50 青色花色素アシル化アントシアニン類の構造,特にツユクサの青色色素コンメリニンの構造について

概要

論文の詳細を見る
Anthocyanins are usually unstable in neutral or weakly acidic aqueous solutions, but recently a few acylated anthocyanins have been found to be stable in such aqueous solutions. For clarification of the cause of such stabilization, complete structure and stereochemistry of the pigments must be determined. We report herewith the complete structure of two of such anthocyanins; namely, heavenly blue anthocyanin (1) from Ipomoea and gentiodelphin (7) from Gentiana makinoi. Deacylation of these pigments causes destabilization of their color. To explain the stabilization effect of the acyl groups, we propose a model in that the long side chain in (1) is wound round the anthocyanidin nucleus so that two molecules of caffeic acid stand front and back sides of the anthocyanidin chromophore face to face, thus stabilizes the chromophore by hydrophobic interaction among the aromatic nuclei. Commelinin is a blue pigment obtained from Commelina and reported to consists of two molecules each of awobanin (11) and flavocommelin (12) accompanied by one atom each of Mg and K. We clarified that awobanin (11) is an artefact and true anthocyanin in the pigment is actually protoawobanin (13). This result made clear why commelinin moves toward anode in the electrophoresis in weakly acidic media.
天然有機化合物討論会の論文
1982-09-10