Acylated flavonol glycosides from cabbage leaves.

Seven flavonol glycosides were isolated from a leaf extract of cabbage and characterized by chemical and spectroscopic methods including 1H and 13C NMR and negative ion FAB-MS. Five compounds were new natural products or were fully characterized for the first time. They are derivatives of kaempferol-3-O-beta-D-sophoroside-7-O-beta-D-glucoside acylated at C-2"' with either caffeic acid, p-coumaric acid or ferulic acid, and of quercetin-3-O-beta-D-sophoroside-7-O-beta-D-glucoside acylated with either caffeic acid or ferulic acid. Kaempferol-3-O-beta-D- sophoroside-7-O-beta-D-glucoside and kaempferol-3-O-beta-D-(2-sinapoylsophoroside)-7-O-beta-D-glucoside were found for the first time in cabbage, but they have previously been found in other Brassica species.