Isolation of six new flavonoids from Melicope triphylla

Abstract

Six new flavonoids - 5-hydroxy-3,8-dimethoxy-3′,4′:6,7- bismethylenedioxyflavone (1), 3,3′,4′,5-tetrame-thoxy-7-(3- methylbut-2-enyloxy)flavone (2), 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,3′, 4′,5-tetramethoxyflavone (3), 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,5- dimethoxy-3′,4′-methylenedioxyflavone (4), 7-(2-hydroxy-3-methyl but-3-enyloxy)-3,3′,4′,5,8-pentamethoxyflavone (5), and 7-(2-hydroxy-3-methylbut-3-enyloxy)-3,5,8-tri methoxy-3′,4′- methylenedioxyflavone (6) - were isolated from the leaves of Melicope triphylla . In addition, six already known flavonoids were also detected: 5-hydroxy-3,6,7-trimethoxy-3′,4′-methylenedioxyflavone (7), 5,7-dihydroxy-3,3′,4′,8-tetramethoxyflavone (8), 4′,5-dihydroxy-3,3′,7,8-tetramethoxyflavone (9), 3,5,6,7,8-penta methoxy-3′,4′-methylenedioxyflavone (10), 3,5,6,7-tetramethoxy- 3′,4′-methylenedioxyflavone (11), and 3,3′,4′,5,6,7,8- heptamethoxyflavone (12). The structures of the new compounds were established by spectroscopic methods. Compound 2 displayed ichthyotoxic activity against Japanese killifish (medaka in Japanese) (Oryzias latipes var.) at 10 ppm. © 2012 The Pharmaceutical Society of Japan.