Resveratrol protects against peroxynitrite-induced thiol oxidation in blood platelets.

The peroxynitrite anion (ONOO-) is a reactive species produced in the reaction between the superoxide anion (O2*-) and nitric oxide (*NO). ONOO- is involved in several pathological conditions such as inflammation, arteriosclerosis, and neurodegenerative and cardiovascular disorders. Our earlier results showed that ONOO- inhibits different steps of blood platelet activation and causes the depletion of platelet thiols. In this study, we investigated the effects of resveratrol (3, 4', 5-trihydroxystilbene) and other antioxidants (uric acid and deferoxamine (DFO)) on the level of low molecular thiols such as glutathione, cysteine and cysteinylglycine (in reduced and oxidized form) in blood platelets treated with ONOO-. Our results showed that ONOO- (100 microM, 2 min) induces changes in these thiols (measured by HPLC method); these changes are diminished in the presence of resveratrol. Preincubation of human platelets with resveratrol at a concentration of 100 microM (30 min) has a protective effect against the oxidation of platelet thiols induced by ONOO- or its intermediate. The other tested antioxidants also have a protectory action. In conclusion, we suggest that the resveratrol present in the human diet may partially protect -SH groups from oxidation and may be responsible for redox regulation and control in platelets.