Diarylheptanoid glycosides from Dioscorea nipponica rhizomes.

A group of previously undescribed diarylheptanoids with mono/di-glucose substitution, diodiarylheptosides A-F (1-6), together with six known diarylheptanoids (7-12) were isolated from the rhizomes of Dioscorea nipponica. Their structures were established by comprehensive UV, IR, HR-ESI-MS and NMR analyses, and their absolute configurations were determined by a comparison of calculated and experimental ECD, some with optical rotations, after acid-hydrolysis. Moreover, bioassay results showed that compounds 3 and 11 exhibited stronger NO inhibitions on lipopolysaccharides-induced RAW 264.7 cells, with the IC50 values of 14.91 ± 0.62 and 12.78 ± 1.12 µM.