Antitumor activity of C-21 steroidal glycosides from Cynanchum auriculatum Royle ex Wight

The antitumor activities of six C-21 steroidal glycosides isolated from the root tuber of Cynanchum auriculatum Royle ex Wight were performed according to a microculture tetrazolium (MTT) method on human tumor cell lines SMMC-7721, MCF-7 and Hela. Of these compounds, caudatin-2,6-dideoxy-3-O-methy-β-d-cymaropyranoside and caudatin were found to be of the highest effects against human tumor cell line SMMC–7721 with IC50 values of 13.49 and 24.95 μM, respectively. Then the in vivo assay further showed that caudatin-2,6-dideoxy-3-O-methy-β-d-cymaropyranoside and caudatin significantly inhibited the growth of transplantable H22 tumors in mice.