Major flavonoids from Arabidopsis thaliana leaves.

The three major flavonoids isolated from Arabidopsis thaliana plants grown in the greenhouse were identified by means of spectroscopic analysis (UV, NMR, MS) and chiral capillary zone electrophoresis as the novel kaempferol 3-O-beta-[beta-D-glucopyranosyl(1-->6)D-glucopyranoside]-7-O-alpha-L- rhamnopyranoside (1), kaempferol 3-O-beta-D-glucopyranoside-7-O-alpha-L-rhamnopyranoside (2), and kaempferol 3-O-alpha-L-rhamnopyranoside-7-O-alpha-L-rhamnopyranoside (3). Comprehensive NMR studies including selective 1D and gradient-enhanced 2D techniques were applied in order to achieve full signal assignment and definitive proof of linkage for compound 1.