Reconstruction of Flower Color of Amherstia nobilis by in vitro Examination

摘要

Flower anthocyanin of Amherstia nobilis has been reported as pelargonidin 3-O-pento-side. However, they were more recently identified as cyanidin 3-O-glucoside and 3-O-xyloside, and peonidin 3-O-glucoside, together with eight flavonol glycosides, i.e. isorhamnetin 3-O-glucoside, 7-O-glucoside, 3,7-di-O-glucoside and 3-O-rutinoside, quercetin 3-O-rutinoside and 3-O-glucoside, and kaempferol 3-O-rutinoside and 3-O-glucoside. Color of cyanidin 3-O-glucoside which is major anthocyanin in the flowers is originally red but not reddish orange. We presumed that color of anthocyanins is hypsochromically shifted under lower pH, and measured pH of the pressed juice of the petals. As the results, it was proved that pH of the petals is lower (pH 3.3) and in spite of flower pigments are cyanidin glycosides, the flowers of A. nobilis express reddish orange. This was followed by in vitro examination.