Flavonoids from leaves of Psidum littorale

We investigated the chemical constituents of the leaves of Psidum littorale, which include 16 flavonoids, including seven flavonols, six flavonoid glycosides and three flavonones. The compounds were isolated by silica gel column chromatography. Their structures were elucidated on the basis of spectral analysis and by comparison with published data. Seven flavonols were kaempferol (1), isorhamnetin (2), myricetin-3,7,3'-trimethyl ether (3), laricitrin (4), quercetin (5), myricetin (6) and quercein-3,4'-dimethyl ether (7), six flavonoid glycosides were guaijaverin (8), hyperoside (9), 5,4'-dyhydroxy-3,7,5'-methoxyflavone-3'-O-β-D-glucoside (10), laricitrin-3-O-xyloside (11), myricetin-3-O-α-L-rhamnopyranoside (12) and myricetin-3-O-β-D-xyloside (13). Three flavonones were 4'-O-methyldihydroquercetin (14), dihydroapigenin (15) and ampelopsin 4'-O-β-D-glucopyranoside (16). Compound 10 is a new chemical, compounds 2-4, 7, 10-16 were first isolated from this plant. ¹H NMR and ¹³C NMR data of compound 11 were not reported in literature.