New phenanthrene glycosides from Dioscorea opposita.

Two new phenanthrene glycosides, dioscopposide A and dioscopposide B (1 and 2), were isolated from the rhizomes of Dioscorea opposita. Their structures were determined primarily on the basis of 1D and 2D NMR techniques, MS studies, and chemical methods. All the isolates were evaluated for their inhibitory effects on the lipopolysaccharide-induced nitric oxide production using murine macrophage RAW 264.7 cells. The IC₅₀ values of dioscopposide A and dioscopposide B were 5.8 and 7.2 μM, respectively. [ABSTRACT FROM AUTHOR]