Cyclopia subternata is a medicinal plant commonly used in
traditional medicine to relieve
pain in physiological processes. However, there are limited modern data on its pharmacological effects and active components relating to its traditional use. Here, the
anticoagulant and antiplatelet activities of
vicenin-2 (VCN), an active compound in C. subternata, were determined. The
anticoagulant activities were investigated by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of
thrombin and
activated factor X (FXa). The effects of VCN on the expression of
plasminogen activator inhibitor type 1 (PAI-1) and
tissue-type plasminogen activator (t-PA) were evaluated in
tumor necrosis factor (TNF)-α-activated human umbilical vein endothelial cells (HUVECs). Treatment with VCN resulted in prolonged aPTT and PT and inhibition of the activities of
thrombin and FXa, as well as inhibited production of
thrombin and FXa in HUVECs. In addition, VCN inhibited
thrombin-catalyzed
fibrin polymerization and platelet aggregation. VCN also elicited
anticoagulant effects in mice. In addition, treatment with VCN resulted in significant reduction of the
PAI-1 to t-PA ratio. Collectively, VCN possesses antithrombotic activities and offers a basis for development of a novel
anticoagulant.