Water-soluble Red Pigments Research Articles

Anthocyanins in Ferns

THE water-soluble red pigments present in young fern fronds do not seem to have been investigated since Price, Sturgess, Robinson and Robinson1 in 1938 reported that unusual flavylium salts, resembling 6-hydroxypelargonidin or 6-hydroxycyanidin in their colour preperties, occurred in eight ferns. Recent phytochemical interest in the phenolic constituents of lower plants2 and the discoveries of luteolinidin (I, R = OH) in the moss Bryum3 and of an unidentified anthocyanidin in a fungus4 suggested that the fern pigments would bear re-investigation.

Anthocyanins of blood oranges.

THE fleshy endocarp of the blood orange, a variety of sweet orange, Citrus sinensis, contains a water-soluble red pigment which Matlack1 showed to be anthocyanin in nature.

Colorimetric determination of cytochrome C oxidase by formation of a quinodediimonium pigment from dimethyl- p-phenylenediamine

A simple colorimetric method for the micro-determination of cytochrome oxidase based on the formation of a water-soluble red pigment from dimethyl- p-phenylenediamine, is described. The formation of “quinonediimonium red” is proportional to the concentration of cytochrome oxidase (mitochondrial suspensions from the kidney of the rat containing 1 to 30 μg of N) and to the time of incubation during the first 1 to 3 minutes. The method was tried out with various animal and plant tissues.