Acylated Delphinidin Glycosides from Violet and Violet-Blue Flowers of Clematis Cultivars and their Coloration

Abstract

Three new acylated delphinidin glycosides, delphinidin 3- O-β-[(2″- trans-caffeoylglucopyranosyl)-(1→2)-(6″-succinylgalactopyranoside)]–7- O-β-glucopyranoside (1), delphinidin 3- O-β-[(2″- trans-caffeoylglucopyranosyl)-(1→2)-(6″- trans-caffeoyl-tartaroyl-malonylgalactopyranoside)]–7- O-β-glucopyranoside (2), and delphinidin 3- O-β-[(2″- trans-caffeoylglucopyranosyl)-(1→2)-(6″- trans-caffeoyl-tartaroyl-malonylgalactopyranoside)]–3′- O-β-glucuronopyranoside (3), were isolated from the violet and violet-blue sepals of Clematis cultivars ‘Jackmanii Superba’ and ‘Fujimusume’. The chemical structures of the isolated anthocyanins were determined by LC-MS, characterization of hydrolyzates, and UV, 1H and 13 C NMR spectroscopy. The visible absorption spectra of these anthocyanins were compared with those of fresh sepals and crude extracts in pH 5.1 buffer solution. In addition, the co-pigment effect with some kaempferol glycosides and caffeoylglucose was examined.