RESUMO
The antioxidant capacity of different types of red and white wines was assessed by different assays. Two assays were used to evaluate the antioxidant capacity in aqueous phase: (1) inhibition of the generation of 2,2'-azinodi(3-etilbencenotiazolin-6-sulfonate) (ABTS)-derived radical; and (2) protection of vitamin E in human plasma. The results indicated that red wines were not all equally effective, and a comparison could be made among different types. The ABTS assay showed that Cabernet Sauvignon wines had the highest antioxidant capacity followed by Malbec wines. Red wines showed a protective capacity of 70-90% in preventing SH-groups oxidation, and, in addition, they were also effective in preventing the oxidative damage in lipid domains (30-97% protection to liposomes, 20-70% to vitamin E). The antioxidant capacity of the white wines was significantly lower, as evaluated by all the assays. Significant correlations were found for phenolics and catechin content with the antioxidant capacity of the studied wines.
Assuntos
Antioxidantes/farmacologia , Vinho , Animais , Argentina , Benzotiazóis , Cátions/antagonistas & inibidores , Bovinos , Radicais Livres/antagonistas & inibidores , Humanos , Lipossomos/metabolismo , Oxirredução/efeitos dos fármacos , Compostos de Sulfidrila/metabolismo , Ácidos Sulfônicos/metabolismo , Vitamina E/sangueRESUMO
The antioxidant activity of catechin monomers and procyanidin (dimers to hexamers) fractions purified from cocoa was studied in two in vitro systems: liposomes and human LDL. Liposome oxidation (evaluated as formation of 2-thiobarbituric acid reactive substances) was initiated with 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH), 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN), iron/ascorbate, or UV-C; LDL oxidation (evaluated as formation of conjugated dienes) was initiated with Cu(2+) or AAPH. Catechin monomers and procyanidin fractions inhibited both liposome and LDL oxidation. Monomers, dimers, and trimers fractions were the most effective antioxidants when liposome oxidation was initiated in the aqueous phase. When oxidation was initiated in the lipid domains, higher molecular weight procyanidins were the most effective. All fractions significantly inhibited Cu-mediated LDL oxidation; no significant effect of procyanidin molecular weight was observed. The hexamer fraction was the least effective with respect to preventing AAPH initiated LDL oxidation. Results reported herein give further evidence on the influence of the oligomer chain length on the antioxidant protection by procyanidins.