Abstract
The studies of anthocyanin proceeded over one century from the beginning of 20th century in Japan. For the mechanism of color appearance, three hypotheses are well known: pH theory proposed by Willstatter, metal-complex theory by Shibata and co-pigment theory by the Robinson's. For metal complex, Hayashi et al. studied in detail the blue pigment commelinin isolated from dayflower; the three dimensional structure was now determined by Japanese researchers. For co-pigmentation, novel anthocyanins, which are very stable in neutral solution, were isolated in succession from the purple flowers of bell flower and Cineraria. These anthocyanins were acylated with above two molecules of aromatic organic acids. Japanese researchers clarified the structures and the mechanism of color stabilization of these polyacyl-anthocyanins by NMR. Concerning pH theory, although the studies using press juice were popular before,the mechanism of pH change is made clear now in cell level using micro technique. Recently,the production of Blue Rose was completed by Santory company in Japan. This gave a dream to anthocyanin researchers. I will describe future directions of anthocyanin studies in this section.
