Thrombosis is the formation of blood clots both in arteries or veins, which can be caused by platelet aggregation. It is the risk factor of cardiovascular disease. Thrombosis may cause venous thromboembolism (VTE). 1,2 The most serious complication of VTE is pulmonary embolism (PE), which occurs in more than a one-third of VTE patients and contributing to 12% of patient deaths. 3-5 Aspirin is one of the drugs which can inhibit platelet aggregation. This drug inhibits cyclooxygenase (COX) enzyme in cyclooxygenase pathway thus preventing thrombus formation. 6 Kaempferia galanga L. and Curcuma xanthorriza Roxb. (family: Zingiberaceae) have been reported to exhibit antithrombotic activity in vitro. 7,8 Cinnamaldehyde and curcumin have been identified as the major bioactive compounds in K. galanga and C. xanthorrhiza, respectively. These compounds have been reported to be able to inhibit platelet aggregation induced by collagen, arachidonic acid, and adenosine diphosphate (ADP) which reduced the formation of thromboxane A 2 (TxA 2) in cyclooxygenase pathway. 9-10 Cinnamaldehyde had shown to inhibit collagen-and thrombin-induced aggregation of rat platelets in vitro in a Antithrombotic Effect of Kaempferia galanga L. and Curcuma xanthorrhiza Roxb. on Collagen-epinephrine Induced Thromboembolism in Mice ABSTRACT Objective: Kaempferia galanga L. and Curcuma xanthorrhiza Roxb. have been proven to possess antiplatelet activity in vitro. The aim of this study is to investigate the antithrombotic effect of the rhizome extracts of Kaempferia galanga L. and Curcuma xanthorrhiza Roxb in a mouse thrombotic model. Methods: The ethanol extracts of K. galanga and C. xanthorrhiza were orally administered with three different doses (7, 14 and 28 mg/20 g BW) in two experimental mouse models. Bleeding time prolongation was observed on mice tail that had been cut and the survival rate of mice was observed after thromboembolism induction by collagenepinephrine. These two experiments were observed after 7 days extracts pre-treatment and compared to the positive control, aspirin. Results: A potent effect of K. galanga and C. xanthorrhiza extracts were demonstrated through significant bleeding time prolongation compared to control group. C. xanthorrhiza extract exhibited better activity than K. galanga extract. Moreover, both K. galanga and C. xanthorrhiza extracts significantly protected mice from thromboembolic death, where the protective effect of C. xanthorrhiza extract was stronger than K. galanga extract in a dose-dependent manner. Conclusion: K. galanga and C. xanthorrhiza extracts have a potential to be developed as antithrombotic agents against platelet thromboembolism.

Objective: This study aimed to investigate the antithrombotic activity of Tamarindus indica L. extract (TIE) in mouse models (in vivo).Methods: TIE was orally administered to mice at three different doses for 7 days. TIE-treated mice were used in two experiments of antithromboticactivity: An examination of bleeding time following tail cutting and an examination of survival rate after collagen-epinephrine-inducedthromboembolism. The TIE groups were observed after 7 days of treatment and compared to an aspirin-treated group and a control group.Results: Treatment with TIE led to a significant increase in bleeding time compared with that in the control group. TIE treatment also protected micefrom thromboembolic death, significantly increasing survival rates in a dose-dependent manner.Conclusion: TIE has the potential as an antithrombotic agent against platelet thromboembolism.