Antiplatelet effects of Spatholobus suberectus via inhibition of the glycoprotein IIb/IIIa receptor

Ethnopharmacological relevanceThe vine stem of Spatholobus suberectus is a widely used blood-activating and stasis-dispelling medicine for the treatment of diseases related to blood stasis syndrome in traditional medicine in Korea, Japan, and China.Aim of the studyTo demonstrate the clinical effects of Spatholobus suberectus against blood stasis syndromes using in vitro and in vivo platelet aggregation studies and to investigate its exact mechanisms.Materials and methodsWe extracted vine stems of Spatholobus suberectus, using 95% EtOH (SSE) and investigated its antiplatelet activity on platelet aggregation induced by collagen and ADP in human platelet-rich plasma (PRP). For the mechanism study, a glycoprotein IIb/IIIa (GP IIb/IIIa) assay using flow cytometric analysis and a thromboxane A2 (TXA2) assay were performed. In addition, we investigated the effects of SSE in a thromboembolic mouse model.ResultsSSE significantly inhibited ADP- and collagen-induced platelet aggregation in human PRP concentration-dependently without affecting plasma clotting time. It also significantly inhibited fibrinogen binding to the GP IIb/IIIa receptor and partly inhibited the formation of TXA2. In the in vivo study, oral administration of SSE dose-dependently suppressed the death of thromboembolism model mice induced by intravenous injection of collagen plus epinephrine.ConclusionsSSE showed antiplatelet activity without anticoagulant effects mainly through the inhibition of fibrinogen binding to the GP IIb/IIIa receptor. Our current results support the clinical usage of SSE in the East Asian region treating atherothrombotic diseases and may represent a new natural source to develop antiplatelet agents.

196