The pregnane glycoside marsdekoiside A from Marsdenia Koi - Yuan,J.L.; Lu,Z.Z.; Chen,G.X.; Ding,W.P.; Zhou,B.N.; Erdelmeier,C.AJ.; Hamburger ,M.O.; Fong,H.HS.; Cordell,G.A. (Phytochemistry, 1992)