Hepatoprotective steroids from roots of Cynanchum otophyllum.

Seven undescribed C21 steroids, namely cynanchin A-G, together with thirteen known analogues, were isolated from the roots of cynanchum otophyllum. Their structures were elucidated by 1D, 2D NMR and MS spectra, as well as chemical methods. Meanwhile, all of isolates were tested for their anti-hepatic fibrosis activity. Among them, compounds 4-6, 10-12 and 14-17 showed moderate or significant inhibitory effects for the proliferation of hepatic stellate cells (HSCs) induced by transforming growth factor-β1 (TGF-β1) in vitro.