Cyanidin, occurrence

Waters, E. J., Peng, Z., Pocock, K. R, Williams, P. J. (1995). Proteins in white wine, I pro-cyanidin occurrence in soluble protein hazes and its relationships to protein instability. Austr. J. Grape Wine Res., I, 86-93. 

Oxalic acid is another dicarboxylic acid with restricted occurrence as an acyl moiety of anthocyanins. In addition to some European orchids flowers (Section 10.5.10), cyanidin 3-dioxalylglucoside has been isolated from fruits of Rubus laciniatus. Altogether six different anthocyanins acylated with oxalic acid have been reported. With the exception of cyanidin 3-[6-(oxalyl)glucoside], evidences for proper determination of the linkage position of this acyl moiety are absent. 

Figure 2.21 Structures of betanldln and a typical anthocyanidin, cyanidin, accumulating as various glycosylated structures and their acylated forms. Both compounds exhibit similar max values. Occurrence of these two classes of pigments mutually excludes each other. The betalains are exclusively found in most families of the plant order Caryophyllales, whereas the anthocyanins are ubiquitously distributed in the other families of the Angiosperms.

Ipomoea (Fig. 6.11) and Evolvulus. Anthocyanins found in these two convolvula-ceous genera are family-specific. Ipomoea represents the most studied genus of this family as far as anthocyanins are concerned. It is noticeable that the occurrence of anthocyanidins is confined to pelargonidin, cyanidin and its 3 -methyl ether peonidin, whereas 3, 4, 5 -trisubstituted analogues, i.e., delphinidin as well as its melhylated congeners petunidin and malvidin, are lacking (Table 6.1). However, delphinidin-based... 

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