Prenylated flavonoids from the heartwood of Artocarpus communis with inhibitory activity on lipopolysaccharide-induced nitric oxide production

A new prenylated chalcone, 3 '', 3 ''-dimethylpyrano[3', 4'] 2,4,2'-trihydroxychalcone ( 1), was isolated from the heartwood of Artocarpus communis. Two flavonoid derivatives, (-)-cycloartocarpin (9) and (-)-cudraflavone A ( 10), were isolated as new isomers. In addition, eight known flavonoids, isobacachalcone ( 2), morachalcone A ( 3), gemichalcones B ( 4) and C ( 5), artocarpin ( 6), cudraflavone C ( 7), licoflavone C ( 8), and (2S)-euchrenone a(7) (11), were isolated and identified from this plant for the first time. Compounds 1-4, 6, and 11 exhibited potent inhibitory activity on nitric oxide production in RAW264.7 LPS-activated mouse macrophage cells with IC50 values of 18.8, 6.4, 16.4, 9.3, 18.7, and 12.3, mu M, respectively. The structure of compound 1 was elucidated by spectroscopic data analysis, including 1D and 2D NMR experiments.