Schinalactone A, a New Cytotoxic Triterpenoid from Schisandra sphenanthera

A new cytotoxic triterpenold, schinalactone A (1), together with two new biogenetically related compounds, schinalactones B (2) and C (3), has been isolated from the roots and stems of Schisandra sphenanthera. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 1 and 2 showed significant cytotoxicity against PANC-1 cell lines with IC50 values of 5.9 and 4.1 mu M, respectively, A plausible biosynthetic pathway of 1 was also postulated.