Stilbenoids from the roots of Stemona tuberosa.

Two new stilbenoids, stemobenoids A (1) and B (2), together with three known compounds were obtained from the roots of Stemona tuberosa. The structures of the new compounds were established by extensive spectroscopic analysis, including HRMS, 1D and 2D NMR data. Compounds 1 and 2 displayed potent quinone reductase inducing activity in Hepa 1c1c7 cells.