32 CANARYXANTHOPHYLL 337 



31. HAEMATOXANTHIN 



During investigations of the spores of Haematococcus pluvialis, Tischer^^ 

 found, besides jS-carotene, a-carotene*, xanthophyll, zeaxanthin andastacene**, 

 a previously unknown carotenoid for which he proposed the name haemato- 

 xanthin. 



About 6 g of the red spores of Haematococcus pluvialis were available for the 

 isolation of the carotenoid. The spores were ground with quartz sand under acetone 

 and exhaustively extracted with this solvent at room temperature. The extract was 

 diluted with water and the pigments were extracted with petroleum ether. After 

 removing the solvent by distillation, a red resinous residue remained which was 

 dissolved in a little petrol and saponified with methanolic potassium hydroxide. 

 The pigments were then divided in the usual way into epiphasic and hypophasic 

 fractions and the epiphasic fraction was adsorbed on a column of calcium hydroxide. 

 A very small quantity of haematoxanthin was eluted from the upper part of the 

 chromatogram with alcohol-containing petrol and recrystallised from petrol. The 

 pigment could not be obtained entirely pure because of lack of material. 



It is not yet known whether haematoxanthin occurs in algae as an ester^". 

 The constitution of the pigment is unknown. 



Haematoxanthin is entirely epiphasic on partition between petroleum ether 

 and 90 % methanol. If 95 % methanol is employed, the lower layer is also 

 weakly coloured. The crude material melts at 205°. The pigment crystallises 

 from petrol in brown-violet leaflets. 



Solvent: Absorption range Absorption maxima 



Carbon disulphide 463-563 513 m/x 



Petrol (b.p. 70-80") .... 450-515 478 m/z 



Ether 445-515 480 m/i 



32. CANARYXANTHOPHYLL AND PICOFULVIN 



In the course of their investigations of the yellow pigments of different 

 birds, Brockmann and Volker^^ found that the carotenoids present were 

 derived mostly from xanthophyll or, occasionally from zeaxanthin***. By 

 means of feeding tests, these authors were able to prove that the feathers of 

 canaries only attain a yellow colour if the diet contains xant hophyll or zea- 

 xanthinf. In the digestive tract, the xanthophyll is converted into canary- 



J. TiscHER, Z. physiol. Chem. 2^2 (1938) 225. 

 ** In his paper, J. Tischer reports the isolation of "Euglenarhodon". This carotenoid 

 later proved to be identical with astacene and thus does not require a special name. 



The yellow pigment of the budgerigar (Melopsitfacus undulatus) is not a carotenoid. 



f Polyene pigments such as jS-carotene, lycopene, violaxanthin and taraxanthin are 



not assimilated by birds. In canaries which have turned white by being kept on a suitable 



diet, the yeUow colour is only restored on feeding xanthophyll or zeaxanthin, but not 



on feeding a carotenoid hydrocarbon, or violaxanthin or taraxanthin. 



References p. 341-343. 

 Carotenoids 22 



