8,14-Secopregnane glycosides from the aerial parts of Asclepias tuberosa.

Twenty pregnane glycosides, tuberoside A(1)-L(5), were isolated from the diethyl ether-soluble fraction of the MeOH extract from the aerial parts of Asclepias tuberosa (Asclepiadaceae). The pregnane glycosides were composed of 8,12;8,20-diepoxy-8,14-secopregnane as aglycon, and D-cymarose, D-oleandrose, D-digitoxose and/or D-glucose as the component sugars. Their structures were established using NMR spectroscopic analysis and chemical methodologies.