Inhibitory Actions of Steppogenin on Platelet Activity Through Regulation of Glycoprotein IIb/IIIa and Ca 2+ Mobilization

 The extract of Cudrania tricuspidata is used in ethnomedicine throughout Eastern Asia in China, Korea and Japan. In Korean traditional medicine, Cudrania tricuspidata has been used to treat eczema, mumps, tuberculosis, contusions, insom-nia and acute arthritis. In addition, it has been reported that root extract of Cudrania tricuspidata has anti-platelet effects. There-fore, we investigated which compound in Cudrania tricuspidata has inhibitory effect on platelet aggregation. In this study, we tried to explain the inhibitory mechanism of steppogenin from Cudrania tricuspidata on human platelet aggregation. Collagen-induced human platelet aggregation and [Ca 2+ ] i mobilization were dose-dependently inhibited by steppogenin and we deter-mined the inhibition by steppogenin is due to the down regulation of extracellular-signal-regulated kinase(ERK) and inositol-1,4,5-triphosphate receptor type I(IP 3 RI) phosphorylation. In addition, steppogenin inhibited collagen-induced fibronectin adhesion to  IIb/  3 and thromboxane A 2 generation. Thus, in the present study, steppogenin showed an inhibitory effect on human platelet aggregation, suggesting its potential use for preventing