Five new flavonoids, 5,8-dihydroxy-3,7-dimethoxy-3',4'-methylenedioxyflavone (1), 7-hydroxy-3,5-dimethoxy-3',4'-methylenedioxyflavone (2), 7-(2,3-dihydroxy-3-methylbutoxy)-3,5-dimethoxy-3',4'-methylenedioxyflavone (3), 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5-tetramethoxyflavone (4), and 7-(2,3-dihydroxy-3-methylbutoxy)-3,3',4',5,8-pentamethoxyflavone (5), were isolated from the leaves of Melicope triphylla. In addition, six known flavonoids were detected: 3,4',5-trihydroxy-3',7,8-trimethoxyflavone (6), 5,7-dihydroxy-3-methoxy-3',4'-methylenedioxyflavone (7), 4',5,7-trihydroxy-3,3'-dimethoxyflavone (8), 4',7-dihydroxy-3,3',5,8-tetramethoxyflavone (9), 4',7-dihydroxy-3,3',5-trimethoxyflavone (10), and 4',5,7-trihydroxy-3,3',8-trimethoxyflavone (11). The new compound structures were determined by spectroscopic methods. Compounds 1-5 did not exhibit any ichthyotoxic activity against Japanese killifish (medaka in Japanese) (Oryzias latipes var.) at 10 ppm.

Regular ArticleMelicope triphylla MERR. (Rutaceae) (Awadan in Japanese) is a shrub growing in Southeast Asia. Many flavonoids have been isolated from the leaves [1][2][3][4] and the root and stem bark 1,[5][6][7] of this plant. Some of them have been reported to show piscicidal, 2) antiplatelet aggregating, 3) cytotoxic 4) and vasorelaxing activities.7) In a follow-up investigation, we obtained four new compounds (1-4) and two other known compounds 5 and 6 from the leaves. In this study, we report the isolation and structure elucidation of these new compounds. Results and DiscussionAfter chromatographic separation, the methanol extract of the M. triphylla fresh leaves yielded 5-hydroxy-3,7-dimethoxy-3Ј,4Ј-methylenedioxyflavone (5) 2) and 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3Ј,4Ј-methylenedioxyflavone (6), 2) and four new compounds 1-4, in addition to methyl p-geranyloxy-trans-cinnamate and b-amyrin.Compound 1 (yellow needles) showed a positive response to the magnesium-hydrochloric acid test for flavonoids. The IR spectrum of 1 showed peaks at 3300 and 1649 cm Ϫ1 assigned to the hydroxy and a,b-unsaturated carbonyl groups, respectively. The molecular formula of 1 was deduced as C 18 H 14 O 8 by high resolution (HR) electron ionization (EI)-MS (M ϩ m/z 358.0685) (Calcd 358.0687). The UV spectrum of 1 in methanol displayed a band I absorption maximum at a longer wavelength (l max ϭ378 nm), suggesting that compound 1 is a flavonol. Band I showed a bathochromic shift (Dl max ϭ40 nm) upon NaOMe addition, supporting the presence of a 3-hydroxy group. It also exhibited a bathochromic shift (Dl max ϭ63 nm) upon addition of AlCl 3 -HCl mixture, consistent with the presence of a 5-hydroxy group.8) The 1 H-NMR spectrum of compound 1 (Table 1) (1H, dd, Jϭ2.0, 8.3 Hz, H-6Ј)], suggesting that C-3Ј and C-4Ј were substituted in the B-ring. The EI-MS spectrum showed a diagnostic peak at m/z 149 corresponding to the (OCH 2 O)C 6 H 3 -CϵO ϩ fragment (Chart 1), consistent with a 3Ј,4Ј-methylenedioxy substitution pattern for the B-ring.9) The 13 C-NMR spectrum (Table 2) showed that one methoxy carbon resonated at 56.5 ppm suggesting that none or only one of the ortho positions was substituted. It also showed a peak for another methoxy carbon at 61.0 ppm indicating that both positions ortho to the methoxy were substituted. 10-13) Thus, the substitution pattern of A-ring is 5-hydroxy-6,7-dimethoxy or 5-hydroxy-7,8-di- , 3,5-dihydroxy-7,8-dimethoxy-3,4-methylenedioxyflavone (1), 3,5-dihydroxy-7-methoxy-3,4-methylenedioxyflavone (2), 3,5-dihydroxy-7-isopentenyloxy-8-methoxy-3,4-methylenedioxyflavone (3) and 5-hydroxy-3-isopentenyloxy-7-methoxy-3,4-methylenedioxyflavone (4), were isolated from the leaves of Melicope triphylla. In addition, two known flavonoids were detected including 5-hydroxy-3,7-dimethoxy-3,4-methylenedioxyflavone (5) and 5-hydroxy-7-isopentenyloxy-3,8-dimethoxy-3,4-methylenedioxyflavone (6). The structures of the new compounds were established by spectroscopic methods. Isolation of Four New Flavonoids from Me...

Six new flavonoids-5-hydroxy-3,8-dimethoxy-3′,4′:6,7-bismethylenedioxyflavone (1), 3,3′,4′,5-tetramethoxy-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.

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Analgesic effect of Keishi-Ni-Eppi-Itto-ka-Ryo-Jutsu-Bu (KNE), a traditional herbal medicine against rheumatoid arthritis, on writhing reaction induced by acetic acid was investigated in mice. KNE, composed of gypsum, Zizyphi fructus, Cinnamomum cortex, Ephedrae herba, Paeoniae radix, Glycyrrhiza, ginger, Atractylodis rhizoma and hoelen, significantly depressed the writhing reaction, while Aconiti tuber, widely used for analgesic purpose, did not affect the reaction. The depressive action of each KNE component was examined. It was found that only Ephedrae herba showed significant dose-dependent depression of the writhing reaction. When the decocted liquid of Ephedrae herba was separated to aqueous layer and benzene layer at low pH, followed by high pH, the aqueous layer showed remarkable dose-dependent depression of the writhing reaction.