Bioactive constituents from the rhizomes of Dioscorea septemloba Thunb.

Eight new compounds, dioscorosides G (1), H1 (2), H2 (3), dioscorol B (4), dioscorosides I (5), J (6), K1 (7), and K2 (8), together with twelve known ones (9-20) were obtained from the rhizomes of Dioscorea septemloba. Their structures were elucidated by chemical and spectroscopic methods. Among the known isolates, 12-14, 18, and 20 were isolated from the Dioscoreae genus for the first time. While, 9-11, 15, and 16 were firstly obtained from the plant. Moreover, all the isolates were evaluated for in vitro anti-inflammatory potential using LPS-stimulated RAW 264.7 murine macrophages, and compounds 7, 11, 15, and 16 were found to display significant inhibition of nitrite production.