STUDIES ON THE CYTOTOXIC CONSTITUENTS OF CYNANCHUM AURICULATUM ROYLE EX WIGHT

AIM To isolate and elucidate the chemical structures of two C 21 steroidal glycosides possessing cytotoxic activity from the root of Cynanchum auriculatum Royle ex Wight (Asclepiadaceae). METHODS The glycosides were isolated and purified by column chromatography on silica gel and HPLC. The molecular structures were determined on the basis of chemical evidence and extensive spectral analysis(UV, IR, 1HNMR, 13 CNMR, DEPT, HR FAB MS, FAB MS, HMQC and HMBC). RESULTS Two C 21 steroidal glycosides, named cynanauriculosides A and B, were obtained and their structures were elucidated as caudatin 3 O β D glucopyranosyl (1→4) β D cymaropynanosyl (1→4) β D oleandropyranosyl (1→4) β D cymaropynanoside and caudatin 3 O β D glucopyranosyl (1→4) β D oleandropyranosyl (1→4) β D digitoxopyranosyl (1→4) β D cymaropynanoside respectively. CONCLUSION Cynanauriculosides A and B are new compounds.