Letteratura scientifica selezionata sul tema "Quercetin"
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Articoli di riviste sul tema "Quercetin"
1
Jang, Ae-Ra, Jun-Sang Ham, Dong-Wook Kim, Hyun-Seok Chae, Dong-Wook Kim, Sang-Ho Kim, Kuk-Hwan Seol, Mi-Hwa Oh e Dong-Hun Kim. "Effect of Quercetin and Methoxylated Quercetin on Chicken Thigh Meat Quality during Cold Storage". Korean Journal of Poultry Science 38, n. 4 (31 dicembre 2011): 265–73. http://dx.doi.org/10.5536/kjps.2011.38.4.265.
Testo completo
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Preethi, Arul Murugan, e Jayesh R. Bellare. "Concomitant Effect of Quercetin- and Magnesium-Doped Calcium Silicate on the Osteogenic and Antibacterial Activity of Scaffolds for Bone Regeneration". Antibiotics 10, n. 10 (27 settembre 2021): 1170. http://dx.doi.org/10.3390/antibiotics10101170.
Testo completoAbstract (sommario):
Quercetin is a bioflavonoid which has a broad spectrum of biological activity. Due to its lower chemical stability, it is usually encapsulated, or a metal–quercetin complex is formed to enhance its biological activity at a lower concentration. Here, our novel approach was to form a quercetin complex to magnesium-doped calcium silicate (CMS) ceramics through a coprecipitation technique so as to take advantage of quercetin’s antibacterial activity within the antibacterial and osteogenic potential of the silicate. Due to quercetin’s inherent metal-chelating ability, (Ca+Mg)/Si increased with quercetin concentration. Quercetin in magnesium-doped calcium silicate ceramic showed concentration-dependent pro-oxidant and antioxidant activity in SaOS-2 with respect to quercetin concentration. By optimizing the relative concentration, we were able to achieve 3-fold higher proliferation and 1.6-fold higher total collagen at day 14, and a 1.7-fold higher alkaline phosphatase production at day 7 with respect to polycaprolactone/polyvinylpyrrolidone (PCL/PVP) scaffold. Quercetin is effective against Gram-positive bacteria such as S. aureus. Quercetin is coupled with CMS provided similar effect with lower quercetin concentration than quercetin alone. Quercetin reduced bacterial adhesion, proliferation and biofilm formation. Therefore, quercetin-coupled magnesium-doped calcium silicate not only enhanced osteogenic potential, but also reduced bacterial adhesion and proliferation.
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Shabana, R. C. Jaysree e Rajendran N. "Review on the Bioactivities of Quercetin". International Journal of ChemTech Research 13, n. 3 (2020): 181–94. http://dx.doi.org/10.20902/ijctr.2019.130315.
Testo completoAbstract (sommario):
Quercetin, the most active bioflavonoid which is produced as a secondary metabolite by plants, is a polyphenol with a wide spectrum of bioactivities. This bioflavonoid is the ―nature‘s biological response modifier‖ as it interferes with the various allergens and other reactive compounds. Apple, oranges, tomatoes, onions, black tea and green tea are good sources of quercetin and it is also available commercially. After absorption in the small intestine and colon, quercetin conjugates with glucuronic acid and binds to albumin and passes to liver and benefits the body by its various bioactivities. Quercetin‘s antioxidant activity enhances the radical scavenging activity and metal chelation of the ions but the prooxidant activity depends on its high concentration. Further, quercetin interferes with the formation of leukotrienes from arachidonic acid showing its anti-inflammatory effect. A combined effect of quercetin and bromelain effectively suppresses the allergic reactions and the excessive inflammation resulting from bruising and tissue damage. The mutualistic effect of vitamin C and quercetin protects each other from getting oxidized. A direct relationship was also found to exist between quercetin's antiviral activity and enhancement of cyclic adenosine monophosphate (cAMP), which is a second messenger involved in many biological processes. Quercetin helps in down regulation of mutant gene p53 and inhibits the growth of cancerous cells by putting a check at G1 phase. This also controls the surpassing of the normal regulatory growth by the tumor cells and inhibits the production of heat shock proteins and thus showing its anticancer properties. Owing to the potential pharmaceutical properties of quercetin, the bioactivities, principle uses and mechanisms involved in the treatment of various diseases were reviewed in this paper. In addition, safety issues involved in the partake of quercetin by humans have also been discussed.
4
Ding, Kaixi, Wei Jiang, Wenling Zhan, Chunping Xiong, Jieling Chen, Yu Wang, Huanan Jia e Ming Lei. "The therapeutic potential of quercetin for cigarette smoking–induced chronic obstructive pulmonary disease: a narrative review". Therapeutic Advances in Respiratory Disease 17 (gennaio 2023): 175346662311708. http://dx.doi.org/10.1177/17534666231170800.
Testo completoAbstract (sommario):
Quercetin is a flavonoid with antioxidant and anti-inflammatory properties. Quercetin has potentially beneficial therapeutic effects for several diseases, including cigarette smoking–induced chronic obstructive pulmonary disease (CS-COPD). Many studies have shown that quercetin’s antioxidant and anti-inflammatory properties have positive therapeutic potential for CS-COPD. In addition, quercetin’s immunomodulatory, anti-cellular senescence, mitochondrial autophagy–modulating, and gut microbiota–modulating effects may also have therapeutic value for CS-COPD. However, there appears to be no review of the possible mechanisms of quercetin for treating CS-COPD. Moreover, the combination of quercetin with common therapeutic drugs for CS-COPD needs further refinement. Therefore, in this article, after introducing the definition and metabolism of quercetin, and its safety, we comprehensively presented the pathogenesis of CS-COPD related to oxidative stress, inflammation, immunity, cellular senescence, mitochondrial autophagy, and gut microbiota. We then reviewed quercetin’s anti-CS-COPD effects, performed by influencing these mechanisms. Finally, we explored the possibility of using quercetin with commonly used drugs for treating CS-COPD, providing a basis for future screening of excellent drug combinations for treating CS-COPD. This review has provided meaningful information on quercetin’s mechanisms and clinical use in treating CS-COPD.
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Osterc, G., M. Štefančič, A. Solar e F. Štampar. "Potential involvement of flavonoids in the rooting response of chestnut hybrid (Castanea crenata × Castanea sativa) clones". Australian Journal of Experimental Agriculture 47, n. 1 (2007): 96. http://dx.doi.org/10.1071/ea05149.
Testo completoAbstract (sommario):
The involvement of different quercetins [quercetin-3-O-rhamnoside (quercitrin), quercetin-3-D-galactoside (hyperoside) and rutin] and catechins (catechin, catechol) in the rooting process of leafy cuttings was studied in two hybrid chestnut (Castanea crenata × Castanea sativa) clones, Maraval and Marsol. Both clones differed strongly in rooting results. The Maraval clone cuttings, which had a high rooting rate, contained, on average, higher amounts of all quercetins in different plant parts (leaves and basal cuttings) than the Marsol clone, which had a low rooting rate. There was a highly significant correlation between the quercetin contents of the cutting leaves and the rooting process (number of main roots). The catecechin contents of the cutting leaves did not show any correlation with the rooting process.
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Chen, Nannan, Yu Liu, Tongtong Bai, Jinwei Chen, Zhibo Zhao, Jing Li, Baihui Shao et al. "Quercetin Inhibits Hsp70 Blocking of Bovine Viral Diarrhea Virus Infection and Replication in the Early Stage of Virus Infection". Viruses 14, n. 11 (26 ottobre 2022): 2365. http://dx.doi.org/10.3390/v14112365.
Testo completoAbstract (sommario):
Bovine viral diarrhea virus (BVDV), a positive-strand RNA virus of the genus Pestivirus in the Flaviviridae family, is the causative agent of viral diarrheal disease in bovine. BVDV has been used as a surrogate model for the hepatitis C virus (HCV) to evaluate the efficacy of antiviral drugs. The plant flavonol quercetin causes multiple health-promoting effects in humans and animals. It can be made into a variety of additives, and it exerts a variety of immunomodulatory effects with the potential to be used as an antiviral agent. However, quercetin’s antiviral effect and mechanism of action on BVDV are still unclear. Therefore, this study was designed to evaluate quercetin’s effect on BVDV virus replication in vitro and in vivo and elucidate its mechanism of action. A CCK-8 kit was used to analyze the toxicity of the quercetin to the MDBK cells. Western blot, qRT-PCR, TCID50, and histological analysis were used to determine the mechanism of quercetin’s anti-BVDV activity. An oxidative stress kit was used to evaluate the effects of quercetin on ROS, antioxidant enzymes, and MDA indexes. The effect of quercetin on IL-2 and IFN-γ in the serum of mice was determined by using an ELISA kit. The results showed that quercetin inhibits Hsp70, blocks BVDV infection in the early stage of virus infection and inhibits BVDV replication by inhibiting oxidative stress or ERK phosphorylation. In addition, quercetin alleviated the decrease in IFN-γ and IL-2 in the serum of BVDV-infected mice. Quercetin ameliorated BVDV-induced histopathological changes. In summary, this study demonstrated for the first time the role of Hsp70 in BVDV infection and the potential application of quercetin in treating BVDV infection.
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Yuan, Haihua, Hang Xun, Jie Wang, Jin Wang, Xi Yao e Feng Tang. "Integrated Metabolomic and Transcriptomic Analysis Reveals the Underlying Antibacterial Mechanisms of the Phytonutrient Quercetin-Induced Fatty Acids Alteration in Staphylococcus aureus ATCC 27217". Molecules 29, n. 10 (11 maggio 2024): 2266. http://dx.doi.org/10.3390/molecules29102266.
Testo completoAbstract (sommario):
The utilization of natural products in food preservation represents a promising strategy for the dual benefits of controlling foodborne pathogens and enhancing the nutritional properties of foods. Among the phytonutrients, flavonoids have been shown to exert antibacterial effects by disrupting bacterial cell membrane functionality; however, the underlying molecular mechanisms remain elusive. In this study, we investigated the effect of quercetin on the cell membrane permeability of Staphylococcus aureus ATCC 27217. A combined metabolomic and transcriptomic approach was adopted to examine the regulatory mechanism of quercetin with respect to the fatty acid composition and associated genes. Kinetic analysis and molecular docking simulations were conducted to assess quercetin’s inhibition of β-ketoacyl-acyl carrier protein reductase (FabG), a potential target in the bacterial fatty acid biosynthesis pathway. Metabolomic and transcriptomic results showed that quercetin increased the ratio of unsaturated to saturated fatty acids and the levels of membrane phospholipids. The bacteria reacted to quercetin-induced stress by attempting to enhance fatty acid biosynthesis; however, quercetin directly inhibited FabG activity, thereby disrupting bacterial fatty acid biosynthesis. These findings provide new insights into the mechanism of quercetin’s effects on bacterial cell membranes and suggest potential applications for quercetin in bacterial inhibition.
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Buljeta, Ivana, Ina Ćorković, Anita Pichler, Josip Šimunović e Mirela Kopjar. "Application of Citrus and Apple Fibers for Formulation of Quercetin/Fiber Aggregates: Impact of Quercetin Concentration". Plants 11, n. 24 (19 dicembre 2022): 3582. http://dx.doi.org/10.3390/plants11243582.
Testo completoAbstract (sommario):
Among flavonoids, quercetin has gained special attention due to its positive biological activities. Quercetin’s disadvantages, such as its hydrophobic nature, poor solubility, and permeability, could be overcome by complexation with different polymers. Dietary fibers are known as carriers of polyphenols, which can protect them from environmental conditions and thus allow them to be absorbed. In this study, apple and citrus fibers (as applicable food by-products) were used as carriers of quercetin. A constant amount of fibers (1%) and different concentrations of quercetin solution (5 mM, 10 mM, and 20 mM) were complexed. Obtained fiber aggregates were subjected to HPLC to determine the quercetin concentration and antioxidant activity of aggregates (ABTS, DPPH, FRAP, and CUPRAC assays). IR spectra were recorded to confirm complexation of quercetin with selected fibers, and an additional DSC study was performed to evaluate the thermal stability of fiber aggregates. The results of HPLC analysis showed that quercetin had higher affinity towards apple fiber than citrus fiber, without proportional trends of adsorption. Consequently, apple fiber aggregates had higher antioxidant potential than citrus fiber aggregates. FTIR-ATR analysis showed the formation of new bands and the loss of existing bands when quercetin was present. Adsorption of quercetin also had an impact on the thermal stability of formulated fiber aggregates. For apple fiber, this impact was negative, while for citrus fiber, the impact was positive. These results could contribute to greater understanding of quercetin’s behavior during the preparation of food additives based on polyphenols and fibers.
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Li, Xiu-Mei, Zhong-Yuan Li, Ya-Dong Wang, Jin-Quan Wang e Pei-Long Yang. "Quercetin Inhibits the Proliferation and Aflatoxins Biosynthesis of Aspergillus flavus". Toxins 11, n. 3 (9 marzo 2019): 154. http://dx.doi.org/10.3390/toxins11030154.
Testo completoAbstract (sommario):
In this work of quercetin’s anti-proliferation action on A. flavus, we revealed that quercetin can effectively hamper the proliferation of A. flavus in dose-effect and time-effect relationships. We tested whether quercetin induced apoptosis in A. flavus via various detection methods, such as phosphatidylserine externalization and Hoechst 33342 staining. The results showed that quercetin had no effect on phosphatidylserine externalization and cell nucleus in A. flavus. Simultaneously, quercetin reduced the levels of reactive oxygen species (ROS). For a better understanding of the molecular mechanism of the A. flavus response to quercetin, the RNA-Seq was used to explore the transcriptomic profiles of A. flavus. According to transcriptome sequencing data, quercetin inhibits the proliferation and aflatoxin biosynthesis by regulating the expression of development-related genes and aflatoxin production-related genes. These results will provide some theoretical basis for quercetin as an anti-mildew agent resource.
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Wang, Yu Jie, e Bing Wang. "Preparation of Quercetin-Ni+2 Metal-Complexing Imprinted Polymer and its Recognition Performance Evaluation". Applied Mechanics and Materials 275-277 (gennaio 2013): 1697–700. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.1697.
Testo completoAbstract (sommario):
Using the complex of quercetin and Ni+2 (quercetin-Ni+2) as template (quercetin is a kind of flavonoids which are important active ingredients of Chinese herbs.), methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linker, metal-complexing template polymer has been prepared in the mixed solution of methanol and tetrahydrofuran by molecular imprinting technique. The coordination structure and complex ratio between quercetin and Ni+2 were studied by UV-visible spectroscopy, and the ternary complexation of quercetin, Ni+2 and methacrylic acid was verified by similar methods. Selective adsorption experiments for substrates indicated that compared with quercetin’s structural analogs (baicalein and baringenin), quercetin-Ni+2 template polymer prepared with appropriate amount of cross-linker exhibited significant adsorption selectivity for quercetin in the presence of Ni+2. The separation factors were 3.915 and 5.443 respectively, which also showed that adsorption capacity was greatly influenced by the amount of cross-linker.
Tesi sul tema "Quercetin"
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Camargo, Mariana Santoro de. "Efeito da quercetina sobre alguns fatores relacionados com a virulência de Staphylococcus aureus /". Araraquara : [s.n.], 2008. http://hdl.handle.net/11449/94814.
Testo completoAbstract (sommario):
Orientador: Maria Stella Gonçalves RaddiBanca: Mariza Landgraf
Banca: Karina Ferrazzoli Devienne
Resumo: Esse estudo foi realizado com o objetivo de avaliar o efeito da concentração subinibitória de quercetina sobre alguns fatores relacionados à virulência de Staphylococcus aureus (ATCC 25923). A atividade antibacteriana foi determinada através do método de microdiluição em caldo e a concentração de 40μg/mL de quercetina foi utilizada como sub-inibitória. O sobrenadante de culturas de S. aureus em BHI contendo quercetina diminuiu a atividade hemolítica para hemácias de carneiro mas não alterou a atividade de citolisinas extracelulares para células de linhagem contínua (células McCoy B ATCC 1696) quando comparado com o sobrenadante da cultura na ausência do flavonol. O efeito da quercetina na fagocitose do S. aureus por polimorfonucleares neutrófilos (PMN) foi determinado através de técnica quimiluminescente. O burst oxidativo de PMN foi estatisticamente significativo para bactérias tratadas em relação às não tratadas, demonstrando que S. aureus crescidos na presença de quercetina tornam-se menos susceptíveis à fagocitose. A inibição da expressão de fatores relacionados à adesão bacteriana foi evidenciada através dos experimentos de fagocitose/adesão em microscopia óptica (1.000x). Mesmo que a quercetina, abaixo da concentração inibitória, tenha pouco efeito sobre a viabilidade de S. aureus, o conhecimento de que esse flavonol é capaz de alterar a adesão de estafilicocos à superfície celular parece ser atrativo para a sua utilização como profilático em processos infecciosos, visto que a adesão é o primeiro passo na patogênese da infecção bacteriana. Entretanto, deve-se considerar sua interferência com a atividade de células fagocíticas, uma importante função do sistema imune do hospedeiro.
Abstract: The aim of this study was to evaluate the effects of quercetin at sub-inhibitory concentration on some Staphylococcus aureus (ATCC 25923) factors related to the virulence. The antibacterial activity of quercetin was evaluated by broth microdilution method and the concentration of 40 μg/mL was used as sub- inhibitory. S. aureus BHI culture supernatant containing quercetin reduced the hemolytic activity for sheep erythrocytes but did not exhibit a detectable change in cytolysin extracellular activity on continuous cell lines (McCoy B cells ATCC 1696) when compared with quercetin-free medium. The effect of quercetin-grown staphylococci phagocytosis by polymorphonuclear neutrophils (PMN) was compared with the effect on non-treated bacteria by chemiluminescence assay. The level of oxidative burst of PMN was statistically different in untreated versus quercetin-treated bacteria showing that druggrown cells became less susceptible to phagocytic uptake. The inhibition of expression of factors related bacterial adhesion was established though adesion/phagocytosis experiments by optical microscopy (1.000x). Even if quercetin at low level has little effect on S. aureus viability, the knowledge that this flavonol is able to affect the properties of staphylococci adherence to cell surfaces may be an attractive advance for its applications as prophylactic in infectious process, considering that bacterial adherence is the initial event in the pathogenesis of bacterial infection. Conversely, it also interferes with the activities of phagocytic cells, an important function of host immune system.
Mestre
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Alves, Nelson Mendes. "Atenuação da radionecrose em ratos Wistar com aplicação cutânea de quercetina". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-18032016-093140/.
Testo completoAbstract (sommario):
O aumento da incidência de câncer tem sido expressivo nas ultimas décadas na população mundial, sendo confirmada segundo previsões de entidades nacionais e internacionais da área da saúde. O surgimento do câncer é influenciado predominantemente por fatores genéticos e ambientais, sendo manifestado com mais intensidade na população adulta. As principais modalidades para tratamento do câncer (radioterapia, quimioterapia e cirurgia) podem ser usadas individualmente ou em combinação, dependendo do tipo de câncer. Entre as modalidades citadas, a radioterapia é aquela com maior abrangência no tratamento de pacientes, tendo associado um efeito colateral denominado radiodermite que possui graus de severidade que variam de um simples eritema até radionecrose. As manifestações da radiodermite poderão ocorrer durante o tratamento ou após as seções de radioterapia, ambas as situações terão grande relevância na qualidade de vida do paciente e no custo social. Uma das terapias alternativas estudadas para atenuar a radionecrose é a aplicação cutânea de quercetina. Para avaliar a efetividade desta atenuação foi elaborado um modelo animal de radionecrose a ser utilizado em ratos Wistar. Após estudos in vitro, foi possível determinar as concentrações e momento de aplicação da quercetina, redundo o número de animais a serem utilizados nos experimentos in vivo. Com a aplicação tópica de 250 mol/L de quercetina, uma hora antes da irradiação gama com dose de 85 Gy, foi possível minimizar os efeitos secundários da radiação, evitando a formação de radionecrose e uma tendência de atenuar a área da ferida nos animais estudados, em comparação aos animais irradiados sem a aplicação da mesma.The increased incidence of cancer has been significant in recent decades in the world population, as confirmed by national and international institutions in the health area. The emergence of cancer is influenced, predominantly by genetic and environmental factors, being manifested more in the adult population. The main modalities for cancer treatment (radiotherapy, chemotherapy and surgery) may be used separately or in combination, depending on the type of cancer. Among the methods mentioned, radiation therapy is the one more broadly used for the treatment of patients, having an associated side effect called radiodermatitis, which has degrees of severity ranging from simple erythema to radionecrosis. The manifestation of radiodermatitis may occur during the treatment or after the radiotherapy sessions: both situations have great relevance in the patient\'s quality of life and social costs. One of the studied alternative therapies for attenuating the radionecrosis is the quercetin cutaneous application. One of the alternative therapies, studied to mitigate or eliminate the radionecrosis, is based on the topical application of quercetin. To evaluate the effectiveness of this mitigation, an animal model of radionecrosis was developed, to be used in Wistar rats. After in vitro studies, the quercetin concentrations and time of application were determined, reducing the number of animals, when in vivo experiments are carried out. With the topical application of 250 mol/L of quercetin, one hour prior to gamma irradiation, at a dose of 85 Gy, the side effects of radiation were minimized, avoiding the formation of radionecrosis. There was, also, a tendency to attenuate the wound area in the studied animals, compared to the irradiated animals without the quercetin application.
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Lopes, Bruno Rafael Pereira [UNESP]. "Avaliação da atividade anti-hRSV da quercetina e seus derivados acetilados". Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/138577.
Testo completoAbstract (sommario):
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
No mundo, estima-se que exista cerca de 12 milhões de casos graves e 3 milhões de casos muito graves de infecção do trato respiratório inferior em crianças anualmente. Dentre os agentes etiológicos destas infecções, o vírus sincicial respiratório humano (hRSV) é a principal causa de internações infantis em países desenvolvidos, agravando os casos de bronquiolite, pneumonia e infecções pulmonares obstrutivas crônicas em pessoas de todas as idades, principalmente crianças e idosos. Estudos preliminares demonstraram que a Quercetina possui ação virucida sobre hRSV, além de inibir sua replicação. Entretanto, não se tem conhecimento do quão promissora é a atividade antiviral de Quercetina sobre o vírus hRSV ou mesmo se esta atividade poderia ser melhorada através de mudanças químicas em sua estrutura molecular. Assim, o objetivo deste trabalho foi estabelecer o índice de seletividade (IS) para Quercetina e seus derivados acetilados durante a infeção por hRSV através de ensaios in vitro. A análise de viabilidade celular através da adição do sal de MTT determinou os valores de CC50 para Quercetina na presença/ausência do vermelho de fenol (85 e 11,4 µM, respectivamente). Dentre as condições testadas, Quercetina apresentou atividade virucida (16-30% de proteção celular) sem apresentar efeitos no pré ou pós-tratamentos. Os valores de CC50 dos compostos derivados Q1 e Q2 foram 37,1 µM e 53,15 µM, respectivamente. O composto Q1 apresentou atividade anti-hRSV nos protocolos virucida e pós-tratamento (60-90%; 4-8 µM). O composto Q2 não apresentou atividade anti-hRSV relevante em nenhuma das condições testadas. A proteção celular apresentada pela Quercetina não possibilitou o cálculo de IS (CC50/CE50) o que nos sugere que este composto não seja um promissor agente anti-hRSV. Os índices de Seletividade calculados para o composto Q1 nos protocolos virucida e pós-tratamento foi de 9,27. O conjunto de resultados obtidos neste trabalho apresenta menor citotoxicidade e melhor performance anti-hRSV do composto Q1 em relação à Quercetina comercial. Estes dados nos estimulam a dar continuidade aos estudos do composto Q1 com o intuito de melhorarmos sua atividade antiviral e assim propormos um novo composto que seja efetivos na prevenção e/ou tratamento das infecções por hRSV.
Worldwide, is estimated that there are about 12 million serious cases and 3 million severe cases of lower respiratory tract infection in children every year. Among the etiological agents of these infections, respiratory syncytial virus (hRSV) is the leading cause of children's hospitalizations in developed countries, aggravating cases of bronchiolitis, pneumonia and chronic obstructive pulmonary infections in people of all ages, especially children and the elderly. Preliminary studies demonstrated that Quercetin has virucidal action on hRSV, and inhibits replication. However, we do not know how promising is the antiviral activity of Quercetin on the hRSV. The objectives of this work is to understand the action of Quercetin and some of its derivatives acetylated on the steps of the replicative cycle of hRSV, determining the selectivity index for each compound. The development of this project will assist in the search for effective compounds in the prevention and/or treatment of hRSV infections. In the cytotoxicity assays, Quercetin showed CC50 values variable depending on the presence/absence of phenol red (11.4 and 85 μM respectively). Among the concentrations tested Quercetin only showed a slight virucidal activity (16-30% concentration 5-10 μM). The CC50 values were derived compounds 37.1 μM for Q1 and Q2 to 53.15 μM. Compound Q1 showed anti-hRSV activity in virucidal and post-treatment protocol (60-90% at 4-8 μM). The Q2 compound showed no anti-hRSV relevant activity. The presence or absence of phenol red had great influence in determining the CC50 values of Quercetin (11.4 μM and 85 μM with phenol red). In addition, Quercetin showed little (virucidal protocol without phenol) or no anti-hRSV activity. Thus it has not been possible to establish the EC50 of Quercetin and determine its selectivity index (SI). The Q1 compound showed a greater CC50 value (37.1 μM) and relevant anti-hRSV activity in post-treatment and virucidal protocols (SI 9.27). Among the compounds tested, Q2 showed the highest value of CC50 (53.15 μM without phenol) however, had little or no anti-hRSV activity, making it impossible to determine their SI.
4
Lopes, Bruno Rafael Pereira. "Avaliação da atividade anti-hRSV da quercetina e seus derivados acetilados /". Assis, 2016. http://hdl.handle.net/11449/138577.
Testo completoAbstract (sommario):
Orientadora: Karina Alves de ToledoBanca: Valéria Marta Gomes do Nascimento
Banca: Fátima Pereira de Souza
Resumo: No mundo, estima-se que exista cerca de 12 milhões de casos graves e 3 milhões de casos muito graves de infecção do trato respiratório inferior em crianças anualmente. Dentre os agentes etiológicos destas infecções, o vírus sincicial respiratório humano (hRSV) é a principal causa de internações infantis em países desenvolvidos, agravando os casos de bronquiolite, pneumonia e infecções pulmonares obstrutivas crônicas em pessoas de todas as idades, principalmente crianças e idosos. Estudos preliminares demonstraram que a Quercetina possui ação virucida sobre hRSV, além de inibir sua replicação. Entretanto, não se tem conhecimento do quão promissora é a atividade antiviral de Quercetina sobre o vírus hRSV ou mesmo se esta atividade poderia ser melhorada através de mudanças químicas em sua estrutura molecular. Assim, o objetivo deste trabalho foi estabelecer o índice de seletividade (IS) para Quercetina e seus derivados acetilados durante a infeção por hRSV através de ensaios in vitro. A análise de viabilidade celular através da adição do sal de MTT determinou os valores de CC50 para Quercetina na presença/ausência do vermelho de fenol (85 e 11,4 µM, respectivamente). Dentre as condições testadas, Quercetina apresentou atividade virucida (16-30% de proteção celular) sem apresentar efeitos no pré ou pós-tratamentos. Os valores de CC50 dos compostos derivados Q1 e Q2 foram 37,1 µM e 53,15 µM, respectivamente. O composto Q1 apresentou atividade anti-hRSV nos protocolos virucida e pó... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Worldwide, is estimated that there are about 12 million serious cases and 3 million severe cases of lower respiratory tract infection in children every year. Among the etiological agents of these infections, respiratory syncytial virus (hRSV) is the leading cause of children's hospitalizations in developed countries, aggravating cases of bronchiolitis, pneumonia and chronic obstructive pulmonary infections in people of all ages, especially children and the elderly. Preliminary studies demonstrated that Quercetin has virucidal action on hRSV, and inhibits replication. However, we do not know how promising is the antiviral activity of Quercetin on the hRSV. The objectives of this work is to understand the action of Quercetin and some of its derivatives acetylated on the steps of the replicative cycle of hRSV, determining the selectivity index for each compound. The development of this project will assist in the search for effective compounds in the prevention and/or treatment of hRSV infections. In the cytotoxicity assays, Quercetin showed CC50 values variable depending on the presence/absence of phenol red (11.4 and 85 μM respectively). Among the concentrations tested Quercetin only showed a slight virucidal activity (16-30% concentration 5-10 μM). The CC50 values were derived compounds 37.1 μM for Q1 and Q2 to 53.15 μM. Compound Q1 showed anti-hRSV activity in virucidal and post-treatment protocol (60-90% at 4-8 μM). The Q2 compound showed no anti-hRSV relevant activity. The ... (Complete abstract click electronic access below)
Mestre
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Gaeta, Henrique Hessel. "Avaliação de compostos polifenólicos nos efeitos induzidos pela sPLA2 de veneno cortálico e botrópico". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153495.
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A explosão respiratória está fortemente associada ao processo inflamatório, uma vez que diversos compostos antioxidantes estão envolvidos na potencialização ou neutralização deste processo. Diversos peróxidos inorgânicos e orgânicos são produzidos durante esse processo, como os hidroperóxidos de lipídio. Hidroperóxidos de lipídio são estáveis, extremamente reativos e podem induzir a apoptose celular. Tais lipídios modificados podem ser produzidos durante o processo inflamatório induzido pelas fosfolipases A2 (PLA2) que constituem o veneno de serpentes, que possui como consequência de sua atividade catalítica a produção de ácido araquidônico pela quebra de fosfolipídios de membrana, e estes então seriam oxidados por espécies reativas de oxigênio (ROS), formando os hidroperóxidos araquidônicos, que agravam o quadro inflamatório. Deste modo, nesse trabalho avaliamos o efeito protetor de compostos polifenólicos e extratos ricos em tais compostos de diferentes espécies vegetais no curso da inflamação e miotoxidade e no efeito inflamatório pró-oxidante induzido pela PLA2 purificada de veneno crotálico e botrópico. Nossos resultados mostraram que diversos compostos polifenólicos são capazes de diminuir os efeitos provocados pela PLA2, interagindo diretamente, inibindo a enzima e possivelmente atuando na captura de ROS.
Respiratory burst is strongly associated with inflammatory process, since several antioxidant compounds are involved in potentiation or neutralization of this process. Various inorganic and organic peroxides are produced during this process such as lipid hydroperoxides. Lipid hydroperoxides are stable, highly reactive and can induce cellular apoptosis. Such modified lipids can be produced during the inflammatory process induced by phospholipases A2 (PLA2) which are present in snake venom, and produces, because of its catalytic activity, arachidonic acid by the breakdown of membrane phospholipids, and these would then be oxidized by reactive oxygen species (ROS), forming the arachidonic hydroperoxides, which aggravates inflammation. Thus, in this work we evaluated the protective effect of polyphenolic compounds and extracts rich in such compounds of different plant species throughout the inflammation and myotoxicity and in pro-oxidant effect induced by PLA2 purified from bothrops and crotalus venom. Our results showed that polyphenolic compounds can decrease effects caused by PLA2, by directly interaction, inhibiting the enzyme and possible acting to capture ROS.
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Behm, Norma. "Einfluss des Flavonols Quercetin auf ausgewählte Parameter des Energiestoffwechsels bei fettreich ernährten Ratten". Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/997031263/04.
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Freitas, Thiago Carrazoni de. "Caracterização da atividade entomotóxica induzida pelo extrato metanólico de araucaria angustifolia em baratas da espécie phoetalia pallida". Universidade Federal do Pampa, 2012. http://dspace.unipampa.edu.br:8080/jspui/handle/riu/3862.
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Caracterização da atividade entomotóxica induzida pelo extrato metanólico de araucaria angustifolia em baratas da espécie phoetalia pallida.pdf: 1288498 bytes, checksum: 743a39a2337c5be31393482af81a2fb6 (MD5)Made available in DSpace on 2019-03-26T18:42:21Z (GMT). No. of bitstreams: 1 Caracterização da atividade entomotóxica induzida pelo extrato metanólico de araucaria angustifolia em baratas da espécie phoetalia pallida.pdf: 1288498 bytes, checksum: 743a39a2337c5be31393482af81a2fb6 (MD5) Previous issue date: 2012-01-05
Neste trabalho foi demostrado, pela primeira vez, a atividade inseticida do extrato metanólico de Arauacaria angustifolia (Bert.) O. Kuntze 1898 (AAME) e seu metabólito secundário, a quercetina, em baratas da espécie Phoetalia pallida. A investigação fitoquímica preliminar, realizada através da Cromatografia em Camada Delgada (CCD), demonstrou a presença do flavonóide quercetina no AAME. A confirmação da presença da quercetina no extrato foi obtida por Cromatografia Líquida de Alta Eficiência (HPLC), com tempo de retenção em 10.6min. A determinação de fenólicos totais indicou uma alta concentração destes compostos (1,03%) no AAME. Os ensaios para a determinação da dose letal mínima (DLM) em baratas da espécie P. pallida, confirmaram a atividade inseticida do extrato em doses a partir de (800g/g de animal). A mesma atividade foi demonstrada pela quercetina (80μg/g), porém, com maior potência comparada ao AAME. Ambos, AAME (200μg/g) e quercetina (40μg/g) foram eficazes em bloquear significativamente a atividade da enzima acetilcolinesterase no inseto. Os ensaios de atividade biológica demonstram uma atividade neurotóxica do AAME e da quercetina, tanto em nível central quanto periférico do inseto. Dessa forma, o AAME (200μg/g) e a quercetina (40μg/g) induziram um aumento no tempo total de grooming realizado pelo inseto, (138.11±5s /30min; p<0.05 e 2305s/30min; p<0.05), respectivamente. A administração de Atropina (40μg/g), previamente à adição de quercetina (40μg/g) induziu um aumento significativo na atividade de grooming quando comparado à quercetina isoladamente (3503s/30min; p<0.05). Quando o animal foi pré-tratado com Metoctramina (40μg/g), um inibidor seletivo de receptores colinérgicos M2-M3, observou-se o maior aumento no tempo de grooming induzido pela quercetina (40μg/g) (6008s/30min; p<0.01 teste t). Por outro lado, o pré-tratamento com o SCH23390 (40μg/g), um inibidor seletivo de receptores DA-D1, reduziu significativamente o grooming induzido pela quercetina (40μg/g) (906s/30min; p<0.05). A administração de Tiramina (40μg/g) e hidroxilamina (40μg/g), um inibidor da guanilato ciclase, aumentaram significativamente o tempo de grooming induzido pela quercetina (20415s/30min; p<0.05) e (32515s/30min; p<0.01), respectivamente. Quando ensaiados em preparação músculo coxal-adutor metatorácico de P. pallida, tanto o AAME (200μg/g de animal) quando a quercetina (40μg/g) induziram bloqueio neuromuscular irreversível em 120 min de registros (50±9%; p<0.05 e 100±7%; p<0.05), respectivamente. Este último resultado indica uma ação direta do extrato de A. angustifolia sobre o Sistema Nervoso Periférico da barata. Os resultados mostrados neste trabalho validam a atividade inseticida do AAME em P. pallida. Compostos fenólicos presentes no extrato provavelmente estão envolvidos na atividade inseticida, como demonstrado pela quercetina. O mecanismo de ação inseticida é complexo, e envolve tanto a neurotoxicidade sobre o Sistema Nervoso Central quanto sobre o Periférico. A ativação de uma cascata de eventos que se inicia com a ativação de autoreceptores muscarínicos no soma dopaminérgico e/ou em interneurônios colinérgicos, induziria um aumento da concentração do IP3 citosólico bem como do Ca2+ favorecendo a liberação da dopamina no sistema nervoso central do inseto. Quanto à atividade bloqueadora neuromuscular, estudos mais detalhados usando-se moduladores farmacológicos de receptores de glutamato e do ácido-gama-aminobutírico (GABA) poderão elucidar esse efeito.
We have demonstrated, for the first time, the insecticidal activity of Araucaria angustifolia methanolic extract (AAME) and one of its chemical secondary metabolites, quercetin against Phoetalia pallida. Preliminary investigation of AAME phytochemical compounds by thin layer chromatography showed the presence of quercetin. The total phenolic contents measured by spectrophotometry showed high content of phenolic acids (1,03%). High Performance Liquid Cromatography (HPLC) proved the presence of quercetin that was eluted at 10.6min. In doses ranging from 800-1200g/g (animal weight) AAME was effective to kill all cockroaches injected after 24 hours. Quercetin was more effective than AAME whole extract being lethal at 80g/g (animal weight). Both AAME (200μg/g of animal weight) and quercetin (40μg/g of animal weight) were able to induce a significative blockage at insect acetylcholinesterase activity. these compounds also induced increase in the time of grooming activity (138.11±5s /30min; p<0.05) and (2305s/30min; p<0.05), respectively. The injection of atropine (40μg/g) combined with quercetin (40μg/g of animal weight) significantly increased the grooming levels to over the control values of quercetin (3503s/30min; p<0.05). When methoctramine (40μg/g), a selective inhibitor of M2-M3 cholinergic receptor was combined with quercetin (40μg/g of animal weight) there was the highest increase on the grooming pattern (6008s/30min; p<0.01). When the SCH 23390 (40μg/g), a selective DA-D1 receptor blocker was administrated 15min earlier the treatment with quercetin (40μg/g) there was a significative inhibition of the grooming levels (906s/30min; p<0.05). Treatments with Tyramine (40μg/g) and Hydroxylamine (40μg/g), a Guanylate Cyclase (GC) induced a significative increase in the quercetin-induced grooming activity (20415s/30min; p<0.05) and (32515s/30min; p<0.01), respectively. Both AAME and quercetin were able to complete inhibit cockroach neuromuscular transmission in 120 min recordings (50±9% n=6; p<0.05) and (100±7% n=10; p<0.05), respectively . The later result, point out to a direct action of the extract on insect peripheral nervous system. The results presented here validate the insecticide activity of A. angustifolia methanolic extract in P. pallida. Phenolic compounds presents in this extract era likely to be involved in the insecticide activity of AAME. The mechanism of insecticide activity is complex and involve both Central and Peripheral Nervous System. The activation of events that initiate with the activation of Muscarinic Auto-receptors and/or cholinergic interneurons, could lead to an increase of cytosolic IP3 and Ca2+ concentration which could induce a dopamine release in the insect Nervous System. Concerning to the neuromuscular blockage, a further pharmacological investigation would be necessary to clarify this effect. However, one cannot disregard a direct action of quercetin on insect NMDA receptors.
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Souza, Alex Jardelino Felizardo de. "Avaliação dos efeitos antimicrobianos de rutina e quercetina in vitro". [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314773.
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Orientador: Marcos Hikari ToyamaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Flavonóides é um grupo de compostos polifenólicos e metabólitos secundários produzidos por plantas. Eles podem ser encontrados em frutos e vegetais. Vários estudos têm mostrado que os flavonóides podem apresentar várias atividades biológicas importantes como agentes antioxidantes, antitumorais, antimicrobianos e ainda inibir atividade de algumas moléculas com as PLA2. Recentemente estudos mostram também que os flavonóides podem atuar em moléculas de DNA. A atividade antimicrobiana dos flavonóides é decorrente de desestruturação de membrana celular e consequentemente destruição da célula bacteriana. Neste trabalho avaliamos efeitos antimicrobianos de quercetina e rutina, que são comumente empregados como fitoterápicos. Foi observado que ambos flavonóides inibiram o crescimento de bactérias fitopatogênicas. Contudo nenhum efeito foi observado em outras linhagens de bactérias patogênicas. Os resultados de microscopia eletrônica de varredura e transmissão não evidenciaram mudanças significativas na estrutura celular de Xanthomonas axonopodis pv. passiflorae incubadas com rutina e quercetina. Tanto rutina quanto a quercetina foram capazes de promover mudanças estruturais na molécula de cDNA como observado nos resultados de HPLC. A rutina induziu discreta modificação na proteína DNA polimerase. E quercetina impediu a síntese de cDNA a partir de RNA como mostram resultados de eletroforese. Estes dados sugerem que a inibição do crescimento de Xanthomonas axonpodis pv. Passiflorae e Clavibacter michiganensis subsp. michiganensis pode envolver a ação dos flavonóides (quercetina e rutina) sobre o DNA bacteriano, mudando suas propriedades estruturais e consequentemente a replicação bacteriana. E ainda, os dados mostram que a presença da rutinose pode influenciar a forma de atuação destes flavonóides.
Abstract: Flavonoids are a group of polyfenolic compounds and secondary metabolites produced by plants. They may be found in fruits and vegetables. Several studies have shown that the flavonoids may submit several biological important activities as antioxidants agents, antitumor, antimicrobials and even inhibit activity of some molecules like the PLA2. Recently studies also show that the flavonoids may act in DNA molecules. The antimicrobial activity of flavonoids is the result of destructuring cell membrane and consequently the bacterial cell destruction. In this work we evaluated the antimicrobials effects of quercetin and rutin, which are commonly employed as phytotherapic drugs. It was observed that both flavonoids inhibited the growth of phytopathogenics bacteria. However no effect was observed in other pathogenic bacteria strains. The results of scanning electronic and transmission microscopy showed significant changes in cellular structure of Xanthomonas axonopodis pv passiflorae incubated with rutin and quercetin. Both rutin as quercetin were able to promote structural change in the molecule of cDNA as observed in the results of HPLC. The rutin induced mild changes in protein DNA polymerase. Quercetin prevented the synthesis of cDNA from RNA as showed by electrophoresis results. These data suggest that inhibition of growth of Xanthomonas axonpodis pv. passiflorae and Clavibacter michiganensis subsp. michiganensis may involve the action of flavonoids (quercetin and rutin) on bacterial DNA, changing its structural properties and consequently the bacterial replication. And yet, the data show that the presence of rutinose may influence the form of action of these flavonoids.
Mestrado
Bioquimica
Mestre em Biologia Funcional e Molecular
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Reinboth, Marianne. "Bioverfügbarkeit des Flavonols Quercetin beim Hund". Doctoral thesis, Universitätsbibliothek Leipzig, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-62483.
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6 Zusammenfassung Marianne Reinboth Bioverfügbarkeit des Flavonols Quercetin beim Hund Veterinär-Physiologisches Institut der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im Juni 2010 79 Seiten, 20 Abbildungen, 6 Tabellen, 211 Literaturangaben, 1 Anhang Schlüsselwörter: Quercetin, Bioverfügbarkeit, Hund, absolute Bioverfügbarkeit, Isoquercitrin, Rutin, Flavonole Für das pflanzliche Flavonol Quercetin werden vielfältige gesundheitsfördernde Wirkungen postuliert, so auch bei Hunden. Über die Bioverfügbarkeit des Flavonols bei dieser Spezies liegen bislang jedoch keinerlei Daten vor. Daher hatte diese Arbeit das Ziel, Bioverfügbarkeit und pharmakokinetische Parameter von Quercetin und wichtigen Quercetinglycosiden bei Hunden nach deren Verabreichung mit einer Testmahlzeit in einer praxisrelevanten Dosierung von 10 mg/kg Körpermasse zu untersuchen. Dazu erhielten 9 adulte Beagles beiderlei Geschlechts das zuckerfreie \"Aglycon\" Quercetin bzw. seine Glycoside Isoquercitrin (Quercetin-3-O-Glucosid) und Rutin (Quercetin-3-O-Glucorhamnosid) in jeweils äquimolarer Dosierung in einer Testmahlzeit verabreicht. Anschließend wurden Blutproben über einen Zeitraum von bis zu 72 Stunden entnommen und mittels HPLC die Konzentrations-Zeitverläufe der Metaboliten im Blutplasma, die Bioverfügbarkeit sowie weitere pharmakokinetische Parameter bestimmt. Weiterhin wurde die absolute Bioverfügbarkeit von Quercetin aus dem Vergleich einer oralen mit einer intravenösen Applikation bestimmt. Der weitaus größte Teil der Plasmametaboliten von Quercetin sowie seiner beiden Glycoside bestand aus glucuronidierten bzw. sulfatierten Quercetinkonjugaten. Nicht konjugiertes Quercetin-Aglycon kam nur in einem Anteil von etwa 20 % vor. Neben Quercetin machten seine Metaboliten Isorhamnetin und Kämpferol weniger als 10 % aller im Plasma zirkulierenden Flavonole aus. Die absolute Bioverfügbarkeit von Quercetin betrug nur etwa 4 %. Die relative Bioverfügbarkeit aus dem 3-O-Glucosid Isoquercitrin war mehr als doppelt so hoch wie aus dem Aglycon, die maximalen Plasmaspiegel lagen aber auch hier unter 1 µmol/l. Sowohl nach Aufnahme von Quercetin als auch nach Isoquercitrin kam es zu einer relativ schnellen Absorption aus dem Dünndarm mit einem ersten Plasmapeak ungefähr eine Stunde nach der Ingestion. Vier Stunden nach Aufnahme der beiden Flavonole trat ein zweiter Plasmapeak auf, der in der Regel höher als der erste ausfiel. Dies deutet auf einen enterohepatischen Kreislauf der über die Galle ausgeschiedenen Metaboliten hin. Nach Aufnahme von Rutin kam es zu einer verzögerten Absorption, da eine Deglycosylierung durch bakterielle Glycosidasen im Dickdarm Voraussetzung für die Absorption des Flavonols ist. Maximale Plasmakonzentrationen wurden im Mittel erst 11 Stunden nach Ingestion dieses Glycosids erreicht. Die maximalen Plasmakonzentra-tionen nach Rutin waren geringer als nach Quercetin oder Isoquercitrin, jedoch war die mittlere Verweildauer der Plasmametaboliten mit 18 Stunden auch wesentlich länger. Im Unterschied zu anderen Spezies war die relative Bioverfügbarkeit von Rutin gegenüber Quercetin nicht verringert. Obwohl Rutin eine relativ gute Quercetinquelle für Hunde zu sein scheint, muss bei der Einschätzung möglicher In-vivo-Wirkungen die relativ geringe Bioverfügbarkeit sowie die intensive Metabolisierung seines Aglycons Quercetin berücksichtigt werden7 Summary Marianne Reinboth Bioavailability of the Flavonol Quercetin in Dogs Institute of Physiology of the Faculty of Veterinary Medicine, University of Leipzig Submitted in June 2010 79 pages, 20 figures, 6 tables, 211 references, 1 appendix Keywords: quercetin, bioavailability, dog, absolute bioavailability, isoquercitrin, rutin, flavonols The plant flavonol quercetin is supposed to exert multiple health-related effects in dogs. To date no information on its bioavailability in this particular species is avai-lable. This study intended to investigate bioavailability and pharmacokinetics of quercetin and certain quercetin glycosides in dogs after ingestion of a test meal sup-plemented with a quercetin dose equivalent to 10 mg/kg body weight. Nine adult beagle dogs of both sexes received the aglycon quercetin (sugarfree) or its glycosides isoquercitrin (quercetin-3-O-glucoside) and rutin (quercetin-3-O-glucorhamnoside) in equimolar amounts together with a test meal. Blood samples were taken over a period of up to 72 hours; bioavailability and pharmacokinetics were calculated from the HPLC-derived plasmaconcentration-time-curves. Absolute bioavailability was calculated by comparing an oral to an intravenous administration of quercetin. The majority of analysed plasma metabolites were glucuronidated and sulfated con-jugates of quercetin. Non-conjugated quercetin aglycon comprised only 20 %. Be-sides quercetin, its metabolites isorhamnetin and kaempferol made up less than 10 % of all circulating metabolites. The absolute bioavailability of quercetin was only 4 %. The relative bioavailability of quercetin from isoquercitrin was more than twice as high than from the aglycon, but even there maximal plasma concentrations were generally less than 1 μmol/l. Absorption from the small intestine was rather fast with a first plasma peak after 1 hour after ingestion of quercetin or isoquercitrin. A second, generally higher plasma peak occurred 4 hours after ingestion. This suggests an in-tensive enterohepatic recycling of biliary secreted metabolites. Absorption was significantly delayed after ingestion of rutin due to the necessity of bacterial deglycosilation in the large intestine. Plasma concentrations peaked only after 11 hours. Plasma concentrations after rutin were lower than after quercetin or isoquercitrin, but mean residence time of plasma metabolites was as long as 18 hours after rutin ingestion. Consequently, a once daily feeding of dogs with rutin might lead to relatively constant plasma metabolite concentrations. In contrast to other species, bioavailability from rutin was not smaller than that from quercetin. Although rutin seems to be a relative good quercetin source for dogs, estimations about potential in-vivo-effects of quercetin have to take into consideration its low bioavailabilty and intensive metabolism
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Camargo, Mariana Santoro de [UNESP]. "Efeito da quercetina sobre alguns fatores relacionados com a virulência de Staphylococcus aureus". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/94814.
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camargo_ms_me_arafcf.pdf: 358942 bytes, checksum: 8f89d0a7367c210ee69a22ae462e0342 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Universidade Estadual Paulista (UNESP)
Esse estudo foi realizado com o objetivo de avaliar o efeito da concentração subinibitória de quercetina sobre alguns fatores relacionados à virulência de Staphylococcus aureus (ATCC 25923). A atividade antibacteriana foi determinada através do método de microdiluição em caldo e a concentração de 40μg/mL de quercetina foi utilizada como sub-inibitória. O sobrenadante de culturas de S. aureus em BHI contendo quercetina diminuiu a atividade hemolítica para hemácias de carneiro mas não alterou a atividade de citolisinas extracelulares para células de linhagem contínua (células McCoy B ATCC 1696) quando comparado com o sobrenadante da cultura na ausência do flavonol. O efeito da quercetina na fagocitose do S. aureus por polimorfonucleares neutrófilos (PMN) foi determinado através de técnica quimiluminescente. O burst oxidativo de PMN foi estatisticamente significativo para bactérias tratadas em relação às não tratadas, demonstrando que S. aureus crescidos na presença de quercetina tornam-se menos susceptíveis à fagocitose. A inibição da expressão de fatores relacionados à adesão bacteriana foi evidenciada através dos experimentos de fagocitose/adesão em microscopia óptica (1.000x). Mesmo que a quercetina, abaixo da concentração inibitória, tenha pouco efeito sobre a viabilidade de S. aureus, o conhecimento de que esse flavonol é capaz de alterar a adesão de estafilicocos à superfície celular parece ser atrativo para a sua utilização como profilático em processos infecciosos, visto que a adesão é o primeiro passo na patogênese da infecção bacteriana. Entretanto, deve-se considerar sua interferência com a atividade de células fagocíticas, uma importante função do sistema imune do hospedeiro.
The aim of this study was to evaluate the effects of quercetin at sub-inhibitory concentration on some Staphylococcus aureus (ATCC 25923) factors related to the virulence. The antibacterial activity of quercetin was evaluated by broth microdilution method and the concentration of 40 μg/mL was used as sub- inhibitory. S. aureus BHI culture supernatant containing quercetin reduced the hemolytic activity for sheep erythrocytes but did not exhibit a detectable change in cytolysin extracellular activity on continuous cell lines (McCoy B cells ATCC 1696) when compared with quercetin-free medium. The effect of quercetin-grown staphylococci phagocytosis by polymorphonuclear neutrophils (PMN) was compared with the effect on non-treated bacteria by chemiluminescence assay. The level of oxidative burst of PMN was statistically different in untreated versus quercetin-treated bacteria showing that druggrown cells became less susceptible to phagocytic uptake. The inhibition of expression of factors related bacterial adhesion was established though adesion/phagocytosis experiments by optical microscopy (1.000x). Even if quercetin at low level has little effect on S. aureus viability, the knowledge that this flavonol is able to affect the properties of staphylococci adherence to cell surfaces may be an attractive advance for its applications as prophylactic in infectious process, considering that bacterial adherence is the initial event in the pathogenesis of bacterial infection. Conversely, it also interferes with the activities of phagocytic cells, an important function of host immune system.
Libri sul tema "Quercetin"
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Quercetin: Dietary sources, functions, and health benefits. Hauppauge, N.Y: Nova Science Publishers, 2011.
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Demiroglu, Asuman. Induction of apoptosis by the bioflavonoid quercetin in myeloid leukaemia cell lines. [s.l.]: typescript, 1997.
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Musonda, Alam Clement. Quercetin as a modulator of xenobiotic metabolism and reactive oxygen species (ROS) in human hepG2 cells. Birmingham: University of Birmingham, 1998.
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Luciano, Egidi, a cura di. L'attività tipografica di Domenico Antonio Quercetti. Ancona: Il lavoro editoriale, 2007.
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Luciano, Egidi, a cura di. L'attività tipografica di Domenico Antonio Quercetti. Ancona: Il lavoro editoriale, 2007.
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Alessandro, Rinaldi, e Grifoni Tiziana, a cura di. Villa Strozzi "Il querceto" nel tempo: L'edificio, il giardino, il parco agricolo. Firenze: Alinea, 2006.
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La vita quotidiana di un campo di concentramento fascista: Ribelli sloveni nel querceto di Renicci-Anghiari (Arezzo). Roma: Carocci, 2004.
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Mood and Vigilance Following Quercetin Supplementation. Storming Media, 2002.
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Vaia, Renee L. Solubility and sensory characteristics of quercetin aglycone. 1995.
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Malone, Gregory. Quercetin: Food Sources, Antioxidant Properties and Health Effects. Nova Science Publishers, Incorporated, 2015.
Cerca il testo completoCapitoli di libri sul tema "Quercetin"
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Li, Li, Li Zhang e Guan-Hua Du. "Quercetin". In Natural Small Molecule Drugs from Plants, 725–29. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-8022-7_118.
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Leighton, Terrance, Charles Ginther, Larry Fluss, William K. Harter, Jose Cansado e Vicente Notario. "Molecular Characterization of Quercetin and Quercetin Glycosides inAlliumVegetables". In ACS Symposium Series, 220–38. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0507.ch016.
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Schomburg, Dietmar, e Dörte Stephan. "Quercetin 2,3-dioxygenase". In Enzyme Handbook, 113–15. Berlin, Heidelberg: Springer Berlin Heidelberg, 1994. http://dx.doi.org/10.1007/978-3-642-57942-4_23.
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Zhang, Mei, Steven G. Swarts, Liangjie Yin, Chaomei Liu, Yeping Tian, Yongbing Cao, Michael Swarts et al. "Antioxidant Properties of Quercetin". In Oxygen Transport to Tissue XXXII, 283–89. Boston, MA: Springer US, 2011. http://dx.doi.org/10.1007/978-1-4419-7756-4_38.
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Schomburg, Dietmar, e Dörte Stephan. "Quercetin 3-O-methyltransferase". In Enzyme Handbook 11, 325–27. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-61030-1_73.
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Deschner, Eleanor E. "Dietary Quercetin and Rutin". In ACS Symposium Series, 265–68. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0507.ch019.
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Das, Sabya Sachi, P. R. P. Verma, Sweta Kar e Sandeep Kumar Singh. "Quercetin-Loaded Nanomedicine as Oncotherapy". In Nanomedicine for Bioactives, 155–83. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-1664-1_5.
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Schomburg, Dietmar, e Dörte Stephan. "Quercetin-3-sulfate 3’-sulfotransferase". In Enzyme Handbook, 1029–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-59025-2_193.
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Schomburg, Dietmar, e Dörte Stephan. "Quercetin-3-sulfate 4’-sulfotransferase". In Enzyme Handbook, 1033–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-59025-2_194.
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Schomburg, Dietmar, e Dörte Stephan. "Quercetin-3,3’-bissulfate 7-sulfotransferase". In Enzyme Handbook, 1037–39. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-642-59025-2_195.
Testo completoAtti di convegni sul tema "Quercetin"
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Wu, Haizhou, Jie Yin e Mark Richards. "Inhibitory Mechanisms of Quercetin Against Hemoglobin-mediated Lipid Oxidation in Washed Muscle Model". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ituo9388.
Testo completoAbstract (sommario):
Lipid oxidation in fresh and further processed meat facilitates quality deterioration during storage, including loss of color, flavor, and in some cases nutritional value. Flavonoids are found ubiquitously in plants as a member of polyphenolic compounds and have received considerable attention for their antioxidant properties. Numerous studies have demonstrated that free radical scavenging and metal chelation could be the key factors responsible for the antioxidative activities of flavonols. In our previous work, a fraction isolated from cranberry juice powder was an effective inhibitor of lipid oxidation in mechanically separated turkey (MST) and washed cod muscle. The compound responsible for the inhibitory activity was then identified as quercetin. However, the mechanisms by which quercetin inhibits lipid oxidation due to heme proteins present in muscle foods has received little attention. With this background, we studied the antioxidant effect of quercetin on hemoglobin(Hb)-mediated lipid oxidation and the mechanisms involved in washed cod muscle model. Quercetin strongly inhibited Hb-mediated lipid oxidation in washed muscle. Quercetin showed effective hydroxyl radical scavenging ability similar to butylated hydroxytoluene (BHT). Quercetin reduced metHb resulting in formation of oxyHb. Bound quercetin decreased heme dissociation from metHb. Conversion to oxyHb and decreased heme dissociation represent routes to limit Hb-mediated lipid oxidation. Electrospray ionization mass spectrometry (ESI-MS) indicated one molecule of quercetin was covalently bound to Hb α-chain. Quercetin quinone docked 3.3 Å from the thiol of αCys(H15) but not near any other Cys residues of turkey Hb. At the docking site, hydrogen bonding between quercetin quinone and amino acids of α- and β-chain was demonstrated. This represents a path by which quercetin became covalently bound to α-chain. Molecular docking of heme proteins to polyphenols provides a template to better understand antioxidant interactions in muscle foods.
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Zavodnik, I. B., E. A. Lapshina, T. V. Ilyich, A. G. Veiko, T. A. Kovalenia e V. U. Buko. "REGULATORY, ANTIOXIDATIVE AND HEPATOPROTECTIVE EFFECTS OF PLANT POLYPHENOLS AND THEIR NANOSTRUCTURED COMPLEXES". In SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-255-258.
Testo completoAbstract (sommario):
Flavonoids, secondary plant metabolites, demonstrate a wide range of biological and pharmacological activities. In our experiment, flavonoids and their complexes with cyclodextrins (10—100 gM) dose-dependently prevented lipid peroxidation of erythrocyte and mitochondrial membranes, inhibited oxidation of reduced glutathione, and modulated the proapoptotic process of the mitochondrial permeability transition pores formation, that depends on flavonoid lipophilicity and structures. Generation of maps of the electron density distribution in the quercetin molecule and the quercetin semiquinone radical shows that the active electronic orbitals of quercetin and its semiquinone radical are delocalized along the phenolic rings, which, in the case of a radical, increases radical stability. The quercetin-hydroxypropyl-e-cyclodextrin complex proved to be a more effective antioxidant.
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Baba, Waqas, e Sajid Maqsood. "Enhancing techno-functional and bioactive properties of whey proteins by conjugation with quercetin using combined treatment of redox pair and ultrasonication". In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/jtxr7155.
Testo completoAbstract (sommario):
Camel whey-quercetin conjugates were fabricated via free radicals using a combination of ultrasonication treatment and a redox-pair (ascorbic acid/H2O2). Conjugation of whey with quercetin was confirmed using UV-Vis. spectroscopy, FTIR and SDS-PAGE. UV-Visible spectroscopy showed a bathochromic shift and appearance of a hump around ≈350 nm (absent in whey sample) that can be attributed to binding of quercetin with whey protein. As indicated by FTIR, the association of whey with quercetin took place via covalent (appearance of new peak at 3399 cm-1) as well as noncovalent linkages (shift-ing of peak at 3271 cm-1, 1655 cm-1 (amide I), 1534 cm-1 and 1422 cm-1 (Amide II). The appearance of new peaks in UV-Visible spectroscopy and FTIR of conjugates was resolved using a second derivative of the spectrum. Reducing SDS-PAGE revealed shifting of protein bands towards higher molecular weight due to increase in the mass of conjugates that can be attributed to covalent conjugation between whey and quercetin. A significant improvement in the functionality and bioac-tive properties was witnessed after conjugation of whey with quercetin. Ultrasonication improved the emulsifying and foaming properties while a combination of ultrasonication and redox pair method enhanced the antioxidant properties. Moreover, conjugated samples showed higher inhibition of enzymatic markers involved in diabetes (α-amylase & DPP-IV) and obesity (cholesterol esterase & lipase) with highest potential recorded for conjugates produced using ultrasonication only. Therefore, ultrasonication can be successfully used individually as well as in combination with redox-pair for produc-tion of whey-quercetin conjugates with enhanced bioactive and techno-functional properties.
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Yakovishin, L. A., e E. N. Korzh. "Molecular complex of quercetin with glycyram". In PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON AUTOMOTIVE INNOVATION GREEN ENERGY VEHICLE: AIGEV 2018. Author(s), 2019. http://dx.doi.org/10.1063/1.5087398.
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Pratama, Ferdi Henfi, e Minda Azhar. "Quercetin grafted inulin: Synthesis and characterization". In THE 5TH INTERNATIONAL CONFERENCE ON MATERIALS ENGINEERING AND NANOTECHNOLOGY (ICMEN 2021). AIP Publishing, 2023. http://dx.doi.org/10.1063/5.0125693.
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Tombak, Ahmet, C. Özaydin, M. Boğa e T. Kiliçoğlu. "Electrical characterization of Au/quercetin/n-Si heterojunction diode and optical analysis of quercetin thin film". In 9TH INTERNATIONAL PHYSICS CONFERENCE OF THE BALKAN PHYSICAL UNION (BPU-9). AIP Publishing LLC, 2016. http://dx.doi.org/10.1063/1.4944303.
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Lam, Tram K., Melissa Rotunno, Jay H. Lubin, Sholom Wacholder, Dario Consonni, Pier Alberto Bertazzi, Angela C. Pesatori et al. "Abstract A105: Dietary quercetin, quercetin‐gene interaction, metabolic gene expression in lung tissue, and lung cancer risk". In Abstracts: AACR International Conference on Frontiers in Cancer Prevention Research‐‐ Dec 6–9, 2009; Houston, TX. American Association for Cancer Research, 2010. http://dx.doi.org/10.1158/1940-6207.prev-09-a105.
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Arslanova, G. R., D. B. Prosvirnikov e R. G. Safin. "EXTRACTION OF PHENOLIC COMPOUNDS OF ASPEN AND WILLOW LEAVES OF THE SALICACEAE FAMILY". In Modern machines, equipment and IT solutions for industrial complex: theory and practice. Voronezh State University of Forestry and Technologies named after G.F. Morozov, Voronezh, Russia, 2021. http://dx.doi.org/10.34220/mmeitsic2021_17-22.
Testo completoAbstract (sommario):
The paper presents the results of studies on the extraction of phenolic compounds from the leaves of trees of the Salicaceae family, namely aspen and willow. A method for extracting phenolic compounds of salicin and quercetin by extraction using ethyl alcohol as a solvent is described. The method of identification of salicin and quercetin by thin-layer chromatography (TLC) is described. Digital processing of the obtained results was carried out using the computer program “Sorbfil Visualizer” (Krasnodar). The optimal operating parameters of the process, allowing to obtain the highest yield of the desired substances, are determined. The maximum yield of quercetin in the amount of 1.4% a. s. v. was obtained from aspen leaves, and was achieved at the following extraction parameters: the concentration of the ethyl alcohol solution (extractant) – 60%, the extraction duration-30 min, the temperature of the extractant-50°C. The maximum yield of salicin from aspen leaves is 0.26% a. s. v. and is achieved at.
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Yakovishin, L. A., V. D. Ratnikov, P. I. Bazhan, V. I. Grishkovets e E. N. Korzh. "Molecular complex of quercetin with hederasaponin C". In PROCEEDINGS OF INTERNATIONAL CONFERENCE ON RECENT TRENDS IN MECHANICAL AND MATERIALS ENGINEERING: ICRTMME 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0018048.
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Li, Chen, Zhuan-Hua Wang e Deng-Guang Yu. "Electrosprayed dual release composite microparticles of quercetin". In International Conference on Modern Engineering Soultions for the Industry. Southampton, UK: WIT Press, 2014. http://dx.doi.org/10.2495/mesi141132.
Testo completoRapporti di organizzazioni sul tema "Quercetin"
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Zheng, Jinghui. Quercetin for Myocardial Ischemia/Reperfusion Injury: A Preclinical Systematic Review and Meta-Analysis. INPLASY - International Platform of Registered Systematic Review Protocols, aprile 2020. http://dx.doi.org/10.37766/inplasy2020.4.0162.
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Lu, Liying, Xiaocong Ma, Jinghui Zheng, Lijuan Li, Wenna Yang, Yixuan Kong e Jie Wang. Quercetin for Myocardial Ischemia Reperfusion Injury: A Protocol for Systematic Review and Meta Analysis. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, maggio 2020. http://dx.doi.org/10.37766/inplasy2020.5.0067.
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Zhang, Xiaoling. Inhibitory effecT of quercetin on protein expression CtBP1 and migration of hepatocellular carcinoma cell SMMC-7721. Science Repository, giugno 2018. http://dx.doi.org/10.31487/j.cor.2018.02.001.
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van Krimpen, M. M., M. Torki, D. Schokker, M. Lensing, S. Vastenhouw, F. M. de Bree, A. Bossers et al. Effect of nutritional interventions with quercetin, oat hulls, β-glucans, lysozyme, and fish oil on immune competence related parameters of adult broiler. Wageningen: Wageningen Livestock Research, 2016. http://dx.doi.org/10.18174/390435.
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GAFNER, STEFAN. Ginkgo Leaf Extract Laboratory Guidance Document. ABC-AHP-NCNPR Botanical Adulterants Prevention Program, maggio 2022. http://dx.doi.org/10.59520/bapp.lgd/zuyx3621.
Testo completoAbstract (sommario):
Adulteration of ginkgo leaf extracts with extracts from flavonol-rich extracts from sources such as Japanese sophora is well documented in the literature. The partial or complete substitution of ginkgo extracts with flavonol-rich ingredients, or highly purified flavonoids (e.g., quercetin or rutin) from other sources (Table 1) was documented as early as 2003, and has been evidenced in over 20 peer-reviewed publications since. This Laboratory Guidance Document (LGD) presents a review of the various analytical methods used to differentiate between authentic ginkgo leaf extracts and ingredients containing adulterating materials. This document can be used in conjunction with the Ginkgo biloba leaf extract Botanical Adulterants Prevention Bulletin published by the ABC-AHP-NCNPR Botanical Adulterants Prevention Program in 2018 and the AHP Ginkgo Monograph and Therapeutic Compendium.
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Phillips, Donald, e Yoram Kapulnik. Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi. United States Department of Agriculture, gennaio 1995. http://dx.doi.org/10.32747/1995.7613012.bard.
Testo completoAbstract (sommario):
Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions