Protective effects of resveratrol against oxidative/nitrative modifications of plasma proteins and lipids exposed to peroxynitrite

The protective effects of resveratrol (3, 4', 5-trihydroxystilbene; present naturally in different plants) against the oxidative/nitrative damage of human plasma proteins induced by peroxynitrite (ONOO-) were studied and compared with those of deferoxamine (DFO; a natural siderophore isolated from Streptomyces pilosus), which is a typical and well-known antioxidant. We also studied the effect of ONOO- on plasma lipid peroxidation and the role of tested antioxidants in this process. ONOO- at the used concentrations (0.01-1 mM) showed toxicity to human plasma components. Exposure of plasma to ONOO- (0.1 mM) resulted in an increase of the level of carbonyl groups and nitrotyrosine residues in plasma proteins (approximately 4-fold and 76-fold, respectively) and in a distinct augmentation of lipid peroxidation (approximately 2-fold). In the presence of 0.1-mM resveratrol, a distinct decrease of carbonyl group formation and tyrosine nitration in plasma proteins caused by 0.1-mM ONOO- was observed (by approximately 70% and 65%, respectively). Addition of 0.1-mM DFO to plasma also distinctly reduced the level of carbonyl groups and nitrotyrosines caused by 0.1-mM ONOO- (by approximately 50% and 60%, respectively). Moreover, these antioxidants also inhibited plasma lipid peroxidation induced by ONOO- (0.1 mM). The obtained results indicate that in vitro resveratrol, like well-known antioxidant DFO, has inhibitory effects on ONOO- -mediated oxidation of proteins and lipids in human plasma.