Anthocyanins from a Norwegian potato cultivar

The main anthocyanins of purple sprouts of a Norwegian potato cultivar, Solanum tuberosum L., were isolated from a purified methanolic extract by preparative HPLC. Their structures were determined to be the novel anthocyanins, petunidin 3-O-[6-O-(4-O-E-caffeoyl-O-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside (1) (10%) and peonidin, 3-O-[6-O-(4-O-E-caffeoy1-O-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside (2) (6%) in addition to petunidin, 3-O-[6-O-(4-O-E -p-coumaroyl-O-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-g1ucopyranoside, petanin (3) (37%) and peonidin, 3-O-[6-O-(4-O-E-p-coumaroyl-O-α-rhamnopyranosyl)-β-glucopyranoside]-5-O-β-glucopyranoside, peonanin (4) (25%). The same major anthocyanins, however, in other proportions (4, 54, and 32%, for 1, 3, and 4, respectively), were also found in the thin violet zone located in the flesh 0.5–1 cm from the surface of the tubers. This is the first report on anthocyanins from S. tuberosum, which are acylated with caffeic acid.