Anticoagulant activities of oleanolic acid via inhibition of tissue factor expressions

Oleanolic acid (OA), a triterpenoid known for its anti-inflammatoryand anti-cancer properties, is commonly present in severalmedicinal plants but its anticoagulant activities have not beenstudied. Here, the anticoagulant properties of OA were determinedby monitoring activated partial thromboplastin time (aPTT),prothrombin time (PT), fibrin polymerization as well as cell-basedthrombin and activated factor X (FXa) generation activities. Datashowed OA prolonged aPTT and PT significantly and inhibitedthrombin catalyzed fibrin polymerization. In addition, OA inhibitedthe activities of thrombin and FXa and inhibited the generationof thrombin or FXa in human endothelial cells. OA also inhibitedTNF-α-induced tissue factor expression on human endothelialcells. In accordance with these anticoagulant activities, OAshowed an anticoagulant effect in vivo. These results indicate thatOA possesses antithrombotic activities and suggest that daily consumptionof a herb containing OA may be preventing thrombosisin pathological states.