A BLUE PIGMENT COMPLEX IN FLOWERS OF SALVIA PATENS

A blue pigment complex, protodelphin, was isolated from the blue flowers of Salvia patens. The absorption spectrum of its aqueous solution has two maxima in the visible region and the blue complex is stable in neutral or acidic aqueo us solution. Protodelphin was shown to be composed of delphinidin 3 -(6''-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 awobanin, apigenin 7,4'-diglucoside and magnesium. The yield of the blue pigment was to a certain extent proportional to the amount of magnesium added to the reaction mixture and the stable blue complex was not obtained without this element, Similar blue complexes were formed by the use of manganese, cobalt, nickel, zinc and cadmium instead of magnesium. The results show the true blue colour of the flowers is manifested by the metallo-anthocyanin which contains magnesium as chelating metal and is a similar complex to commelinin.