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Phenolic compounds and antioxidant activity of two regions Portugal propolis

Moreira, Leandro; Pereira, Ermelinda; Dias, L.G.; Pires, Sância; Estevinho, Leticia M.
Fonte: Jennifer Teal, Juliet L Osborne and Robert J Paxton Publicador: Jennifer Teal, Juliet L Osborne and Robert J Paxton
Tipo: Conferência ou Objeto de Conferência
ENG
Relevância na Pesquisa
46.18%
The aim of the present work was to evaluate the total phenolic compounds, quantified and identified the phenolic and flavonoid compounds and also the antiodoxidant activity of the propolis, collected from two regions of Portugal (Trás-os-Montes and Beira-Baixa). The total phenolic content was determined by Folin-Ciocalteu method and identified by Thin Layer Chromatography (TLC) bi-dimensional. The antioxidant activity was evaluated by 1.1-diphenyl-2-picrylhydrazyl scavenging (DPPH) and reducing power assays. The results showed that Tras-os-Montes propolis (329mg/g eq. gallic acid) had a higher content in phenolic compounds of the methanolic extracts than Beira-Baixa propolis (151mg/g eq. gallic acid). The value of the antioxidant activity determined by the DPPH assay was EC50 = 6.22µg/mL and EC50 = 52.00 µg/mL for Trás-os-Montes and Beira-Baixa propolis, respectively. Similar trend was obtained by the reducing power assays (EC50 = 4µg/mL and EC50 = 39µg/mL for the same samples, respectively). Through analysis of the results we can see that the propolis sample of Trás-os-Montes was a highest antioxidant activity, probably due to the amount of total phenolic compounds. Our results suggest that the concentration of propolis of Tras-os-Montes necessary to obtain an antioxidant activity is very low...

Characterization of Brazilian lager and brown ale beers based on color, phenolic compounds, and antioxidant activity using chemometrics

GRANATO, Daniel; BRANCO, Gabriel Favalli; FARIA, Jose de Assis Fonseca; CRUZ, Adriano Gomes
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.4%
BACKGROUND: Epidemiological studies have shown that beer has positive effects on inhibiting atherosclerosis, decreasing the content of serum low-density lipoprotein cholesterol and triglycerides, by acting as in vivo free radical scavenger. In this research, the antioxidant activity of commercial Brazilian beers (n = 29) was determined by the oxygen radical absorbance capacity (ORAC) and 1,1 -diphenyl-2-picrylhydrazyl (DPPH(center dot)) assays and results were analyzed by chemometrics. RESULTS: The brown ale samples (n = 11) presented higher (P < 0.05) flavonoids (124.01 mg L(-1)), total phenolics (362.22 mg L(-1)), non-flavonoid phenolics (238.21 mg L(-1)), lightness (69.48), redness (35.75), yellowness (55.71), color intensity (66.86), hue angle (59.14), color saturation (0.9620), DPPH(center dot) values (30.96% inhibition), and ORAC values (3,659.36 mu mol Trolox equivalents L(-1)), compared to lager samples (n = 18). Brown ale beers presented higher antioxidant properties (P < 0.05) measured by ORAC (1.93 times higher) and DPPH (1.65 times higher) compared to lager beer. ORAC values correlated well with the content of flavonoids (r = 0.47; P = 0.01), total phenolic compounds (r = 0.44; P < 0.01) and DPPH (r = 0.67; P < 0.01). DPPH values also correlated well to the content of flavonoids (r = 0.69; P < 0.01)...

Brazilian flavonoid database: Application of quality evaluation system

MENEZES, Elizabete Wenzel de; SANTOS, Nelaine Cardoso; GIUNTINI, Eliana Bistriche; DAN, Milana C. T.; GENOVESE, Maria Ines; LAJOLO, Franco M.
Fonte: ACADEMIC PRESS INC ELSEVIER SCIENCE Publicador: ACADEMIC PRESS INC ELSEVIER SCIENCE
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.57%
Much information on flavonoid content of Brazilian foods has already been obtained; however, this information is spread in scientific publications and non-published data. The objectives of this work were to compile and evaluate the quality of national flavonoid data according to the United States Department of Agriculture`s Data Quality Evaluation System (USDA-DQES) with few modifications, for future dissemination in the TBCA-USP (Brazilian Food Composition Database). For the compilation, the most abundant compounds in the flavonoid subclasses were considered (flavonols, flavones, isoflavones, flavanones, flavan-3-ols, and anthocyanidins) and the analysis of the compounds by HPLC was adopted as criteria for data inclusion. The evaluation system considers five categories, and the maximum score assigned to each category is 20. For each data, a confidence code (CC) was attributed (A, B, C and D), indicating the quality and reliability of the information. Flavonoid data (773) present in 197 Brazilian foods were evaluated. The CC ""C"" (as average) was attributed to 99% of the data and ""B"" (above average) to 1%. The main categories assigned low average scores were: number of samples; sampling plan and analytical quality control (average scores 2...

A chemometric study on the analgesic activity of cannabinoid compounds using SDA, KNN and SIMCA methods

ARROIO, A.; LIMA, E. F.; HONORIO, K. M.; SILVA, A. B. F. da
Fonte: SPRINGER/PLENUM PUBLISHERS Publicador: SPRINGER/PLENUM PUBLISHERS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.2%
The supervised pattern recognition methods K-Nearest Neighbors (KNN), stepwise discriminant analysis (SDA), and soft independent modelling of class analogy (SIMCA) were employed in this work with the aim to investigate the relationship between the molecular structure of 27 cannabinoid compounds and their analgesic activity. Previous analyses using two unsupervised pattern recognition methods (PCA-principal component analysis and HCA-hierarchical cluster analysis) were performed and five descriptors were selected as the most relevants for the analgesic activity of the compounds studied: R (3) (charge density on substituent at position C(3)), Q (1) (charge on atom C(1)), A (surface area), log P (logarithm of the partition coefficient) and MR (molecular refractivity). The supervised pattern recognition methods (SDA, KNN, and SIMCA) were employed in order to construct a reliable model that can be able to predict the analgesic activity of new cannabinoid compounds and to validate our previous study. The results obtained using the SDA, KNN, and SIMCA methods agree perfectly with our previous model. Comparing the SDA, KNN, and SIMCA results with the PCA and HCA ones we could notice that all multivariate statistical methods classified the cannabinoid compounds studied in three groups exactly in the same way: active...

A chemometric study of the 5-HT1A receptor affinities presented by arylpiperazine compounds

WEBER, Karen C.; SILVA, Alberico B. F. da
Fonte: ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER Publicador: ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.18%
Arylpiperazine compounds are promising 5-HT1A receptor ligands that can contribute for accelerating the onset of therapeutic effect of selective serotonin reuptake inhibitors. In the present work, the chemometric methods HCA, PCA, KNN, SIMCA and PLS were employed in order to obtain SAR and QSAR models relating the structures of arylpiperazine compounds to their 5-HT1A receptor affinities. A training set of 52 compounds was used to construct the models and the best ones were obtained with nine topological descriptors. The classification and regression models were externally validated by means of predictions for a test set of 14 compounds and have presented good quality, as verified by the correctness of classifications, in the case of pattern recognition studies, and b, the high correlation coefficients (q(2) = 0.76, r(2) = 0.83) and small prediction errors for the PLS regression. Since the results are in good agreement with previous SAR studies, we can suggest that these findings can help in the search for 5-HT1A receptor ligands that are able to improve antidepressant treatment. (c) 2007 Elsevier Masson SAS. All rights reserved.

Isolamento e identificação de compostos com atividade antioxidante de uma nova variedade de própolis brasileira produzida por abelhas da espécie Apis mellifera; Isolation and identification of compounds with antioxidant activity in a novel variety of Brazilian propolis produced by bees from the species Apis mellifera

Oldoni, Tatiane Luiza Cadorin
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/09/2007 PT
Relevância na Pesquisa
46.23%
A própolis é conhecida por suas atividades biológicas, tais como antioxidante, antimicrobiana, antinflamatória, antiviral, entre outras. Sua composição varia entre regiões e existe grande diversidade química entre os diferentes tipos de própolis. Os principais constituintes da própolis são os compostos fenólicos, os quais são responsáveis por várias atividades biológicas, como a atividade antioxidante. Um novo tipo de própolis, nunca antes relatado na literatura, denominado própolis vermelha em decorrência de sua coloração intensa característica, foi coletado na região de mangue do Estado de Alagoas. Este trabalho teve como objetivo avaliar a composição química e fracionar e isolar compostos com atividade antioxidante da própolis vermelha brasileira. O extrato etanólico da própolis vermelha (EEP) foi primeiramente fracionado pela técnica de extração líquido-líquido, originando as frações hexânica (fr-Hex) e clorofórmica (fr- Clo). A fr-Clo apresentou alto rendimento e composição química complexa, sendo, então, recromatografada em coluna aberta de sílica-gel, gerando 15 subfrações. O EEP, frações e subfrações foram avaliados quanto à sua composição química e atividade antioxidante para seleção das frações destinadas ao isolamento bioguiado. O EEP também foi analisado pela técnica de cromatografia gasosa acoplada à espectrometria de massas (CG-EM)...

Atividade de enzimas do metabolismo de compostos secundários comprometidos com o enraizamento "in vitro" de Eucalyptus grandis HILL ex MAIDEN; Enzyme activity of metabolism of secondary compounds related to in vitro rooting of Eucalyptus grandis HILL ex MAIDEN

Machado, Isaac Stringueta
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/11/1993 PT
Relevância na Pesquisa
46.09%
O trabalho realizado constitui uma estratégia em Biotecnologia de Plantas para a investigação dos esquemas bioquímicos controladores da diferenciação celular no processo de enraizamento. Através da técnica da cultura de tecidos "in vitro" foram micropropagados clones de Eucalyptus grandis HILL ex MAIDEN (GO 250, GO 682 e GO 669) selecionadas no CEBTEC/USP. Em uma pesquisa preliminar foram estabelecidas e multiplicadas gemas, seguida de testes da composição de meios de cultura para elongação e enraizamento. Foram estudadas diversas possibilidades de balanceamento das substâncias reguladoras de crescimento - ácido indolilbutírico (AIB)/ benzilaminopurina (BAP). Os clones apresentaram comportamentos anatômico-fisiológicos (massa fresca e seca; teor protéico; taxas de multiplicação das brotações epicórmicas, elongação e enraizamento) diferenciados entre si. As frequências de enraizamento mostraram-se superiores às já observadas por outros autores. Foram estabelecidas, ainda, algumas alterações na composição dos meios de cultura empregados. Através de experimentos cinéticos foram determinados os padrões de indução e/ou inibição das enzimas fenilalanina amônia-liase (PAL) e glucose 6-fosfato-desidrogenase (G-6P-DH) importantes para a biossíntese de compostos flavonóides...

The use of classification methods for modeling the antioxidant activity of flavonoid compounds

Weber, Karen C.; Honorio, Kathia M.; Bruni, Aline T.; da Silva, Alberico B. F.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 915-920
ENG
Relevância na Pesquisa
66.42%
A study using two classification methods (SDA and SIMCA) was carried out in this work with the aim of investigating the relationship between the structure of flavonoid compounds and their free-radical-scavenging ability. In this work, we report the use of chemometric methods (SDA and SIMCA) able to select the most relevant variables (steric, electronic, and topological) responsible for this ability. The results obtained with the SDA and SIMCA methods agree perfectly with our previous model, in which we used other chemometric methods (PCA, HCA and KNN) and are also corroborated with experimental results from the literature. This is a strong indication of how reliable the selection of variables is.

A partial least squares regression study with antioxidant flavonoid compounds

Weber, Karen C.; Honorio, Kithia M.; Bruni, Aline T.; Andricopulo, Adriano D.; da Silva, Alberico B. F.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 307-313
ENG
Relevância na Pesquisa
66.61%
The quantitative structure-activity relationship of a set of 19 flavonoid compounds presenting antioxidant activity was studied by means of PLS (Partial Least Squares) regression. The optimization of the structures and calculation of electronic properties were done by using the semiempirical method AMI. A reliable model (r(2) = 0.806 and q(2) = 0.730) was obtained and from this model it was possible to consider some aspects of the structure of the flavonoid compounds studied that are related with their free radical scavenging ability. The quality of the PLS model obtained in this work indicates that it can be used in order to design new flavonoid compounds that present ability to scavenge free radicals.

Characterization of Brazilian lager and brown ale beers based on color, phenolic compounds, and antioxidant activity using chemometrics

GRANATO, Daniel; BRANCO, Gabriel Favalli; FARIA, Jose de Assis Fonseca; CRUZ, Adriano Gomes
Fonte: WILEY-BLACKWELL PUBLISHING, INC Publicador: WILEY-BLACKWELL PUBLISHING, INC
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.4%
BACKGROUND: Epidemiological studies have shown that beer has positive effects on inhibiting atherosclerosis, decreasing the content of serum low-density lipoprotein cholesterol and triglycerides, by acting as in vivo free radical scavenger. In this research, the antioxidant activity of commercial Brazilian beers (n = 29) was determined by the oxygen radical absorbance capacity (ORAC) and 1,1 -diphenyl-2-picrylhydrazyl (DPPH(center dot)) assays and results were analyzed by chemometrics. RESULTS: The brown ale samples (n = 11) presented higher (P < 0.05) flavonoids (124.01 mg L(-1)), total phenolics (362.22 mg L(-1)), non-flavonoid phenolics (238.21 mg L(-1)), lightness (69.48), redness (35.75), yellowness (55.71), color intensity (66.86), hue angle (59.14), color saturation (0.9620), DPPH(center dot) values (30.96% inhibition), and ORAC values (3,659.36 mu mol Trolox equivalents L(-1)), compared to lager samples (n = 18). Brown ale beers presented higher antioxidant properties (P < 0.05) measured by ORAC (1.93 times higher) and DPPH (1.65 times higher) compared to lager beer. ORAC values correlated well with the content of flavonoids (r = 0.47; P = 0.01), total phenolic compounds (r = 0.44; P < 0.01) and DPPH (r = 0.67; P < 0.01). DPPH values also correlated well to the content of flavonoids (r = 0.69; P < 0.01)...

Impact of malolactic fermentation on low molecular weight phenolic compounds

Cabrita, Maria João; Torres, Maria; Palma, Vera; Alves, Elisabete; Patão, Raquel; Costa Freitas, Ana Maria
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 373390 bytes; application/pdf
ENG
Relevância na Pesquisa
46.35%
A reversed phase liquid chromatography-DAD method is proposed for analysis of major non-flavonoid phenolic compounds in wines. The method employed a mixture of acetic acid, water and methanol as eluents and was used to evaluate the impact of malolactic fermentation in low molecular phenolic compounds. The wines analyzed underwent different treatments, like the addition of a pectolytic enzyme or lysozyme, and the way malolactic fermentation was carried out—spontaneously or with the inoculation of two different commercial lactic bacteria. The main result observed was the disappearance of hydroxycinnamoyltartaric acids and the increase of resultant free forms, regardless the way malolactic fermentation was carried out.

Metabolism of apigenin and related compounds in the rat. Metabolite formation in vivo and by the intestinal microflora in vitro

Griffiths, L. A.; Smith, G. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1972 EN
Relevância na Pesquisa
36.56%
1. The metabolism of a group of flavonoid compounds related in structure to apigenin (4′,5,7-trihydroxyflavone) and including apigenin, apiin, naringin, phlorrhizin, acacetin, kaempferol, robinin, chrysin, tectochrysin and 4′,7-dihydroxyflavone, was studied both in vivo after oral administration to the rat, and in vitro in cultures of micro-organisms derived from the intestine of the rat. 2. The rat intestinal microflora is capable of effecting degradation of flavonoid compounds to metabolites observed in the urine after oral administration of the specific flavonoid. 3. All compounds possessing free 5- and 7-hydroxyl groups in the A ring and a free 4′-hydroxyl group in the B ring gave rise to ring-fission products, which included 4′-hydroxyphenylacyl derivatives. 4. On anaerobic incubation in a thioglycollate medium, intestinal micro-organisms can effect flavonoid-ring fission, cleavage of glycosidic bonds and the reduction of double bonds in the side chains of certain metabolites. 5. Two flavonoids (chrysin and tectochrysin) undergo hydroxylation in the 4′-position in vivo but not during incubation with the intestinal microflora in vitro. 6. Observations on the metabolism of other compounds substituted in the 4′-position...

Structure-Based Design of Flavonoid Compounds As a New Class of Small-Molecule Inhibitors of the Anti-apoptotic Bcl-2 Proteinŝ

Tang, Guozhi; Ding, Ke; Nikolovska-Coleska, Zaneta; Yang, Chao-Yie; Qiu, Su; Shangary, Sanjeev; Wang, Renxiao; Guo, Jie; Gao, Wei; Meagher, Jennifer; Stuckey, Jeanne; Krajewski, Krzysztof; Jiang, Sheng; Roller, Peter P.; Wang, Shaomeng
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.25%
Structure-based strategy was employed to design flavonoid compounds to mimic the Bim BH3 peptide as a new class of inhibitors of the anti-apoptotic Bcl-2 proteins. The most potent compound, 4 (BI-33), binds to Bcl-2 and Mcl-1 with Ki values of 17 and 18 nM, respectively. Compound 4 inhibits cell growth in the MDA-MB-231 breast cancer cell line with an IC50 value of 110 nM and effectively induces apoptosis.

Flavonoid Compounds Identified in Alchemilla L. Species Collected in the North-Eastern Black Sea Region of Turkey

Kaya, Bülent; Menemen, Yusuf; Saltan, Fatma Zerrin
Fonte: African Networks on Ethnomedicines Publicador: African Networks on Ethnomedicines
Tipo: Artigo de Revista Científica
Publicado em 02/04/2012 EN
Relevância na Pesquisa
46.67%
This study identified flavonoid glycosides in species of the genus Alchemilla, A. procerrima, A. stricta, A. hirtipedicellata and A. sericata. A. procerrima is an endemic species for Turkey. After detailed investigation, flavonoid compounds of the species were identified for the first time. In this study, flavonoid compounds were determined by using two different chromatography techniques, TLC and HPLC. The following flavonoid compounds were identified from the Alchemilla species studied. They are as follows: orientin (luteolin-8-C-glucoside) Rf: 0,70, vitexin (apigenin-8-C-glucoside) Rf: 0,77 as flavone-C-glycoside, rutin (quercetin-3-O-rutinoside) Rf: 0,44, hyperoside (quercetin-3-O-galactoside) Rf: 0,65, isoquercetin (quercetin-3-O-glucopyranoside) Rf: 0,72, quercitrin (quercetin-3-O-rhamnoside) Rf: 0,84 as flavonol-O-glycoside. Three more folavonoids with Rf values of Rf1= 0,36, Rf2=0,54 and Rf3=0,68 were also identified for the first time in this study. Rutin (quercetin-3-O-rutinoside) and the flavonoid glycoside, shown as Rf2 were found in all species. Quercitrin and isoquercetin were determined in all analysed species but A. procerrima. Hyperoside was identified in all species except for A. stricta. Vitexin was determined only in A.stricta. Orientin was determined in A. procerrima and A. stricta...

Different Biosynthesis Patterns among Flavonoid 3-glycosides with Distinct Effects on Accumulation of Other Flavonoid Metabolites in Pears (Pyrus bretschneideri Rehd.)

Zhai, Rui; Liu, Xiao-Ting; Feng, Wen-Ting; Chen, Sha-Sha; Xu, Ling-Fei; Wang, Zhi-Gang; Zhang, Jiang-Li; Li, Peng-Min; Ma, Feng-Wang
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 17/03/2014 EN
Relevância na Pesquisa
36.74%
Flavonoid biosynthesis profile was clarified by fruit bagging and re-exposure treatments in the green Chinese pear ‘Zaosu’ (Pyrus bretschneideri Rehd.) and its red mutant ‘Red Zaosu’. Two distinct biosynthesis patterns of flavonoid 3-glycosides were found in ‘Zaosu’ pear. By comparison with ‘Red Zaosu’, the biosynthesis of flavonoid 3-galactosides and flavonoid 3-arabinosides were inhibited by bagging and these compounds only re-accumulated to a small degree in the fruit peel of ‘Zaosu’ after the bags were removed. In contrast, the biosynthesis of flavonoid 3-gluctosides and flavonoid 3-rutinosides was reduced by bagging and then increased when the fruits were re-exposed to sunlight. A combination of correlation, multicollinearity test and partial-correlation analyses among major flavonoid metabolites indicated that biosynthesis of each phenolic compound was independent in ‘Zaosu’ pear, except for the positive correlation between flavonoid 3-rutincosides and flavanols. In contrast with the green pear cultivar, almost all phenolic compounds in the red mutant had similar biosynthesis patterns except for arbutin. However, only the biosynthesis of flavonoid 3-galactosides was relatively independent and strongly affected the synthesis of the other phenolic compounds. Therefore...

Antioxidative Activities and Active Compounds of Extracts from Catalpa Plant Leaves

Xu, Hongyu; Hu, Gege; Dong, Juane; Wei, Qin; Shao, Hongbo; Lei, Ming
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.64%
In order to screen the Catalpa plant with high antioxidant activity and confirm the corresponding active fractions from Catalpa ovata G. Don, C. fargesii Bur., and C. bungei C. A. Mey., total flavonoid contents and antioxidant activities of the extracts/fractions of Catalpa plant leaves were determined. The determined total flavonoid content and antioxidant activity were used as assessment criteria. Those compounds with antioxidant activity were isolated with silica gel column chromatography and ODS column chromatography. Our results showed that the total flavonoid content in C. bungei C. A. Mey. (30.07 mg/g·DW) was the highest, followed by those in C. fargesii Bur. (25.55 mg/g·DW) and C. ovata G. Don (24.96 mg/g·DW). According to the determination results of total flavonoid content and antioxidant activity in 3 clones of leaves of C. bungei C. A. Mey., the total flavonoid content and antioxidant activity in crude extracts from C. bungei C. A. Mey. 6 (CA6) leaves were the highest. Moreover, the results showed that the total flavonoid content and antioxidant activities of ethyl acetate (EA) fraction in ethanol crude extracts in CA6 leaves were the highest, followed by n-butanol, petroleum ether (PE), and water fractions. Two flavonoid compounds with antioxidant activity were firstly isolated based on EA fraction. The two compounds were luteolin (1) and apigenin (2)...

The influence of viticultural treatments on the accumulation of flavonoid compounds in grapes and their contribution to wine quality.

Cordon, Nicole
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
Relevância na Pesquisa
46.64%
The grape flavonoids include anthocyanins, tannins and flavonols, all of which contribute to grape and wine quality by influencing the colour and mouthfeel of red wine. These compounds are synthesized in different parts of the berry and during different stages of berry development. In addition, environmental and viticultural factors such as light exposure can also alter the flavonoid composition of grapes. An understanding of how synthesis of these compounds is coordinated, their relationship to wine quality and the influence of bunch light exposure on the flavonoid composition of grapes, could be used to improve fruit quality by enhanced viticultural management. The first part of this study sought to investigate the relationship between the different products of the flavonoid biosynthetic pathway (anthocyanins, flavonols and tannins), from two climatic regions (warm and cool) and determine their role in grape and wine quality. In collaboration with a major winery, whole Shiraz grapes were sampled at the weighbridge from a range of different vineyards from two climatic regions; warm (Riverland) and cool (McLaren Vale) in 2003 and 2004. A total of 80 grape samples were collected in each season and processed (i.e. 100 berries, separated into skin...

Effects of Flavonoid Compounds on β-amyloid-peptide-induced Neuronal Death in Cultured Mouse Cortical Neurons

Choi, Seong-Min; Kim, Byeong C.; Cho, Yeun-Hee; Choi, Kang-Ho; Chang, Jane; Park, Man-Seok; Kim, Myeong-Kyu; Cho, Ki-Hyun; Kim, Jong-Keun
Fonte: Chonnam National University Medical School Publicador: Chonnam National University Medical School
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.65%
Excessive accumulation of β-amyloid peptide (Aβ) is one of the major mechanisms responsible for neuronal death in Alzheimer's disease. Flavonoids, primarily antioxidants, are a group of polyphenolic compounds synthesized in plant cells. The present study aimed to identify flavonoid compounds that could inhibit Aβ-induced neuronal death by examining the effects of various flavonoids on the neurotoxicity of Aβ fragment 25-35 (Aβ25-35) in mouse cortical cultures. Aβ25-35 induced concentration- and exposure-time-dependent neuronal death. Neuronal death induced by 20 µM Aβ25-35 was significantly inhibited by treatment with either Trolox or ascorbic acid. Among 10 flavonoid compounds tested [apigenin, baicalein, catechin, epicatechin, epigallocatechin gallate (EGCG), kaempferol, luteolin, myricetin, quercetin, and rutin], all except apigenin showed strong 1,1-diphenyl-2-pycrylhydrazyl (DPPH) scavenging activity under cell-free conditions. The flavonoid compounds except apigenin at a concentration of 30 µM also significantly inhibited neuronal death induced by 20 µM Aβ25-35 at the end of 24 hours of exposure. Epicatechin, EGCG, luteolin, and myricetin showed more potent and persistent neuroprotective action than did the other compounds. These results demonstrated that oxidative stress was involved in Aβ-induced neuronal death...

Microwave-assisted extraction of phenolic and flavonoid compounds from Eucalyptus camaldulensis Dehn leaves as compared with ultrasound-assisted extraction

Gharekhani,M.; Ghorbani,M.; Rasoulnejad,N.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2012 EN
Relevância na Pesquisa
56.58%
In the present study, a microwave-assisted extraction (MAE) technique has been developed for extraction of phenolic and flavonoid compounds from eucalyptus leaves. Various experimental conditions, such as solvent type, ethanol concentration, MAE time, liquid/solid ratio and pre-leaching time before MAE were examined to optimize the extraction. Among the solvents tested, 50% aqueous ethanol extracted the highest phenolic and flavonoid contents from eucalyptus leaves. The extraction of phenolic and flavonoid compounds with MAE for 5 min was equivalent with ultrasound-assisted extraction (UAE) (60 min) and traditional extraction (24 h) methods. Time of extraction at room temperature and UAE was about 288 and 12 times higher than the needed with MAE, respectively. Due to the considerable saving in time, MAE was more effective than the traditional and UAE methods.

Vasodilator profile of flavonoid and phenylbutanoid compounds isolated from Croton schiedeanus Schlecht

Correa-Hernández,Sofía Ximena; Ibánez,Pilar Puebla; Carrón de la Calle,Rosalía; Martín-Calvo,María Luisa; San Román del Barrio,Luis; Guerrero Pabón,Mario Francisco
Fonte: Revista de la Facultad de Medicina Publicador: Revista de la Facultad de Medicina
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2008 EN
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36.54%
Background. Croton schiedeanus Schlecht (Euphorbiaceae), specie is used in Colombian folk medicine in hypertension treatment. Objective. To assess the vasorelaxant effect of the flavonoid compounds: 3-O-methyl-quercetin, 3,7-di-O-methylquercetin, and 3,3',4',7-tetra-O-methylquercetin, and the phenylbutanoids compounds: (2S)-7,9-dimethoxyrhododendrol, (2S)-2-acetoxy-7,9-dimetho-xyrho-dodendrol, (2S)-2,8-diacetatoxy-7,9-dimethoxyrho-dodendrol in isolated aortic rings of Wistar rats. Materials and methods. These compounds were evaluated in phenylephrine (PE, 1 µM) and KCl (80 mM) precontracted aortic rings. In order to examine possible interactions related with: endothelium, nitric oxide (NO), guanylyl ciclasa, prostanoid or ATP dependent potassium (K+ATP) channels, the compounds with greater relaxant effect: 3-O-methylquercetin, and 3,7-di-O-methylquer-cetin, were assessed in phenylephrine precontracted rings in presence or absence of: endothelium, L-NAME (G -nitro-L-Arginine-Methyl Ester, 100 µM), ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, 1 µM), sodium meclofenamate (10 µM) or glibenclamide (1 µM). Results. Whereas phenylbutanoid compounds did not shown significant relaxant properties, 3-O-methylquercetin and 3,7-di-O-methyl-quercetin displayed important vasodilator responses with IC50 of 2.5 and 4.9 µM against phenylephrine respectively. ODQ and L-NAME effectively displaced to the right the dose-response curves of these compounds...