Consumption of Green Tea Extract Tablets Improved Anticoagulant Proteins and Reduced Platelet Aggregation in Transfusion-Dependent β-Thalassemia Patients

Abstract

Hypercoagulability and increased platelet activation have been associated with iron-overloaded β−thalassemia patients resulting in thrombosis. Iron chelators, antiplatelet and antithrombosis drugs are required to alleviate these complications. Epigallocatechin−3−gallate (EGCG)−rich green tea extract (GTE) is known to exert iron-chelating and antithrombotic activities. This study aimed to assess the effects of GTE tablet consumption on coagulation, platelet function and iron overload in transfusion-dependent β-thalassemia (TDT) patients. Each day, the subjects consumed a placebo, a single GTE tablet (50 mg EGCG equivalent) or GTE tablets (2x 50 mg EGCG equivalent) over a period of two months. Blood was then collected for analyses of platelet numbers, coagulation, platelet aggregation and iron parameters. Accordingly, GTE tablets significantly reduced the aggregation of platelets that had been induced ex vivo by ADP or collagen. The tablets also increased plasma protein C and protein S activities, as well as free protein S concentration levels depending upon the time course but not the GTE dosage. Surprisingly, plasma ferritin levels were decreased in both GTE tablet groups in a time-dependent manner, for which a significant difference was observed in the second month. In conclusion, EGCG−abundant GTE improved platelet aggregation and hypercoagulability in TDT patients by increasing the antithrombotic activity of protein C and protein S. Thus, GTE can be an adjuvant to reduce the risk of thrombosis associated with iron overload.