Blood anticoagulation and antiplatelet activity of green tea (-)-epigallocatechin (EGC) in mice.

EGC was prepared from green tea polyphenols through column chromatography of a polyamide (3.6 × 40 cm). Three dosages of EGC (0.25, 0.5, 1.0 g kg(-1) d(-1)) were ingested respectively by ICR mice via gavage. Compared with the control group, group EGC0.5 (dosage, 0. 5 g kg(-1) d(-1)) and group EGC1.0 (dosage, 1.0 g kg(-1) d(-1)) presented significant inhibition on platelet aggregation in mice accompanied by 18.4 and 25.6% of inhibition ratio, respectively. The bleeding times (BT) of mice in group EGC0.5 and group EGC1.0 were significantly prolonged (P < 0.01) as well as blood clotting time (BCT) in group EGC1.0 (P < 0.05). All three dosages of EGC prolonged activated partial thromboplastin time (APTT) significantly (P < 0.01), but had no prominent effect on prothrombin time (PT) and fibrinogen level which indicated that the anticoagulation of EGC could not be attributed to the level decrease of coagulation factor such as fibrinogen. The results demonstrated that EGC had prominent antiplatelet activity and blood anticoagulation in a dose-dependent manner.