Studies on cytotoxic pregnane sapogenins from Cynanchum wilfordii

To investigate their cytotoxicity, seventeen C21-steroidal pregnane sapogenins 1-17 were isolated from the hydrolytic extracts of the roots of Cynanchum wilfordii. Among them, sapogenins 1-7 are new compounds, whose structures were determined by extensive analysis of spectroscopic data and X-ray crystallographic analysis. Especially, sapogenins with salicyl or vanilloyl group, and a new aberrant pregnane skeleton with ether linkage between C-12 and C-20 were found for the first time. Compound 1 revealed significant cytotoxicities on HL-60 (IC50 6.72 μM) and MCF-7 (IC50 2.89 μM), and compounds 14 and 15 also revealed strong inhibitory activities against K-562 (IC50 6.72 μM) or MCF-7 (IC50 2.49 μM), respectively.

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