Three megastigmane glycosides from the stem of Mallotus barbatus

Three undescribed megastigmane glycosides, mallbarbalosides A-C (1-3) together with 3 known analogues (4-6) were isolated from the stem of Mallotus barbatus. Their structures were elucidated using extensive NMR spectroscopic methods (1D and 2D-NMR spectroscopy) and HRESIMS spectroscopic data analyses. The absolute configurations of the undescribed compounds were determined by the experimental circular dichroism spectroscopy. All the compounds were tested for their inhibitory effects on the production of NO in LPS-treated RAW 264.7 cells, and they showed no inhibitory effect to NO release.