Anthocyanins from maize (Zea mays) and reed canarygrass (Phalaris arundinacea)

Flowers of maize, Zea ma,ys, and reed canarygrass, Phalaris arundinacea, contain the same anthocyanins: cyanidin 3-glucoside, cyanidin 3-(6"-malonylglucoside), cyanidin 3-(3",6"dimalonyl-glucoside) peonidin 3-glucoside, peonidin 3-(6"-malonylglucoside), and peonidin 3-(dimalonylglucoside). The latter pigment has previously not been reported to occur in plants. Structure elucidations were primarily based on homo- and heteronuclear two-dimensional NMR and electrospray MS. During the isolation procedure using various mixtures of H2O, CF3CO2H, and CH3OH, and during storage in NMR solvent (CF3CO2D/CD3OD; 1.19, v/v) methyl esterification of the free acid function of the malonyl units of the pigments occurs. The acylated anthacyanins constitute more than 80% and 40% of the anthocyanins in P. arundinacea and Z. mays, respectively. Flowers and leaves of maize, Zea mays, contain the same anthocyanins in nearly equal relative proportions.