New flavonol glycosides from the leaves and flowers of Primula sieboidii.

Three flavonol glycosides were isolated from the leaves of Primula sieboldii. They were identified as quercetin 3-O-β-[xylopyranosyl-(1-->2)-β- glucopyranosyl-(1-->6)-β-glucopyranoside] (1), kaempferol 3-O-β-[glucopyranosyl-(1-->2)-β-glucopyranosyl-(1-->6)-β-glucopyranoside] (2) and kaempferol 3- O-β-[xylopyranosyl-(1-->2)-β-glucopyranosyl-(1-->6)-β-glucopyranoside] (3). Their chemical structures were determined by UV, 1H and 13C NMR spectroscopy, LC-MS and acid hydrolysis. Compounds 1 and 3 are found in nature for the first time. They were also detected in the flowers, together with two anthocyanins, malvidin 3,5-di-O-glucoside and a minor petunidin dihexoside.