Flavonoids from the Leaves of Neosinocalamus affinis

Nine flavonoids were isolated from the dry leaves of Neosinocalamus affinis (Rendle) Keng f. The flavonoid structures were determined by spectroscopy using UV, 1D and 2D NMR, and MS. Two new C-glycosyl flavones, tricin-6-C-beta-boivinopyranosyl-8-C-beta-glucopyranoside (1) and 5,7,4'-trihydroxy-3'-methoxy-6-C[beta-D-xylopyranosyl-(1 -> aEuro parts per thousand 2)]-beta-D-glucopyranosyl flavonoside (4), were found in addition to seven known flavonoids, apigenin-6-C-beta-boivinopyranosyl-7-O-beta-glucopyranoside (2), luteolin-6-C-beta-boivinopyranosyl-7-O-beta-glucopyranoside (3), isovitexin-2aEuro(3)-xyloside (5), isoorientin-2aEuro(3)-xyloside (6), tricin-7-O-beta-glucopyranoside (7), isoorientin (8), and tricin (9). This is the first reported isolation of these flavonoids from N. affinis.