Acylated pelargonidin glycosides in red-purple flowers of Ipomoea purpurea

Article abstract of DOI:10.1016/S0031-9422(96)00501-8

Four acylated pelargonidin glycosides were isolated from the red-purple flowers of Ipomoea purpurea. The acylated anthocyanins were all based on pelargonidin 3-sophoroside-5-glucoside, acylated with caffeic acid and/or glucosylcaffeic acids. Three novel anthocyanins were elucidated to be pelargonidin 3-O-[2-O-(6-O-(trans-3-O-(β-D-glucopyranosyl)-caffeyl)-β-D- glucopyranosyl)-6-O-(trans-4-O-(6-O-(trans-caffeyl)-β-D-glucopyranosyl)- caffeyl)-β-D-glucopyranoside]-5-O-[β-D-glucopyranoside], pelargonidin 3-O- [2-O-(6-O-(trans-caffeyl)-β-D-glucopyranosyl)-6-O-(trans-4-O-(6-O-(trans- caffeyl)-β-D-glucopyranosyl)-caffeyl)-β-D-glucopyranoside]-5-O-[β-D- glucopyranoside] and pelargonidin 3-O[2-O-(6-O-(trans-caffeyl)-β-D- glucopyranosyl)-6-O-(trans-caffeyl)-β-D-glucopyranoside]-5-O-[β-D- glucopyosdide]. Another anthocyanin was pelargonidin 3-O-[2-O- (glucosylcaffeylglucosyl)-6-O-(caffeyl)-glucoside]-5-gluoside, which was reported to be present in the red-purple flowers of Pharbitis nil. Apart from the second pigment cited, these are analogous pigments of the violet blue Ipomoea anthocyanins which are composed of acylated cyanidin glycosides, instead of pelargonidin.