Covalent anthocyanin-flavonol complexes from flowers of chive, Allium schoenoprasum

The structures of eight anthocyanins have been determined in acidified meth anolic extract of pale-purple lowers of chive, Allium schoenoprasum. Four o f them have been identified as the anthocyanin-flavonol complexes (cyanidin 3-O-beta-glucoside(AII)) (kaempferol 3-O-(2-O-beta-glucosyl(FIII)-beta-glu coside(FII)) -7-O-beta-glucosiduronic acid(FIV)) malonata(AIII) (AII-6 --> AIII-1, FIV-2 --> AIII-3). 1. (cyanidin 3-O-(3-O-acetyl-beta-glucoside(AII) )(kaempferol 3-O-beta-O-B-glucosyl(FIII)-beta-glucoside(FII))-7-O-beta-gluc osiduronic acid(FIV)) malonate(AIII) (AII-6 --> AIII-I, FIV-2 --> AIII-3). 2. and their 7-O-(methyl-O-beta-glucosiduronate(FIV)) analogous, 3 and 4. P igments 1 and 2 are the first final identification of covalent complexes be tween an anthocyanin and a flavonol, while 3 and 4 are formed during the is olation process. The other Four anthocyanins (5-8) were found to be the 3-a cetylglucoside, 3-glucoside, 3-(6-malonylglucoside) and 3-(3,6-dimalonylglu coside) of cyanidin. The three latter pigments have earlier been identified as the major anthocyanins of the chive stem. The covalent anthocyanin-flav onol complexes show intramolecular association between the anthocyanidin (c yanidin) and flavonol (kaempferol) units, which influence the colour. (C) 2 000 Elsevier Science Ltd. All rights reserved.