A BLUE PIGMENT COMPLEX IN FLOWERS OF SALVIA PATENS

A blue pigment complex, protodelphin, was isolated from the blue flowe rs of Salvia patens. The absorption spectrum of its aqueous solution h as two maxima in the visible region and the blue complex is stable in neutral or acidic aqueo us solution. Protodelphin was shown to be comp osed of delphinidin 3 ''-p-coumaroylglucoside)-5-(6''-malonylglucoside ), apigenin 7,4'-diglucoside and magnesium. This was confirmed by the in vitro synthesis of protodelphin from its component parts, malonyl a wobanin, apigenin 7,4'-diglucoside and magnesium. The yield of the blu e pigment was to a certain extent proportional to the amount of magnes ium added to the reaction mixture and the stable blue complex was not obtained without this element, Similar blue complexes were formed by t he use of manganese, cobalt, nickel, zinc and cadmium instead of magne sium. The results show the true blue colour of the flowers is manifest ed by the metallo-anthocyanin which contains magnesium as chelating me tal and is a similar complex to commelinin.