A New Type of Plant Lipochrome

Abstract

IN continuation of our investigations upon the Algæ¹, we have observed the presence of a peculiar carotenoid in the unsaponifiable fraction of one of the Cyanophyceæ (Myxophyceæ), namely, Rivularianitida. The pigment, for which we propose the name myxoxanthin, crystallises from ether-methyl alcohol in deep copper-coloured needles, m.p. 117°–118° (uncorr.), and unlike any other phytocarotenoid hitherto isolated, exhibits only one absorption band, having its head at 488–490 m in carbon disulphide. In this respect myxoxanthin resembles the Crustacean pigment astacene²; but unlike the latter, it has no acidic properties and is completely epiphasic when subjected to the Kraus partition between methyl alcohol and light petroleum. Its failure to yield a sodium salt precludes the possibility of its being hæmatochrome, which pigment is reputed to exist in certain Algæ and is likewise stated to possess only a single absorption band³.