[Flavonoid constituents of Melicope triphylla MERR.II]

From the leaves of Melicope triphylla MERR., three new flavonoids (1-3) were isolated, together with nine known flavonoids, 4',5-dihydroxy-3,3',7- trimethoxyflavone (4), 5-hydroxy-3,3',4',7-tetramethoxyflavone (5), 3,3',4',5,7-pentamethoxyflavone (6), 7-hydroxy-3,3',4',5,8-pentamethoxyflavone (7), 3,3',4',5,7,8-hexamethoxyflavone (8), 5-hydroxy-3,7,8-trimethoxy-3',4'-methylenedioxyflavone (9), 7-hydroxy-3,5,8- trimethoxy-3',4'-methylenedioxyflavone (10), 3,5,7,8-tetramethoxy-3',4'-methylenedioxyflavone (11), and 5-hydroxy- 3,6,7,8-tetramethoxy-3',4'-methylenedioxyflavone (12). The structures of 1, 2, and 3 were established as 5-hydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone, 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3',4'-methylenedioxyfl avone, and 4'-hydroxy-7-isopentenyloxy-3,3',5,8-tetramethoxyflavone by their respective chemical and spectral data. The 20 flavonoids isolated from this plant were examined for the piscicidal activities.