Megastigmane glucosides isolated from Dichrocephala benthamii.

The present study was designed to investigate the chemical constituents of the whole herb of Dichrocephala benthamii. A new megastigmane glucoside (compound 1), together with its four known analogues (compounds 2-5), was obtained. Their structures were elucidated on the basis of spectroscopic analyses (UV, IR, MS, and 1D and 2D NMR). The absolute configuration of compound 1 was assigned on the basis of CD method and chemical evidence. In addition, their cytotoxicity against human hepatoma cells (HepG-2) was evaluated by the MTT method. Compound 5 showed weak activity against HepG-2, while the other compounds did not show remarkable inhibitory effects.