Complete Stereostructure Determination of Natural Acylated Anthocyanins, Violanin, Awobanin, and Malonylawobanin, by 'H-NM R

Abstract

Chemical degradation methods for structure determination of natural acylated anthocyanins lose many informations concerning the anomeric configuration and the attaching position of the sugar and the acyl moieties. We have succeeded in obtaining very fine ¹H-NMR spectra of natural anthocyanins such as violanin[1], awobanin [3], and malonylawobanin [2] in their flavylium ion form, and in determining their complete stereostructures. It was found that [2], but not [3], was the real anthocyani n component of commelinin, the sky-blue pigment from Corn melina corn munis.