2006 Volume 54 Issue 11 Pages 1530-1534
A new flavanol, erycibenin D, and two new flavans, erycibenins E and F, were isolated from the stems of Erycibe expansa originating in Thailand. The structures of new flavonoids were elucidated on the basis of chemical and physicochemical evidence. In addition, the inhibitory activities of the isolated constituents from E. expansa on lipopolysaccharide-activated nitric oxide production in mouse peritoneal macrophages were examined. Among the principal constituents, two isoflavones, clycosin (IC50=13 μM) and erythrinin B (18 μM), and two rotenoids, deguelin (26 μM) and rotenone (27 μM), were found to show potent inhibitory activity.