Anti-thrombotic effect of proanthocyanidin, a purified ingredient of grape seed

Introduction: Moderate and regular consumption of wine reduces the risk of acute coronary thrombotic events. The mechanism of the anti-thrombotic effect of wine is not clear. Extract or purified ingredients of grapes have not yet been studied for anti-thrombotic effect. Materials and methods: Anti-thrombotic effect of proanthocyanidin, a highly purified ingredient of grape seed, was assessed by a shear-induced thrombosis test in vitro and by a laser-induced thrombosis test in the mouse carotid artery, in vivo. Results and conclusions: Intravenously (20 mg/kg body weight, BW) or orally (2×200 mg/kg BW) administered proanthocyanidin significantly inhibited the laser-irradiation induced thrombus formation in the carotid artery (both P=0.01). Subsequent to oral administration of proanthocyanidin, in vitro platelet reactivity to shear stress has been inhibited. The latter suggests that the in vivo anti-thrombotic effect of proanthocyanidin may be due to a direct inhibitory effect on platelets.