338 CAROTENOIDS OF UNCERTAIN STRUCTURE XIV 



xanthophyll and probably also into picofulvin, previously observed by 

 Krukenberg. 



Neither canaryxanthophyll nor picofulvin could be obtained in the crystal- 

 line state or investigated in detail, so that their constitutions are still unknown. 

 If the diet contains zeaxanthin, the feathers also assume a yellow colour, but 

 the pigments formed are not identical with those formed from a xanthophyll- 

 containing diet. In this case the pigments appear to be decomposition products 

 of zeaxanthin which do not exhibit sharp absorption maxima. 



The following is a brief summary of the pigments of the feathers of some 

 birds*. 



Bird Pigment 



Bullfinch Red decomposition products 



Canary Canaryxanthophyll 



Green finch Canaryxanthophyll, xanthophyll 



Grey wagtail Xanthophyll 



Oriole Xanthophyll, canaryxanthophyll 



Weaver Xanthophyll, canaryxanthophyll, decomposition 



products 



Woodpecker Picofulvin, xanthophyll 



Canaryxanthophyll exhibits absorption maxima at 472, 443 and 418 m/i 

 in ethanol. Aqueous 25 % hydrochloric acid produces no displacement of the 

 absorption maxima towards shorter wavelengths in an ethereal solution of the 

 pigment. Picofulvin exhibits absorption maxima at 450 and 424 m/^ in ethanol. 

 This pigment differs from fiavoxanthin in its negative hydrochloric acid reac- 

 tion. Canaryxanthophyll is adsorbed more strongly than xanthophyll on calcium 

 carbonate. 



33. LEPROTIN C40H54 



Leprotin was isolated by Grundmann and Takeda^^ from a pure strain of 

 acid-resisting bacteria of a leper. The same pigment was later found by Takeda 

 and Ohta^^ in Mycobacterium phlei. 



For the isolation of leprotin, the bacteria are dried and extracted with 

 acetone. The extracts are saponified and the pigments of the epiphasic fraction 

 are chromatographed on alumina. After elution and evaporation of the solvent, 

 leprotin is crystalHsed from a mixture of benzene and methanol. The pigment 

 is very similar to ^-carotene but differs from the latter in melting point, in the 

 stronger adsorption on alumina, and in the absence of vitamin A activity^*. 

 The molecular formula of leprotin appears to be C^^Yi^^^. On microhydro- 

 genation 12 mols of hydrogen are absorbed^^. 



Leprotin crystallises from a mixture of benzene and methanol in fine, 



Further information will be found on pp. 92 and 93—95. 

 References p. 341-343. 



