Acylated cyanidin glycosides from the pale-violet flowers of Ionopsidium acaule (Desf.) Rchb. (Brassicaceae)

Three new acylated cyanidin 3-sambubioside-5-glucosides (1-3) and one new acylated cyanidin 3-(3^X-glucosylsambubioside)-5-glucoside (4) were isolated from the pale-violet flowers of Ionopsidium acaule (Desf.) Rchb., together with one known anthocyanin. These new pigments were determined by chemical and spectroscopic methods to be cyanidin 3-O-[2-O-(β- xylopyranosyl)-6-O-(4-O-(6-O-(trans-feruloyl)-β-glucopyranosyl) -trans-p-coumaroyl)-β-glucopyranoside]-5-O-[6-O-(malonyl) -β-glucopyranoside] (1), cyanidin 3-O-[2-O-(2-O-(trans-feruloyl)-β- xylopyranosyl)-6-O-(4-O-(β-glucopyranosyl)-trans-p-coumaroyl) -β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] (2), cyanidin 3-O-[2-O-(2-O-(trans-feruloyl)-β-xylopyranosyl)-6-O-(4-O-(6-O- (trans-feruloyl)-β-glucopyranosyl)-trans-p-coumaroyl)-β- glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] (3) and cyanidin 3-O-[2-O-(2-O-(trans-feruloyl)-3-O-(β-glucopyranosyl)-β-xylopyranosyl) -6-O-(4-O-(6-O-(trans-feruloyl)-β-glucopyranosyl)-trans-p-coumaroyl) -β-glucopyranoside]-5-O-[6-O-(malonyl)-β-glucopyranoside] (4). These polyacylated cyanidin glycosides are responsible for the pale-violet flower color of I. acaule, and the contribution of the number of hydroxycinnamic acid residues to the bluing effect was discussed.