and in the teas were ranked in the following order by both CUPRAC and DPPH methods: Quercetin > catechin > Trolox and Chinese green tea > Joko black tea > Athrixia phylicoides leaves > Laager rooibos tea, respectively. Comparative study showed the necessity of employing more than one method, as each method for the same sample yielded different results. CUPRAC and DPPH methods displayed higher sensitivity and repeatability as compared to the CV method with poor precision.

This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.

Mestrado em Engenharia de Viticultura e Enologia - Instituto Superior de Agronomia / Faculdade de Ciências - Universidade do Porto
The study of antioxidant activity, a quality parameter, was performed during the first year of a Lourinhã wine spirit’s ageing, through two different ageing technologies: traditional technology using 250 L barrels, and alternative technology using 1000 L stainless steel tanks with wooden staves and micro-oxygenation. In both technologies, the same types of wood were used: Limousin oak and chestnut, and mixture of them, with medium plus toasting level. The quantity of the wooden staves added to the stainless steel tanks was calculated to reproduce the surface area to volume ratio of 250 L wooden barrel, therefore, to be comparable. The tanks were provided with micro-oxygenation during the ageing period, simulating the amount of oxygen entering through the barrels. The alternative technology induced higher antioxidant activity along with faster enrichment in wood derived phenolic compounds. In addition, the antioxidant activity, the total phenolic content and the low molecular weight phenolic compounds concentrations determined by HPLC exhibited significant positive correlations. The results also showed that alternative technology can be used as a valid method of ageing wine spirits since it allowed obtaining a high quality aged beverage through a more economically and environmentally sustainable process. A synergistic effect with the chestnut wood was also observed
N/A

The overall aims of this project were to assess the pharmaceutical quality and consistency of commercially available solid dose Sutherlandia frutescens containing products (viz. tablets & capsules) by exploring the use of monitoring the pharmaceutical presentation, flavonoid profile and antioxidant activity levels and to develop/or adapt methods and specifications that may be used for the quality control of such products.Stability tests were conducted on all of the selected SCP. The products were stored under elevated temperatures and environmental humidity conditions and total phenol, antioxidant and chromatographic analysis was conducted on these samples. Samples of each of the SCP were hydrolyzed using HCL and then analyzed using HPLC to test the stability of the flavonoids present in each product. The SCP investigated in this study physically appeared to be of quite good “pharmaceutical” quality, but generally lacked information on the date of manufacture and lacked package inserts, or when these were present they contained insufficient information.Based on the results obtained, it is recommended that, the manufacturers of SCP pay more attention to the information provided on the package inserts and the storage conditions for their products. Further the levels of antioxidant activity, total phenols and flavonoid (sutherlandins A to D) be used as specifications to control the quality of commercially available solid dose Sutherlandia frutescens containing preparations on an individual basis.

The ethanol extract of A. phylicoides was investigated for its antioxidant activity using the DPPH scavenging method. The extract showed good antioxidant results with a EC50 value of 10.64 ± 0.0842 µ/ml. The extract was also tested for antibacterial activity against microorganisms (Staphylococcus aureus, Enterococus faecalis, Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumonia) commonly known to pose a threat in the wellbeing of man. All tested microorganisms were significantly inhibited by the extract with the MIC values ranging from 3.13 µg/ml to 6.25 µg/ml. Folin-Ciocalteu’s reagent method was used to determine total phenolic content of dried and freshly prepared crude extract of A. phylicoides. Higher total phenolic content (28.28 ± 0.019 mg GAC/100g) and antioxidant activity (EC50, 10.64 ± 0.084 µg/ml) was observed in the dried extract compared to the fresh extract with a TPC value of 23.04 ± 0.003 mg GAC/100g and EC50 of 13.97 ± 0.066 µg/ml. Bioassay-guided fractionation of ethanolic extract from aerial parts of Athrixia phylicoides using silica and sephadex column chromatography led to the isolation of four known flavanoids, 5-hydroxy-6,7,8,3’,4’,5’-hexamethoxyflavon-3-ol (1), 3-0- demethyldigicitrin (2), 5,6,7,8,3’,4’-hexamethoxyflavone (3) and Quecertin (4). Due to the low yield, no further tests were done on compound 3. A DPPH-scavenging assay was performed to evaluate the antioxidant activity of the isolated compounds. All the tested compounds showed potent antioxidant activity with EC50 values ranging from 1.27 to 3.41 µg/ml. Compound 4 showed a higher antioxidant activity (EC50, 1.27 µg/ml) than vitamin C (EC50, 2.66 µg/ml) used as a control. The MIC values of the isolated compounds against tested microorganisms varied from 20 to more than 40 µg/ml. All the tested compounds showed no activity against S. aureus, B. pumilus, K. pneumonia and P. aeruginosa at the highest concentration tested (40 µg/ml). These compounds together with the extract were further analyzed by XTT assay on Vero cells. The extract showed a low toxicity effect on the cells at lower concentrations exhibiting EC50 value of 107.8 ± 0.129 µg/ml. Compound 4 showed minimal toxicity effect on the cells with a EC50 value of 81.38±0.331 µg/ml, compared to Compound 1 and 2 which exhibited EC50 values of 27.91 ± 0.181 µg/ml and 28.92 ± 0.118 µg/ml respectively. The results obtained from this study provide a clear rationale for the medicinal uses of Athrixia phylicoides.
Dissertation (MSc)--University of Pretoria, 2011.
Plant Science
unrestricted

The Fabaceae family is comprised of approximately 18 000 species in 650 genera, with wide geographic distribution. The species Glycyrrhiza glabra (licorice) and Periandra dulcis (licorice-of-the-earth) belong to the family Fabaceae. Licorice displays a variety of pharmacological activities, such as antiulcer, antiinflammatory, antioxidant, antimicrobial, among others. In ethnomedicine Brazilian, P. dulcis is used as a substitute/adulterant G. glabra. This study aimed to differentiate plants for antioxidant activity, the HPLC chromatographic profile and the antimicrobial activity. Plants roots were ground and macerated using as solvent ethanol: water (70:30, v/v). Became fractionation of crude extracts with organic solvents of increasing polarity (CH2Cl2, EtOAc, n-BuOH). The crude extract and the fractions were investigated for the content of total polyphenols, the antioxidant activity by DPPH and the inhibition of lipid peroxidation by TBARS method. The content of total phenolics ranged from 70.29 ± 2.98 to 85.78 ± 1.08 mg/g for P. dulcis and 137.7 ± 1.37 to 83.26 ± 2.71 mg/g to G. glabra. In the DPPH assay, the dichloromethane fraction was most effective in capturing free radicals in both plants. The butanol fraction of P. dulcis showed the greatest inhibition of TBARS, with IC50 of 1.38 ± 1.22 μg/mL and better chart the decay. In G. glabra, the dichloromethane fraction showed the best IC50 of 1.91 ± 0.73 μg/mL, but the best graphic decay was observed in the crude extract. Using the method proposed by the Brazilian Pharmacopoeia Fourth Edition, it was possible to differentiate the plants through the HPLC profiles. The absence of glycyrrhizin acid is evidence of falsification. However, the method does not allow the identification of the plant adulterant. The antimicrobial activity of the species was similar, varying only for Saccharomyces cerevisiae and Fusarium proliferatum. The sub-fractionation of P. dulcis improved activity against Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella pullorum.
A família Fabaceae é constituída por aproximadamente 18000 espécies em 650 gêneros, com ampla distribuição geográfica. As espécies Glycyrrhiza glabra (alcaçuz) e Periandra dulcis (alcaçuz-da-terra) pertencem à família Fabaceae. Alcaçuz exibe uma variedade de atividades farmacológicas, como antiúlcera, antiinflamatória, antioxidante, antimicrobiana, entre outras. Na etnomedicina brasileira, P. dulcis é utilizado como substituto/adulterante de G. glabra. O presente trabalho objetivou a diferenciação das plantas quanto à atividade antioxidante, o perfil cromatográfico por CLAE e à atividade antimicrobiana. As raízes das plantas foram moídas e maceradas utilizando como solvente etanol:água (70:30, v/v). Fez-se fracionamento dos extratos brutos com solventes orgânicos de polaridades crescentes (CH2Cl2, AcOEt, n-BuOH). O extrato bruto e as frações foram investigados quanto ao conteúdo de polifenóis totais, atividade antioxidante pelo método do DPPH e inibição da peroxidação lipídica pelo método do TBARS. O conteúdo de fenóis totais variou de 70,29 ± 2,98 a 85,78 ± 1,08 mg/g para P. dulcis e 137,7 ± 1,37 a 83,26 ± 2,71 mg/g para G. glabra. No ensaio do DPPH, a fração diclorometano foi mais eficiente na captação de radicais livres em ambas as plantas. A fração butanólica de P. dulcis demonstrou a maior inibição dos níveis de TBARS, com IC50 de 1,38 ± 1,22 μg/mL e melhor decaimento gráfico. Em G. glabra, a fração diclorometano demonstrou o melhor IC50 de 1,91 ± 0,73 μg/mL, mas o melhor decaimento gráfico foi observado no extrato bruto. Utilizando o método proposto pela IV Edição da Farmacopéia Brasileira, foi possível diferenciar as plantas através dos perfis cromatográficos obtidos por CLAE. A ausência do ácido glicirrizínico é indício de adulteração. Contudo, o método não permite a identificação da planta adulterante. A atividade antimicrobiana das espécies foi semelhante, variando apenas para Saccharomyces cerevisiae e Fusarium proliferatum. O sub-fracionamento de P. dulcis melhorou a atividade frente à Staphylococcus aureus, Pseudomonas aeruginosa e Salmonella pullorum.

Analytical chemistry has developed throughout time to meet current needs. At present, the interest in biorefinery is growing, due to environmental awareness and the depletion of fossil resources. Biomass from agricultural and forestry industries has proven to be excellent raw material for different processes. Biorefinering valuable species such as bioactive species from biomass, without compromising the primary process of the biomass is highly desirable. Pressurised fluid extraction (PFE) using water and ethanol as a solvent was developed for extracting betulin from birch (Betula pendula) bark. Apart from betulin, stilbene glucosides such as astringin, isorhapontin and picied were also extracted from spruce (Picea abies) using PFE. PFE is an advanced technique that extracts at temperatures above the solvent’s atmospheric boiling point. The applied pressure in PFE is mainly to maintain the liquid state of the extraction solvent. Parameters such as type of solvent, temperature, and time affect the extraction selectivity and efficiency. Therefore it is necessary to comprehend these parameters in order to optimise extraction. The DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to determine the antioxidant capacity and activity of the obtained bioactive species. The results showed high antioxidant capacity in bioactive species that were extracted at an elevated temperature, 180°C. Extraction and degradation occur simultaneously during the extraction. Hence, it is crucial to separate these two processes in order to obtain the actual value. An online hyphenated system of chromatographic separation electrochemical mass spectrometric detection was developed (LC-DAD-ECD-MS/MS). The electrochemical detector facilitates real-time monitoring of the antioxidant capacity and activity of each antioxidant and its oxidation products. This developed LC-DAD-ECD-MS/MS method enabled rapid screening of antioxidants and created a fingerprint map for their oxidation products. Characterisation and molecular elucidation of bioactive species were also performed. Degradation of bioactive species was investigated with the said online system and birch bark extract was compared with birch bark extracts that were hydrothermally treated. The obtained results showed some degradation of antioxidants at 180°C. In summary, the aim of this thesis was to develop analytical methods integrated with sustainable chemistry for extraction of bioactive species in biomass from the forestry industry. A novel online system using selective and sensitive detectors such as diode-array, electrochemical, and tandem mass spectrometry was developed to rapidly determine the antioxidant capacity and activity of antioxidants. Furthermore, tandem mass spectrometry enables identification of unknown bioactive species without the need of reference samples.
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 719

Oxidation limits the shelf life of many food products. Adding antioxidants to foods is the most common way to solve this problem. Reports on safety issues of synthetic food additives have raised consumer interest in "all natural" foods, without added antioxidants or with synthetic replaced with natural antioxidants. The natural antioxidants now in use are much more expensive and less potent than the synthetic antioxidants. Thus, effective and economical natural antioxidants are of great interest to researchers. Teng Cha is a type of herbal tea found in China that has reported high levels of antioxidants. Antioxidant activity of Teng Cha extract and its major component dihydromyricetin has been reported, but no studies have provided clear evidence for the antioxidant effectiveness of Tech Cha extracts. The goal of this study was to measure the antioxidant activity of Teng Cha extract and dihydromyricetin (DHM), a major component of Tech Cha extract. The DPPH assay was conducted and antioxidant activities of the crude extract and dihydromyricetin were evaluated in soybean oil based on the peroxide value, anisidine value, Totox value, headspace volatiles and headspace oxygen. Antioxidant effectiveness was also evaluated in a cooked beef model system. DHM was more potent than BHA in preventing soybean oil oxidation. The crude extract was not as effective as BHA and DHM, possibly because it contained transition metals. In cooked beef, DHM and the crude extract showed lower activity than BHA, possibly due to their low solubility. Overall, Teng Cha extract and DHM are potential natural food antioxidants for future applications.
Master of Science in Life Sciences

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas.
O género Adansonia digitata, comumente conhecido como baobab compreende oito espécies das quais seis são endémicas da ilha de Madagáscar (A. fony, A. za, A. madagascariensis, A. suarezensis e A. perrieri), uma de África (A. digitata) e uma da Austrália (A. gregorii). Entre as espécies supracitadas, a que tem merecido particular atenção é a A. digitata possivelmente devido à sua frequente utilização na medicina tradicional. O stresse oxidativo produzido no organismo relaciona-se com o aparecimento e/ou desenvolvimento de uma série de doenças crónicas não transmissíveis. Os compostos bioativos, presentes nos frutos, são capazes de neutralizar as estruturas radicalares formadas no metabolismo humano, diminuindo o risco do aparecimento de doenças crónicas, nomeadamente do foro cardiovascular e carcinogénico. As frutas são caracterizadas como fontes naturais de energia, hidratos de carbono, vitaminas e minerais, bem como, pelo seu contributo na aquisição de compostos bioativos que apresentam benefícios para a promoção da saúde em geral. A dietoterapia e a fitoterapia são duas vias terapêuticas de recurso natural em franca ascensão, relacionando o conceito de alimentos funcionais com a ação farmacológica uma vez que a ação antioxidante dos compostos bioativos depende, não só, das suas estruturas químicas como também das suas concentrações. Atualmente, o recurso e o interesse no conhecimento da composição nutricional e fitoquímica dos frutos exóticos têm aumentado, não só pelo fácil acesso a estes recursos naturais como pelo interesse económico que os mesmos podem potenciar a economia nacional dos países em desenvolvimento. O presente trabalho teve como objetivo a análise quantitativa dos compostos bioativos mais representativos da polpa do fruto da árvore Adansonia digitata, de Angola, cidade de Benguela, local de onde são provenientes os frutos estudados. Foi avaliada a atividade antioxidante pelo método espetrofotométrico do radical livre DPPH•. Os resultados obtidos mostram que o fruto do baobab angolano possui teores elevados de vitamina C e de fenólicos totais, o que explica a sua elevada capacidade antioxidante. Os teores de carotenóides apresentaram teores pouco significativos para a matriz estudada, uma vez que a coloração da polpa do fruto carece de pigmentação. Este estudo, embora preliminar, indicou por meio de uma abordagem fitoquímica in vitro, a presença de compostos com propriedades bioativas, visando o seu interesse para a sua aplicação numa vertente tanto alimentar como farmacêutica para a elaboração de suplementos naturais com atividade farmacológica e terapêutica. The Adansonia digitata genus, commonly known as baobab comprises eight species, which six are endemic from Madagascar island (A. fony, A. za, A. madagascariensis, A. suarezensis and A. perrieri), one of Africa (A. digitata ) and one from Australian (A. gregorii). Among the above species, the one who has received particular attention is the A. digitata, possibly due to its frequent use in traditional medicine. The oxidative stress produced in live organisms is related to the appearance and/or development of a series of non-transmissible chronic diseases. Phenolic compounds present in fruits are able to neutralize these substances, thus reducing the risk of development of free radicals associated to several pathologies, such as cardiovascular disease and cancer. Fruits are characterized as natural sources of energy, carbohydrates, vitamins and minerals as well as for their contribution in the contribution of bioactive compounds that exhibit high benefits for the health promotion. The dietotherapy and the phytotherapy are two therapeutic natural resources in great ascension, relating the concept of functional foods with the pharmacological action. The antioxidant activity of bioactive compounds depends, not only on their chemical structures as well as their concentrations in fruits. Currently, the knowledge and the interest in the nutritional and phytochemical composition of exotic fruits have been increasing, not only because of theirs easy access to the natural resources as the economic interest that they can boost the national economy of developing countries. The aimed of the present study was to evaluate the characterization of bioactive compounds more representative of the fruit pulp of Adansonia digitata tree, from Angola, more exactly from Benguela city place where fruits studied come from. Results showed that the Angolan baobab fruit has high levels of vitamin C and phenolic compounds, which explains its high antioxidant capacity. The carotenoids content were underrepresented in this studied, what was expected, once the fruit pulp lacks of pigmentation. This study, although considered as a preliminary and incomplete work indicated an in vitro phytochemical approach and the presence of compounds with bioactive properties, aiming the interest for its application, not only in the food diet as well as a natural resource for pharmaceutical industry, particularly in developing natural supplements with therapeutic and pharmacological activities.

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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)
Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG )
Nos ?ltimos anos, um n?mero crescente de pesquisas tem demonstrado o papel chave das esp?cies reativas (ERs) na acelera??o do processo de envelhecimento e agravamento de doen?as inflamat?rias e cr?nico-degenerativas. Tais esp?cies, altamente reativas, podem oxidar v?rias biomol?culas e provocar graves les?es no organismo. O efeito das ERs ? equilibrado no organismo por a??o de antioxidantes enzim?ticos e n?o enzim?ticos, sendo estes ?ltimos, representados em sua maioria pelos compostos fen?licos, sendo os flavon?ides os principais representantes. Os flavon?ides podem ser consumidos na dieta di?ria atrav?s de v?rios alimentos como frutas, legumes, vinhos etc., por?m, o principal alvo para busca de tais compostos s?o as plantas medicinais que s?o constantemente utilizadas pela popula??o. Tendo em vista a import?ncia de desenvolvimento e busca de novos compostos antioxidantes naturais, o presente estudo teve como principal objetivo avaliar a atividade antioxidante dos extratos etan?licos de algumas esp?cies vegetais que v?m sendo utilizadas na medicina popular, dentre outras finalidades, como antiinflamat?rias, cicatrizantes e outros usos relacionados a atividade antioxidante. As esp?cies vegetais utilizadas foram: Ageratum fastigiatum (GARDN.) R. M. KING et H. ROB., Croton antisyphiliticus MART., Kielmeyera rubriflora CAMB., Miconia ferruginata DC., e Norantea adamantium CAMB., coletadas no munic?pio de Diamantina ? MG e regi?es subjacentes, ?reas de predomin?ncia do bioma Cerrado. Avaliando a atividade antioxidante e teor de fen?licos totais (FT) nos extratos, pode-se observar que todos os extratos, exceto da A. fastigiatum (partes a?reas) apresentaram altos teores de compostos fen?licos, determinado pelo m?todo colorim?trico de Folin-Ciocalteau (FC) e eficiente poder redutor (PR), com destaque para a N. adamantium (partes a?reas), que apresentou o maior teor de FT (684,59 mg EAG/g extrato) e o menor valor para o PR (EC50 = 66,77 ?g/mL). Quanto ? captura das esp?cies radicalares DPPH? e ABTS?+, os extratos seguiram uma correla??o positiva, determinada pelo coeficiente de Pearson, ou seja, os extratos com maiores teores de FT tamb?m apresentaram as melhores atividades de captura das esp?cies radicalares com destaque para a N. adamantium (partes a?reas) e C. antisyphiliticus (caule) que apresentaram resultados de EC50 estatisticamente semelhantes ao padr?o ?cido g?lico (AG) para a captura de ambas as esp?cies radicalares utilizadas. Para a captura dos reagentes HOCl e H2O2 todos os extratos foram eficientes, por?m apresentaram melhores resultados apenas em altas concentra??es (>100?g/mL), sendo necess?rio um estudo de citotoxicidade para avaliar se tais concentra??es n?o s?o t?xicas ?s c?lulas humanas. Por fim, foi realizada uma avalia??o de interfer?ncia dos extratos no burst oxidativo produzidos por neutr?filos humanos isolados ativados com PMA e todos os extratos apresentaram atividade protetora frente ?s esp?cies produzidas pelo burst oxidativo com destaque para C. antisyphiliticus (caule) e A. fastigiatum (partes a?reas) que apresentaram menores valores de EC50, igual a 8,51 e 5,74 ?g/mL respectivamente.
Disserta??o (Mestrado) ? Programa de P?s-gradua??o em Ci?ncias Farmac?uticas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.
An increasing number of studies have been lately demonstrating the key role of the reactive species (RS) in accelerating aging and worsening inflammatory and chronic-degenerative diseases. This species, highly reactive, are able to oxidize several biomolecules and cause severe injuries to the organism. The effect of the RS is balanced by the enzymatic and non-enzymatic antioxidants, the latter being represented mostly by phenolic compounds and flavonoids key players which can be daily consumed in fruits, vegetables, wine etc. However, the main samples to search for these compounds are the medicinal plants extensively used by the population. Considering the importance of the development and screening of new natural antioxidant compounds, the present study aimed to evaluate the antioxidant activity of the ethanolic extracts of some species of plants that have been used in the popular medicine for its anti-inflammatory, healing and other uses related to antioxidant activity, among other features. The plants were: Ageratum fastigiatum (GARDN.); R. M. KING and H. ROB., Croton antisyphiliticus MART., Kielmeyera rubriflora CAMB., Miconia ferruginata DC., and Norantea adamantium CAMB., colleted at the municipality of Diamantina - MG and surroundings, where the biome Cerrado is predominant. The analysis of the antioxidant activity and the total phenolic content (TP) of the extracts showed that, except for the A. fastigiatum (aerial parts), all of the others presented high contents of phenolic compounds through the colorimetric assay of Folin-Ciocalteau (FC) and the effectiveness of the reductive power (RP). Highlights here to N. adamantium (aerial parts) extract which demonstrated the highest content of TP (684,59 mg EAG/g extract) and the lowest value of RP (EC50 = 66,77 ?g/mL). Regarding the capture of the following free radicals, DPPH? and ABTS?+, the extracts demonstrated a positive correlation, determined by the Pearson factor, which means that the extracts with the highest contents of TP also displayed better capture activities of those free radicals. It is important to emphasize N. adamantium (aerial parts) and C. antisyphiliticus (stem), once they presented statistically similar EC50 to the garlic acid (GA) for the capture of both of the free radicals used. For the capture of HOCl and H2O2, all the extracts showed to be efficient, nevertheless they presented better results only in high concentrations (>100?g/mL). Therefore it is relevant to perform a citotoxicity assay on human cells. At last, the interference of the extracts was evaluated on the oxidative burst produced by human neutrophils isolated and activated with PMA and all of them showed to be protective against the free radicals produced in the assay, in which C. antisyphiliticus (stem) and A. fastigiatum (aerial parts) standout for the lowest EC50, 8,51 and 5,74 ?g/mL respectively.

SCREENING FOR ANTIOXIDANT ACTIVITIES OF SEVERAL MEDICINAL PLANT EXTRACTS AND THEIR EFFECTS ON GLUTATHIONE-S-TRANSFERASE ACTIVITY ABSTRACT Sagdiç
oglu Celep, A. Gü
lç
in Ph.D., Department of Biochemistry Supervisor: Assoc. Prof. Nursen Ç
oruh May 2005, 154 pages The consumption of fresh fruits, vegetables, and medicinal plants are known to be associated with a long life span and low incidence of oxidative stress related diseases such as Alzheimer&
#8217
s, Parkinson&
#8217
s, cancer, aging and cardiovascular diseases. Fitotherapeutic effects of medicinal plants is virtually attributable to their phenolic compounds with low cytotoxicity. In this study, plants used in Anatolian folk medicine for their effects such as antiinflammatory, antiulcer, antipyretic, fertility, analgesic and aphrodisiac, namely Aesculus hippocastanum L., Papaver bracteatum L., Urtica urens L., Gundelia tournefortii L., Prangos ferulacea L., Chaerophyllum macropodum Boiss., Heracleum persicum Desf., Allium vineale L., Aconitum cochleare Woroschin, Rheum ribes L., Ferula rigidula DC., Rosa heckeliana Tratt, were screened for their antioxidative effects. Antioxidant characteristics of the specified plants were studied using lipid peroxidation inhibiton and DPPH radical scavenging methods. Total phenolics content and their effects on glutathione-S-transferase activity of the plants were further investigated. Rheum ribes L, Ferula rigidula DC, Rosa heckeliana Tratt., Prangos ferulacea L. were found to be very effective antioxidants and also effective inhibitors for glutathione-S-transferase activities among the plants. Rosa heckeliana Tratt. root extracts exhibited very high total phenolics content (0.7 mg/mg of extract) and antioxidant activity with IC50 values of 11.2 µ
g/mL and 5.1 µ
g/mL for DPPH scavenging and lipid peroxidation inhibition, respectively. Ferula rigidula DC was identified as the most potent inhibitor for glutathione-S-transferase activity, with IC50 values of 49 µ
g/mL.

Presented diploma thesis is dedicated to the determination of selected chemical parameters of fruits of new currant varieties. The theoretical part is focused on the characteristics of currant, the biologically active substances of its fruits and also the utilization of current in the food industry. Further part of the theory deals with the main chemical parameters which were examined: polyphenols, anthocyanins, ascorbic acid and antioxidant activity. In the practical part there were determined selected chemical parameters in six white, twelve red and thirteen black varieties of currant. Anthocyanins and polyphenols have been determined spectrophotometrically. The content of ascorbic acid in selected varieties of currant was determined by HPLC. As a technique for the determinationof the antioxidant activity was selected the method of free radical DPPH.

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This study investigated the antioxidant activity using biosensors based on carbon paste electrode (CPE) modified with crude extract of laccase (Pycnoporus sanguineus, activity 2019 U L-1) in different compositions. The biosensor consists of carbon nanotubes activated with DNA (CPEL-DNA: CN) showed the best sensitivity level, 0.0549 μA / μM and 1.2 uM detection limit (LOD) in the concentration range of 20-140 μM of rutin. This biosensor showed excellent stability over 10 days and reproducibility (RSD <5%). This biosensor was used to determine the total amount of phenol in coffee samples (expressed by the equivalent rutin) using electroanalytical technique. For the evaluation of its detection capability, the results were compared with other electroanalytical techniques using analytical basis as samples of commercial coffee from different countries. The CPL-DNA: CN was used to determine the total amount of phenol in coffee samples (expressed by the equivalent rutin). Thus, it was possible to propose the CPL as an analytical tool for the detection of phenols. In this research, we developed several studies using different CPE to investigate the antioxidant natural product profile such as coffee samples, dry extracts of acerola, obtained by cyclic voltammetry (CV),) differential pulse voltammetry (DPV) and square wave voltammetry (SWV), which allowed to conclude classes of antioxidants present in the samples. The quantitative determination of these compounds was performed using the standard addition method by differential pulse voltammetry and electrochemical index (EI) has been proposed for estimating the oxidizing potential between different samples. Carbon paste electrode was also investigated using the different quality control samples commercialized produced from acerola employing DPV for the quantification of ascorbic acid (AA) in all samples, where the limit of detection (LOD) and limit of quantification (LOQ) was 0.31 and 0.96 μM and with excellent recovery between 97.4 to 102.2% The DPPH tests were used to compare the antioxidant activity in coffee and acerola samples. The Folin-Ciocalteu method was used to estimate the antioxidant activity of rutin from coffee samples. These methods proposed had advantages such as simplicity of sample preparation and the speed of the analysis of antioxidant capacity.
Neste trabalho foram realizados ensaios de atividade antioxidante em amostras de acerola, café, bem como de outros extratos secos de frutos vermelhos, empregando-se eletrodos convencionais de pasta de carbono (EPC), bem como biossensores de EPC modificados com extrato bruto de lacase (EPCL), partindo de Pycnoporus sanguineus (atividade 2019 U L-1) em diferentes composições com e sem uso de agentes modificadores, visando avaliar melhor sistema. Para além consolidar o uso de métodos eletroanalíticos, i.e. voltametria cíclica (VC), voltametria de onda quadrada (VOQ) e pulso diferencial (VDP), na análise de produtos naturais, seja para avaliar perfil antioxidante, seja para inferir sobre classes de antioxidantes presentes nas amostras, pode-se neste estudo avaliar o papel de diferentes agentes modificadores. O biossensor constituído de nanotubos de carbono ativado com DNA (EPCL-DNA) apresentou o melhor nível de sensibilidade 0,0549 μA/μM e um limite de detecção (LOD) de 1,2 μM no intervalo de concentração de 20-140 μM de rutina. Além disso, o biossensor mostrou ter uma excelente estabilidade ao longo de 10 dias e reprodutibilidade (RSD < 5%). Para a avaliação da sua capacidade de detecção, os resultados obtidos foram comparados com outras técnicas eletroanalíticas usando como base analítica amostras do café comercial de diferentes países. O EPCL-DNA foi empregado para determinar a quantidade de fenol total nas amostras de café (expressa pelo equivalente de rutina). Com isso, foi possível propor os EPCL como ferramenta analítica para a detecção dos fenóis. A determinação quantitativa desses compostos foi realizada através da construção de curvas de calibração para VPD e o índice eletroquímico foi proposto para estimar o potencial antioxidante entre diferentes amostras. Também foi investigado o uso de EPC para o controle de qualidade de diferentes produtos obtidos a partir da acerola, empregando VPD para a quantificação de ácido ascórbico (AA) em todas as amostras, onde os limites de detecção (LD) e o Limite de quantificação (LQ) foi de 0,31 e 0,96 μM respectivamente e com uma excelente taxa de recuperação entre 97,4-102,2%. Os ensaios de DPPH foram utilizados para comparar a atividade antioxidante nas amostras de café e acerola. O método de Folin-Ciocalteu foi usado para estimar a atividade antioxidante da rutina nas amostras de café. Pode concluir-se que os métodos propostos apresentaram vantagens, como a simplicidade na preparação das amostras e a rapidez do ensaio da capacidade antioxidante.

Ce travail rapporte le lien entre l'activité larvicide et la composition chimique des différents extraits des pieds mâles et femelles de Mercurialis annua L. une Euphorbiaceae souvent utilisées dans la médecine traditionnelle. Le matériel végétal exploité dans notre étude est ramassé dans quatre régions de la Tunisie situées dans des étages bioclimatiques différents : Bizerte, Jandouba, Nabeul et Beja. Cette étude comprend une première partie consacrée à une synthèse bibliographique. La deuxième partie est consacrée aux expérimentations et résultats. En effet, nous avons évalué l’activité antioxydante des différents extraits à l'aide d'essais DPPH. Les composés phénoliques ont été identifiés et quantifiés par chromatographie liquide couplée à un détecteur UV et à la spectrométrie de masse (LC-UV-ESI / MS). Nos résultats ont montré que les extraits méthanoliques des plantes mâles ont une activité antioxydante (AOA) plus élevé que celle détectée dans les extraits des plantes femelles. D’autre part, les extraits de plantes mâles et femelles de Bizerte ont affiché le taux d'AOA le plus élevé. Pour les deux sexes, les extraits de plantes de Beja ont la plus faible AOA. Certains composés phénoliques tels que : la narcissine, la gallocatéchine, la rutine, l'épigallocatéchine et l'épicatéchine ont été identifiés et quantifiés par LC-MS. D’autre part, l'activité larvicide des différents extraits aqueux de Mercurialis annua L. contre les larves de Tribolium confusum (Du Val) ont montré que la mortalité pouvait atteindre 100% après 48 heures d'exposition pour certains extraits, ceci est confirmé par leur faible LC50. Par ailleurs, l’étude de l’activité anti-acétylcholinestérase des extraits testés montrent que ces derniers sont des inhibiteurs de l’AChE plus puissants que la galantamine utilisée comme contrôle positif. Notre étude a confirmé que des extraits des feuilles et des graines des deux sexes de Mercurialis annua L., provenant des différentes régions de la Tunisie, peuvent donc être exploités pour d’autres activités biologiques, parmi lesquelles l’action inhibitrice de l’AChE En effet ces extraits sont riches en composés phénoliques, ce qui leur confère cette propriété thérapeutique contre la maladie d'Alzheimer et le piégeage les radicaux libres
This work reports the link between the larvicidal activity and the chemical composition of the different extracts of the male and female feet of Mercurialis annua L. a Euphorbiaceae often used in traditional medicine. The plant material used in our study is collected in four regions of Tunisia located in different bioclimatic stages: Bizerte, Jandouba, Nabeul and Beja. This study includes a first part devoted to a bibliographic synthesis. The second part is devoted to experiments and results. Indeed, we evaluated the antioxidant activity of the different extracts using DPPH tests. The phenolic compounds were identified and quantified by liquid chromatography coupled with a UV detector and mass spectrometry (LC-UV-ESI / MS). Our results showed that methanolic extracts from male plants have higher antioxidant activity (AOA) than that detected in extracts from female plants. On the other hand, male and female plant extracts from Bizerte showed the highest AOA level. For both sexes, Beja plant extracts have the lowest AOA. Certain phenolic compounds such as: narcissin, gallocatechin, rutin, epigallocatechin and epicatechin have been identified and quantified by LC-MS. On the other hand, the larvicidal activity of the various aqueous extracts of Mercurialis annua L. against the larvae of Tribolium confusum (Du Val) showed that the mortality could reach 100% after 48 hours of exposure for certain extracts, this is confirmed. by their low LC50. Furthermore, the study of the anti-acetylcholinesterase activity of the extracts tested shows that they are more potent AChE inhibitors than galantamine used as a positive control.Our study confirmed that extracts of the leaves and seeds of both sexes of Mercurialis annua L., coming from different regions of Tunisia, can therefore be exploited for other biological activities, among which the inhibitory action of AChE. Indeed, these extracts are rich in phenolic compounds, which gives them this therapeutic property against Alzheimer's disease and scavenging free radicals

Ekstrakcijom heksanom, a zatim 80% etanolom predhodno pripremljenog tropa odIZ odabranih genotipova Bačka, Knjaz, Novosadski niski, O₂, Rutgers i Saint Pierreparadajza, dobijeni su heksanski i etanolni ekstrakti tropa. Sadržaj karotenoida uheksanskim i polifenolnih jedinjenja, flavonoida i askorbinske kiseline u etanolnimekstraktima određen je spektrofotometrijskim metodama. Identifikacija ikvantifikacija pojedinih karotenoida u heksanskim i polifenolnih jedinjenja uetanolnim ekstraktima tropa paradajza izvedena je HPLC analizom. U ostacimanakon ekstrakcija tropa paradajza određen je sadržaj prehrambenih vlakana.Spektrofotometrijskim testovima određena je antiradikalska aktivnost na DPPHradikale i redukciona sposobnost dobijenih ekstrakata. ESR spektroskopijomispitan je uticaj etanolnih ekstrakata na reaktivne hidroksil i superoksid anjonradikale. Pored toga, ispitana je i helirajuća sposobnost etanolnih ekstrakata.Antiradikalsko delovanje na DPPH radikale ostataka nakon ekstrakcija tropaparadajza radikale, takođe je utvrđeno. Ispitana je in vitro antiproliferativnaaktivnost frakcija ekstrakata, njihovim delovanjem na rast tri histološki različitehumane ćelijske linije: MCF-7 (adenokarcinom dojke), HeLa (epitelni karcinomcerviksa) i MRC-5 (fetalni fibroblastni karcinom pluća). Rezultati ispitivanjahemijskog sastava, antioksidativne i antiproliferativne aktivnosti ekstrakata, kao iostataka nakon ekstracija tropa odabranih genotipova paradajza ukazuju namogućnost iskorišćenja ovog sporednog proizvoda kao potencijalnog izvoraprirodnih antioksidanata, koji bi našli primenu u prehrambenoj, farmaceutskoj ikozmetičkoj industriji.
Tomato pomaces obtained from selected tomato genotypes (Bačka, Knjaz, Novosadski niski,O2, Rutgers and Saint Pierre) were extracted sequentially with hexane and 80% ethanol. Thecontent of carotenoids i hexane and total polyphenolics, flavonoids and ascorbic acid inethanolic extracts was determined by spectrophotometric methods. Identification andquantification of individual carotenoids in hexane and polyphenolics in ethanolic extractswas determined by HPLC analysis. The content of dietary fiber was determined in theresidues after extraction of tomato pomaces. The scavenging activity on DPPH radicals andreducing power of the obtained extracts were determined spectrophotometrically. Theinfluence of ethanolic extracts on reactive hydroxyl and superoxide anion radicals wasexamined by electron spin resonance (ESR) spectroscopy. In addition, the chelating ability ofethanolic extracts was investigated. Scavenging effect on DPPH radicals of the residue afterextraction of tomato pomace, has also been established. Antiproliferative activity ofinvestigated extracts was determined in vitro, testing their influence on the growth of threehistologically different human cell lines: MCF-7 (breast adenocarcinoma), HeLa (cervixepithelioid carcinoma) and MRC-5 (fetal lung). Based on the results of chemical analysis,significant antioxidant and antiproliferative activity of the tomato waste extracts, as well asresidues after extraction showed that tomato waste obtained from different tomato genotypesshould be regarded as potential source of natural antioxidants, which can be used for variouspurposes in the food, pharmaceutical and cosmetic industry.

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O amendoim A. hypogaea L. é a quarta oleaginosa mais consumida no mundo e suas sementes são altamente energéticas, com grandes quantidades de lipídios, proteínas, vitaminas e carboidratos. Diversas atividades farmacológicas já foram observadas em extratos de raízes, folhas e sementes, sendo a principal delas a atividade antioxidante. Neste trabalho, foi realizada a comparação entre duas metodologias (por maceração e assistida por micro-ondas) para a extração de compostos antioxidantes, incluindo o resveratrol. Também foi realizada a comparação entre extratos de diferentes órgãos de cultivares brasileiras (IAC 886, IAC Caiapó, IAC Tatu ST, IAC 8112 e IAC 99-1) quanto à atividade antioxidante, por DPPH, ao teor de compostos fenólicos, por Folin-Ciocalteu, e ao teor de resveratrol, por HPLC. Por fim, foram estabelecidos protocolos de cultura de tecidos para explantes de sementes, visando à produção de calos e plantas in vitro para posterior dosagem de compostos de interesse, tendo em vista a possibilidade de modulação das condições in vitro. As melhores condições determinadas para a extração por maceração de antioxidantes de A. hypogaea foram 80% de etanol em água como solvente, trituração com almofariz e pistilo, 50 mL solvente por grama de material vegetal seco, 120 minutos de incubação e dois estágios de extração. As melhores condições para a extração de resveratrol assistida por micro-ondas foram o uso de 37 mL de solvente/g material vegetal seco, com agitação de 1200 rpm por 15 minutos, a 37C. De uma maneira geral, os extratos de raízes e oriundos de micro-ondas apresentaram maior atividade antioxidante (até 92,36 2,71%), teor de compostos fenólicos (até 54,15 1,39 mg EAG/g extrato) e teor de resveratrol (até 1,614 0,356 mg/g extrato). Dentre as cultivares estudadas, IAC Tatu e IAC 99-1 foram as que apresentaram os teores mais elevados. Brotos e calos friáveis foram obtidos a partir de cotilédones, eixos embrionários e folíolos embrionários cultivados em meios suplementados com BAP e picloram, respectivamente.
Peanut A. hypogaea L. is the fourth most consumed oleaginous in the world and its seeds are high energetic, with high amounts of lipides, proteins, vitamins and carbohidrates. Several pharmacological activities have been observed in extracts of roots, leaves and seeds, especially an antioxidant activity. In this work, the comparison between two extraction methodologies (by maceration and microwave assisted extraction) for the extraction of antioxidant compounds, including resveratrol, was studied. We also carried out a comparison between extracts from different organs of Brazilian cultivars (IAC 886, IAC Caiapó, Tatu ST IAC, IAC 8112 and IAC 99-1) for antioxidant activity by DPPH, the content of phenolic compounds by Folin-Ciocalteu and the resveratrol content by HPLC. Finally, we established tissue culture protocols for seed explants, aiming at the production of in vitro plant material for future measurement of compounds of interest in the view of possible modulation of in vitro conditions. The best conditions for the extraction of antioxidant from A. hypogaea compounds by maceration were 80% of ethanol in water as a solvent, trituration by mortar and pestle, 50 mL solvent/g dry plant, 120 minutes of incubation and two stages of extraction. The best conditions for the extraction of resveratrol assisted by micro-wave were the use of 37 mL of solvent for each gram of dry plant, with 1200 rpm of agitation for 15 minutes, with 37oC. In general, root extracts and assisted by microwave showed higher antioxidant activity (until 92,36 2,71%), phenolic (untill 54,15 1,39 mg AGE/g extract) and resveratrol content (untill 1,614 0,356 mg/g extract). Among the studied cultivars, IAC Tatu and IAC 99-1 showed the best results. In tissue culture, shoots and friable calli were obtained from cotiledons, embryonic axis and embryonic leaflet cultured in media supplemented with BAP and picloram, respectively.

Flavonoids were identified and quantified in samples of dry leaves of plant Stevia rebaudiana Bertoni. Content of flavonols (kaempherol, quercetin, myricetin, rutin) and flavons (apigenin, luteolin) were compared in three samples (standard leaves of Stevia rebaudiana Bertoni, Stevia rebaudiana Bertoni origin from Ukraine and from Czech republic), that were extracted by three extraction methods (PSE, ultrasonic extraction, Soxhlet extraction) with two polar solvents, methanol and ethanol, in combination with non-polar hexane. Extracts were analyzed by HPLC with detection UV-VIS. Antioxidant activity and total content of flavonoids in extracts were measured by spectrometry. Stable free radical DPPH. was used for determination of scavenging effect in extracts. PSE was the most effective extraction method with this conditions – 120 °C, dynamic mode and with methanol like solvent.

U ovom radu je izvršeno kvantitativno određivanje i identifikacija biljnih fenola i flavonoida etanolih ekstrakata ploda peršuna (Petroselini fructus), kore krušine (Frangulae cortex), lista pitome nane (Mentha piperitae folium), ploda kima (Carvi fructus) i lista breze (Betulae folium), kao i komercijalnog preparata Vitalplant^® ((Frangulae cortex(35 %),  Mentha piperitae folium(20%),  Carvi fructus(20 %), Petroselini fructus (25 %)). U nastavku istraživanja ispitivana je antioksidantna aktivnosti etanolih ekstrakata primenom direktnih, ESR “spin trap“ spektroskopskih metoda određivanja “skevindžer“ aktivnosti na superoksid anjon i  hidroksil radikale i indirektnih, spektrofotometrijskih testova za određivanje skevindžer“ aktivnosti na DPPH˙ radikale, redoks potencijala i helatacione aktivnosti, kao i antioksidantne aktivnosti u sistemu  β-karoten-linolna kiselina. Osim navedenog, deo istraživanja je posvećen ispitivanju termičke stabilnosti ekstrakata navedenih biljaka i komercijalnog preparata Vitalplant^® radi sticanja uvida u mogućnost njihove primene u  pekarskim proizvodima. U poslednjoj fazi rada, izvršeno je određivanje sposobnosti pulvisa i etanolnog ekstrakta komercijalnog  preparata Vitalplant^® da inhibiraju oksidaciju lipida u keksu, primenom spektrofotometrijskih testova “skevindžer“ aktivnosti  na DPPH˙ radikale i MDA testa. Ispitane biljne sirovine, kao i komercijalni preparat Vitalplant^® su bogat izvor jedinjenja iz klase biljnih fenola. Sve ispitane biljne droge poseduju antioksidantnu aktivnost, koja se značajno ne menja usled termičkog tretmana. Dodatak biljne mešavine Vitalplant^® , upravo proporcionalno njenom sadržaju,  dovodi do povećanja antioksidantne aktivnosti keksa i smanjenja stepena lipidne peroksidacije. 
In this paper, quantitative determination and identification of plant phenolics and flavonoids of ethanolic extracts obtained from parsley fruit (Petroselini fructus), buckthorn bark (Frangulae cortex), mint leaves (Mentha piperitae folium), caraway fruit  (Carvi fructus), birch leaves (Betulae folium), as well as from commercial preparation Vitalplant® ((Frangulae cortex(35 %), Mentha piperitae folium (20%), Carvi fructus(20 %), Petroselini fructus (25 %)) was performed. In addition, antioxidant  activity of ethanolic extracts was tested, by applying direct, ESR “spin trap“  spectroscopic methods for the determination of scavenging activity on superoxide anion and hydroxyl radicals, and indirect, spectrophotometric methods for the determination of DPPH˙ radical scavenging activity, reducing power, chelating activity and antioxidant activity in  β-carotene-linoleic acid model system. Moreover, thermal stability of the ethanolic extracts was tested in order to get insight into possible application of the extracts in bakery products. Finally, the ability of the commercial preparation Vitalplant®, in the form of powder and extract, to inhibit oxidative changes of cookies was tested by applying spectrophotometric DPPH radical scavenging and MDA tests.According to obtained results, investigated plant samples, including commercial preparation Vitalplant®, are rich source of plant phenolics. Investigated plant drugs possess antioxidant activity, which is not significantly changed after the thermal treatment. Cookie supplementation with commercial preparation Vitalplant® results in  better oxidative stability of lipids and enhanced antioxidant activity of the cookies.

Ispitivanja hemijskog sastava etarskih ulja iekstrakata izvedena su na vrsti Myrtus communisL. sa pet lokaliteta iz Crne Gore. Pored toga,ispitana je njihova antioksidantna aktivnost urazlicitim in vitro sistemima kako bi se utvrdiouticaj pomenutih ekstrakata i etarskih ulja naneutralizaciju DPPH, NO, OH i 2- radikala, kaoi njihov uticaj na lipidnu peroksidaciju ulipozomima i inhibiciju enzima ksantin-oksidaze.Takode, ispitana je i antibakterijska aktivnostetarskih ulja i ekstrakata ove vrste na 9bakterijskih sojeva, kao i njihov antimutagenipotencijal na bakterijskom soju Escherichia coliIC 202.
In this tessis the chemical analysis of the essential oils and methanolic extracts from five plant samples of Myrtus communis L., collected from different localities in Montenegro, have been investigate. Beside that, their antioxidant activity in differwnt in vitro systems has been study to establish their scavenging potential towards DPPH, NO, OH, and O2- free radicals, as wel as their effects on lipid peroxidation in liposoma and inhibition enzyme XOD. Also, the antibacterial activity of the essential oils and methanolic extract has been study on 9 bacterial strains, as wel as their antimutagenic effects on bacterial strain E. Colli IC202.

Cyclolinopeptides (CLs) are hydrophobic cyclic peptides found in flaxseed. They show immunosuppressive activity, but the biological function of these compounds is largely unknown. This thesis presents the results of studies that were conducted to determine whether CLs could act as antioxidants. In the first study, flaxseed oil was passed over a silica adsorbent column to remove polar compounds. The polar compounds were then eluted from the silica absorbant using a series of increasingly polar solvents. Individual polar fractions were then added back to the silica-treated flaxseed oil and the oxidative stability index of these samples was determined at 100 °C. A polar fraction containing mainly CLA, β/γ- and δ-tocopherol increased the induction time of silica-treated flaxseed oil from 2.3 ± 0.28 h to 3.2 ± 0.41 h. A positive effect of the polar fraction containing a mixture of CLA and CLD-CLG on the oxidative stability of oil was also observed. The antioxidant mechanism of CLs was investigated in several model systems using electron spin resonance spectroscopy. The concentration of radicals in a DMPO (5,5-dimethyl-1-pyrroline-N-oxide) radical-CLs reaction mixture was monitored. All CLs exhibited dose dependent scavenging activities. CLA–CLC reactions with DMPO-OH at a concentration of 5 mM resulted in a 24–30% decrease in electron paramagnetic resonance (EPR) signal intensity. The reaction of CLs and the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) revealed a more complex interaction than simple radical scavenging. Peptides (CLG and CLG") that contained both tryptophan and methionine showed stronger radical scavenging activity than did CLs containing methionine or methionine sulfoxide but not tryptophan (CLB and CLC). Irradiation of the reaction mixture of DPPH• and peptide with UV light also affected the radical scavenging behaviour. Scavenging activities of DPPH• by CLB, CLC and CLA were enhanced by light, whereas scavenging of DPPH• by the tryptophan containing peptides CLG and CLG″ was not affected. High-performance liquid chromatography with mass spectrometry (HPLC-MS) analysis of the reaction mixtures after a radical scavenging reaction was used to determine the impact of radical scavenging on the peptides. These reactions revealed new masses that were identified and characterized. It was established that DPPH• reacted with the methionine of CLB and with tryptophan in CLG and CLG, by formation of a new covalently-bonded species. Covalent linkages between these amino acids (alone or in peptides) and DPPH• have not been reported previously.

The addition of pea fibre to wheat bread supports the growing trend of improving health through diet. Various evaluation tools (bread scoring, C-cell, texture profile analysis, and ultrasound) were used to monitor the sensory and mechanical quality of air bubbles in bread. Different pea fibre particle sizes (250, 125, 180, 90 μm) were added at 0, 2, 4, 6, 8 g/serving into a bread formulation. Improvements in specific loaf volume were observed when water absorption was optimized. Adequate water absorption mitigated the high dough viscosity effect of pea fibre. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay was used to measure antioxidant activity of pea fibre. All particle sizes of pea fibres had substantially greater antioxidant scavenging ability compared to wheat flour. The DPPH scavenging activity of pea fibre approached that of ascorbic acid by the end of the assay. Fibre-enriched bread had higher antioxidant activity compared to that of the control bread.

8. Abstract The fruit of the European elder, Sambucus nigra L., is used in therapy as a drug Sambuci fructus for its diaphoretic, diuretic and laxative effects. Cultivars of European elder are being studied for the use in the food industry and pharmacy. The fruit contains especially large amount of anthocyanins and flavonoids that are known for their antioxidant activity. The aim of this work is to measure the antioxidant activity of the drug Sambuci fructus and of the fruit of the European elder cultivars Samdal, Mammut, Sambo, Sambu, Sampo, Bohatka, Haschberg, Weihenstephan, Allesö, and Samyl. An extract containing anthocyanins was obtained from fruit by a process based on extraction of frozen material with acidified water at high temperature, followed by separation with polymer non-ionogenic polystyrene-divinylbenzene sorbent. The content of anthocyanins in the extracts was determined spectrophotometrically using a modified pH-differential method. The absorbance was measured along the range of 350 - 600 nm. The content of the anthocyanins was quantified in units of mg of cyanidin 3-glucoside in 1 ml of extract. The content ranged from 0.33 - 2.76 mg cyanidin 3-glucoside/ml of extract. The highest content was in the extract from the fruit of the cultivar Samdal and the lowest was of the cultivar Mammut....

Phytochemicals found in grains complement those found in fruits and vegetables. These phytochemicals, though minor compounds, contribute to the antioxidant properties which are related to the health benefits associated with the consumption of whole grain. In this thesis project, nine barley genotypes of diverse origin namely CI2230 from Nepal, CI1248 from Israel, 3 Peruvian genotypes; Peru 3, Peru 16 and Peru 35, Hokuto Hadaka from Japan, EX116; a cross between Moroccan and Canadian genotype, EX83; a cross between two Canadian genotypes and EX127; a cross between Canadian and German genotypes were studied. The genotypes were categorized based on appearance into purple, black and yellow grains. Phenolic acids and flavonoids were identified and quantified in these diverse genotypes using HPLC-ESI-MS analysis. The main classes of dietary flavonoids studied in the barleys were anthocyanins and flavan-3-ols. Phenolic acids were identified and quantified (p-coumaric, ferulic, sinapic, caffeic, vanillic). Three ferulic acid dehydrodimers (8-0-4’ DFA, 8-5’ benzofuran form and 5-5’ DFA) were also identified. The most abundant dimeric flavan-3-ols were procyanidins B3 and prodelphinidin B3. The monomeric unit, (+)-catechin, was the most abundant while catechin glucoside (m/z 451) was also identified. Among the Peruvian genotypes, Peru 16 and Peru 35 exhibited relatively high levels of total PA content. Total phenolic content and antioxidant activities of methanolic, acetone and alkali hydrolyzed extracts of the nine barley genotypes was determined by the Folin- Ciocalteau assay, DPPH radical scavenging assay and oxygen radical absorbance capacity (ORAC assay).The acetone extract exhibited the highest antioxidant capacity using all the methods of analysis. Furthermore, dark colored grains were found to exhibit higher contents of phenolic compounds. The phenolic acids, PAs and anthocyanins identified and quantified had significant contribution to the overall antioxidant capacity of the barley whole grain. Four hull-less genotypes namely CI2230, EX127, CI1248 and Peru 35 were further partially sprouted to establish the effects of sprouting on phenolic acid composition. Partial sprouting was observed to significantly increase the soluble conjugated phenolic acids. The barley genotypes studied were found to contain different quantities of phytochemicals and had high proanthocyanidin content thereby rendering them as alternative sources of antioxidants. Barley sprouts present a possible novel food ingredient with improved properties such as phenolic acid composition and other benefits such as easier incorporation into food products under development.

Вещества, обладающие антирадикальной активностью (АРА) играют ведущую роль в системе защиты организма от свободных радикалов. Общие недостатки известных способов оценки АРА выражаются в том, что измерения проводятся непрямыми методами, что затрудняет количественно оценивать содержание веществ с антирадикальными свойствами. Результаты измерений представляются в относительных единицах, в качестве эталонных веществ чаще всего используются: тролокс, галловая и аскорбиновая кислоты, проявляющие разную АРА, что не позволяет сравнивать результаты между собой. Таким образом, существует необходимость в разработке прямого, безэталонного метода оценки антирадикальной активности. Одним из потенциально возможных решений данной проблемы является метод ЭПР-спектроскопии на модели 2,2-дифенил-1-пикрилгидразил. Цель и задачи исследования. Исследование безэталонным методом оценки антирадикальной активности природных и синтетических антиоксидантов на модели 2,2-дифенил-1-пикрилгидразил с использованием ЭПР-спектроскопии. Отработка методики определения антирадикальной активности на модели ДФПГ методом ЭПР-спектроскопии. Получение и анализ значений антирадикальной активности для ряда веществ с антирадикальными свойствами. Сравнение с результатами полученными методом потенциометрического определения антиоксидантной активности с использованием медиаторной системы. Полученные результаты. Установлены оптимальные условия для проведения анализа. Проведено исследование - новым, безэталонным методом оценки антирадикальной активности, ряда природных и синтетических антиоксидантов. Установлены значения антирадикальной активности ряда природных и синтетических антиоксидантов. Рассмотрены различные варианты механизмов ингибирования свободных радикалов и их зависимость от структуры антиоксиданта.
Substances with anti-radical activity (ARA) play a leading role in the body's defense system against free radicals. General disadvantages of the known methods of evaluating the APA expressed in the fact that measurements are carried out by indirect methods, making it difficult to quantify the content of substances with antiradical properties. The measurement results are presented in relative units, as reference substances are most often used: Trolox, ascorbic and gallic acid, exhibit different ARA, which does not allow to compare the results with each other. Thus, there is a need to develop direct, reference-free method of evaluating anti-radical activity. One possible solution to this potential problem is the method of EPR model 2,2-diphenyl-1-picrylhydrazyl. The purpose and objectives of the study. Study standardless method for assessing the antiradical activity of natural and synthetic antioxidants model 2,2-diphenyl-1-picrylhydrazyl using EPR spectroscopy. Testing methods for determining the anti-radical activity in the DPPH model EPR spectroscopy. Obtaining and analyzing anti-radical activity values for a number of substances with antiradical properties. Comparison with the results obtained by potentiometric determination of antioxidant activity using a mediator system Results. The optimum conditions for analysis. The research - the new reference-free method of evaluating anti-radical activity, a number of natural and synthetic antioxidants. Established values antiradical activity of natural and synthetic antioxidants. Various embodiments of the mechanisms of inhibition of free radicals and their antioxidant dependency structure.

This thesis contains six chapters and the research presented within focuses on three parts. The first part (chapter one to three) was the isolation of antibacterial and antioxidant mushroom metabolites, and the synthesis towards analogues of discovered natural products. The following part (chapter four) was to assess antioxidant activities of synthetic compounds and investigate their SAR (structure-activity relationship), by use of a developed DPPH assay. The last part (chapter five to six) was the discovery of an abiotic halogenation reaction among a class of fungal metabolites, azaphilones. A series of their synthetic analogues were applied as model compounds to understand the mechanism of the discovered unusual and facile non-enzymatic nucleophilic halogenation reaction. Chapter one is a review of antioxidants in mushrooms. The components with antioxidant activities discovered from mushrooms were summarised by their chemical structures and representative samples were listed. In addition, the potential mechanisms of those antioxidants were described in this chapter. In chapter two, extracts of 20 mushrooms from PNG (Papua New Guinea) were screened against both Gram-positive and Gram-negative bacteria, six of them were chosen as chemical survey candidates for their strong antibacterial activities. Extracts of 37 PNG mushrooms were screened for their antioxidant using a modified DPPH assay, 14 of them were chosen as chemical survey candidates based on their antioxidant capacities. In chemical examination guided by bioactivity, five natural products including two novel furan fatty acids (2.1-2.2) and three known compounds, i.e. grifolin (2.3), grifolic acid (2.4) and grifolic acid methyl ether (2.5), were isolated from four selected mushroom samples. Chapter three described the synthetic efforts towards analogues of three isolated antioxidant fungal metabolites (2.3-2.5). Inspired by 15 synthetic targets, a short and versatile general synthetic route was established to deliver 40 compounds possessing structures related to the natural products. Based on these structures, a compound library was established for antioxidant assessment in the following SAR research. The synthetic work resulted in the preparation of 33 novel structures. In chapter four, various antioxidant assays and their working mechanisms were reviewed, as well as their corresponding advantages and drawbacks. A developed DPPH assay was optimised to offer an accurate and reproducible antioxidant evaluation for SAR research in the achieved compound library. The results indicated that a structure with an aromatic ring to be allylated with a carbon chain in addition to the presence of phenols, is required to show an antioxidant activity, and the increased length of a carbon chain (more prenyl units) enhances the antioxidant activity. Chapter five focused on naturally occurring organohalogen compounds with biotic origins. The representative halogenated natural products with a variety of bioactivities were categorised following a chemical structural classification as well as a bioactive classification, to showcase both their structural diversity and bioactive variety. The biosynthetic mechanisms of halogenated natural products were reviewed in this chapter. Chapter six detailed the investigation of a novel halogenation reaction that was discovered to be occurring with some azaphilone fungal metabolites, for example the conversion of (+)-deschlorosclerotiorin (6.2) into (+)-sclerotiorin (6.1). Various non-halogenated model compounds with an azaphilone core structure were created to shed light on the authenticity of numerous halogenated azaphilones reported as natural products. The ensuing synthetic work resulted in an efficient general procedure producing the required targets. The following investigation of the halogenation revealed a novel, facile, non-enzymatic nucleophilic reaction and its proposed mechanism is discussed. The synthetic efforts resulted in the creation of 22 novel structures.