Acylated anthocyanins in the flowers of Vanda (Orchidaceae)

More than 11 anthocyanins were observed in the violet-blue and red-purple flowers of Vanda hybrid cultivars (Orchidaceae), from which eight major acylated anthocyanins were isolated. Font of those pigments were based on cyanidin 3,7,3'-triglucoside and the other four pigments were based on delphinidin 3,7,3'-triglucoside as their deacylanthocyanins, which were acylated with two molecules of hydroxycinnamic acid and/or one molecule of malonic acid, respectively. Apart from four known acylated anthocyanins, two novel anthocyanins were unambiguously elucidated to be delphinidin 3-O-[6-O-(malonyl)-beta-glucopyranoside] -7,3'-di-[6-O-(trans-sinapoyl)-beta-glucopyranoside] and its demalonyl derivative by spectral and chemical methods. Another novel anthocyanin was determined to be delphinidin 3-O-malonylglucoside-7,3'-diferuloylglucoside by chromatographical methods. One further acylated anthocyanin was tentatively identified to be sinapoylferuloyl 3-malonylglucoside-7,3'-diglucoside of delphinidin. The distribution of these pigments was investigated in the flowers of four species and 13 hybrids by the analytical process of HPLC. Also the flower colour effects of these pigments are discussed. (C) 2004 Elsevier Ltd. All rights reserved.