Two new quercetin glycoside derivatives from the fruits of Gardenia jasminoides var. radicans

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.