Two new pregnane alkaloids from Sieb. et Zucc. and their cytotoxic activities.

Pactermines E and F ( and ), two new pregnane alkaloids were isolated from the whole plant of Sieb. et Zucc. Their structures were determined by physicochemical properties and spectroscopic methods including 1D, 2D NMR, IR, HR-ESI-MS data. Cytotoxic activities against three human cancer A549, HCT116 and SW620 cell lines of the isolated compounds were evaluated by CCK8 method. However, all compounds showed no significant activity against the three cancer cells (IC>100 μM) except for compound , which showed inhibitory effects against HCT116 cells with IC values of 84.6 μM.