Isocassiaoccidentalin B, A New C-Glycosyl Flavone Containing a 3-Keto Sugar, and Other Constituents from Cassianomame

Abstract

A new C-glycosyl flavone containing a 3-keto sugar, isocassiaoccidentalin B (1), was isolated from whole Cassianomame (Sieber) Honda plants, along with eleven known compounds, including two flavonoids (2 and 3), five flavonoid glycosides (4-8), two chalcones (9 and 10), and two phenylpropanoids (11 and 12). The chemical structures of all compounds were determined via 1D- and 2D-NMR, and ESI-MS. Among these, compounds 2, 3, 7, and 8 were found to be the most potent in inhibiting nitric oxide release. Compounds 1, 2, 4, 8, 9, and 10 showed significant free-radical scavenging activity.