Two new quercetin glycoside derivatives named quercetin-3-O-[2-O-trans-caffeoyl-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside] (1) and quercetin-3-O-[2-O-trans-caffeoyl-β-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranoside] (2) along with three known flavonoids, 5-hydroxy-6,7,3',4',5'-pentamethoxyflavone (3), 5,7-dihydroxy-8-methoxyflavone (4) and kaempferol 3-O-β-D-glucopyranoside (5), were isolated from the fruits of Gardenia jasminoides var. radicans. The structures of the new compounds were determined by means of extensive spectroscopic analysis (1D, 2D NMR and HR-ESI-MS), glycoside hydrolysis and sugar HPLC analysis after derivatisation. This is the first report on the isolation of a pair of compounds with α or β-L-rhamnopyranosyl configuration from plant and the first detail assignment of their NMR data.
Keywords: Gardenia jasminoides var. radicans; flavonoids; quercetin glycosides.