Antithrombotic and antiplatelet activities of pelargonidin in vivo and in vitro.

Pelargonidin is a well-known red pigment found in plants, and has been reported as having important biological activities that are potentially beneficial for human health. However, the possible roles of pelargonidin as an anticoagulant and the underlying mechanism have not yet been elucidated. We tested the effect of pelargonidin and its glucoside-conjugated form, pelargonidin-3-glucoside, on the clotting times, such as activated partial thromboplastin time (aPTT) and prothrombin time (PT), and the activities and productions of thrombin and activated factor X (FXa). Furthermore, the effects of pelargonidin on the fibrin polymerization, platelet aggregation, and the ratio of plasminogen activator inhibitor-1 (PAI-1) to tissue plasminogen activator were determined. Pelargonidin, but not pelargonidin-3-glucoside, prolonged the aPTT and PT, and inhibited the activity and production of thrombin and FXa in human umbilical vein endothelial cells. Furthermore, pelargonidin inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation and elicited anticoagulant effects in mice. In addition, pelargonidin significantly reduced PAI-1 to t-PA ratio. Collectively, these results indicate that the anthocyanin pelargonidin possesses antithrombotic activity, and can be beneficial in preventing thrombus formation, thus improving blood circulation.