RESUMO
Grape juices are an important source of food antioxidants. Unfortunately, there is little data about the mineral composition and the antioxidant, mutagenic and antimutagenic activities of grape juice in eukaryote cells. We evaluated the mineral contents (Mg, Ca, Mn, Fe, Cu, Zn, Si, S, Cl) of grape juices, the antioxidant, mutagenic and/or antimutagenic activities of the juices in the yeast Saccharomyces cerevisiae, and looked for a possible association between mineral content and antioxidant, mutagenic and/or antimutagenic activities of juice samples. Eight commercial grape juices, four purple (Bordo variety) and four white (Niagara variety), were evaluated. Most of the minerals were in similar concentrations in purple and white grape juices, except for calcium and copper; purple grapes had more calcium content and white grapes had more copper content. All grape juices had important antioxidant and antimutagenic activities in S. cerevisiae and prevented the oxidative damage provoked by hydrogen peroxide (P < 0.05). Positive correlations (P < 0.05) were observed between antioxidant and antimutagenic activities and mineral content. In this context, we concluded that the grape juices, white and purple, are an important mineral source, and these contents explain, in part, the important antioxidant and antimutagenic activities.
Assuntos
Antimutagênicos/farmacologia , Antioxidantes/farmacologia , Bebidas/análise , Minerais/análise , Vitis/química , Alelos , Cobre/análise , Mutação da Fase de Leitura/genética , Peróxido de Hidrogênio/farmacologia , Viabilidade Microbiana , Fenóis/análise , Mutação Puntual/genética , Saccharomyces cerevisiae/citologia , Zinco/análiseRESUMO
In some countries, leaves of Vitis vinifera grapes have been used for food and for treating many medical disorders. However, there are no studies on the leaves of Vitis labrusca, the main species used for wine and juice production in South America. In this work, the phenolic compounds and antioxidant activity of organic and conventional grape leaves extracts prepared from V. labrusca (var. Bordo) in brain tissues (in vitro model) have been evaluated. Both organic and conventional grape leaves extracts have similar total phenolic content, however, different patterns were observed for the main phenolic compounds of both kinds of leaves. The organic leaves extract showed about 10 times more resveratrol than the conventional one. Both extracts were able to reduce the lipid and protein damages induced by hydrogen peroxide in the brain of rats. This effect was accompanied by the reversion of the hydrogen peroxide-induced alterations in the superoxide dismutase and catalase activities. Negative correlations between lipid and protein damages and the levels of polyphenols were found, suggesting that these compounds contribute directly to the protective effect observed.
Assuntos
Antioxidantes , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Peróxidos/toxicidade , Fenóis/química , Fenóis/farmacologia , Vitis/química , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Cerebelo/patologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Estresse Oxidativo/efeitos dos fármacos , Folhas de Planta/química , Ratos , Ratos Wistar , Resveratrol , Estilbenos/análise , Estilbenos/química , Estilbenos/farmacologia , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismoRESUMO
Although the beneficial effects of moderate wine intake are well-known, data on antioxidant capacity of grape juices are scarce and controversial. The purpose of this study was to quantify total polyphenols, anthocyanins, resveratrol, catechin, epicatechin, procyanidins, and ascorbic acid contents in grape juices, and to assess their possible antioxidant activity. Eight Vitis labrusca juices--white or purple, from organically- or conventionally-grown grapes, and obtained in pilot or commercial scale--were used. Organic grape juices showed statistically different (p<0.05) higher values of total polyphenols and resveratrol as compared conventional grape juices. Purple juices presented higher total polyphenol content and in vitro antioxidant activity as compared to white juices, and this activity was positively correlated (r=0.680; p<0.01) with total polyphenol content. These results indicate that white and purple grape juices can be used as antioxidants and nutritional sources.