The green tea extract epigallocatechin gallate inhibits human platelet function but not plasma coagulation

The green tea extract epigallocatechin gallate (EGCG) has been demonstrated to exert various biological activities including anti-inflammatory, anti-oxidative, and anti-carcinogenic effects, as well as cardiovascular benefits. A limited number of studies have reported antiplatelet effects of EGCG. Furthermore, few studies have investigated its effect on the blood coagulation pathways. The aim of this study was to investigate the effects of EGCG on platelet aggregation and activation and plasma coagulation times. EGCG at 50 or 100 µM significantly inhibited turbidimetric ADP stimulated platelet aggregation. Furthermore, the same concentrations significantly inhibited ADP induced platelet surface expression of P-selectin as measured by CD62P fluorescence. Coagulation studies were performed using platelet poor plasma in the presence of EGCG. At the concentrations tested, ECGC did not alter the coagulation times of both prothrombin time and activated partial thromboplastin time. These results demonstrate that EGCG has an antiplatelet action without affecting the plasma coagulation cascade, suggesting that this green tea component could be used as a preventative strategy to lower the risk of thrombotic complications.