Antioxidant capacity of polyphenols and argentine red wines.

VALDEZ LB; ZAOBORNYJ T; ALVAREZ S; BOVERIS A

Bento Conçalves, Rio Grande do Sul, Brasil.

Congreso; Vinho e Saúde - Vinho como alimento natural.; 2005

Introduction: Wine is an important component in Mediterranean dietary traditions and its moderate consumption can reduce mortality from coronary heart diseases. The chemical composition of wine is profoundly influenced by enological techniques, the grape cultivar, and climatic factors. Red wines have antioxidant properties due to the presence of polyphenols and hydroxycinnamates. It has been reported that these compounds are efficient scavengers of peroxynitrite (ONOO-) and arterial vasodilators. Methods and Results: The antioxidant capacity of the polyphenols (+)-catechin, (-)-epicatechin and myricetin, and different types of red wines was assessed by three assays. (a) NADH oxidation by ONOO-: the ONOO- scavenging activity was higher for myricetin (IC50=35 mM) than for (+)-catechin (IC50=275 mM) and (-)-epicatechin (IC50=313 mM). (b) Peroxynitrite initiated chemiluminescence in rat liver homogenate: (-)-epicatechin (IC50=7.0 mM) and (+)-catechin (IC50=13 mM) were more potent than myricetin (IC50=20 mM) in inhibiting the chemiluminescence signal. (c) Lucigenin chemiluminescence in aortic rings: (-)-epicatechin (IC50=15 mM) and (+)-catechin (IC50=18 mM) showed higher antioxidant capacity than myricetin (IC50=32 mM).  All the assayed argentine red wines were able to scavenge the oxidants and free radical species that generate the signal in each assay. The antioxidant capacity was not clearly different in a single grape varietal or vineyard region. Compared with red wines from other countries, Argentine red wines exhibited excellent antioxidant properties. Conclusion: It is concluded that the use of sensitive biological systems (as the aortic rings chemiluminescence) provide important information in addition to the results from chemical (NADH oxidation by peroxynitrite) and biochemical (homogenate chemiluminescence) assays and advances in the physiological role of polyphenols.