(+)-Catechin inhibits platelet hyperactivity induced by an acute iron load in vivo.

Reactive oxygen species and platelets are thought to be involved in the pathogenesis of cardiovascular disease. Epidemiological data have indicated that high consumption of fruits and vegetables is associated with a lower incidence of vascular events. Polyphenols were proposed to provide such a protection. In the present study performed in rats, we investigated the influence of (+)-catechin (Cat), a polyphenol identified in tea, cocoa, and red wine, on an acute iron load-induced model of platelet hyperactivity. We found that platelet function was significantly enhanced in iron-loaded rats. These changes were associated with impairment of the antioxidative defense including ex vivo free radical-induced hemolysis. Pretreatment with Cat (10 mg/kg, ip, 4 d) normalized biomarkers of antioxidative status and platelet hyperactivity. The benefits of Cat treatment were only observed in iron-loaded animals and not in control animals. In light of the known antioxidant properties of Cat (or its metabolites), we suggest that oxidative injury-induced modification of platelet calcium homeostasis may have explained the iron load-induced platelet hyperactivity. The protective effect of Cat appears to work probably through normalization of the antioxidative status.