Provitamin A 2 from Lutein

Alfalfa lipids were treated with p-toluenesulfonic acid in benzene under reflux; after saponification, chromatography of the unsaponifiable portion yielded a carotenoid having a single absorption maximum at 460 mmicro in ethanol and hexane. Its properties correspond to those of the dehydration product of lutein, 3'-hydroxy-3,4-dehydro-ss-carotene, for which the name "anhydrolutein" is proposed. Vitamin A depleted chicks convert this pigment to vitamin A(2), as shown by the high ratio of absorbancies at 693 and 620 mmicro in a mixture of CHCI(3) and SbCl(3). and the absorption maximum at 350 mmicro in hexane exhibited by the liver lipids. The possible role of this pigment in the biogenesis of vitamin A(2) is discussed.