532 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



Lycopin. 



Lycopin, the pigment of the tomato, is isomeric with carotin. Willstatter 

 and Escher isolated 1 1 gm. of the pigment from 74 kilos, of tomato preserves, 

 whose dry weight was 5 '6 kg. The material was shaken in portions of 8 kilos, with 

 4 litres of 96 per cent, alcohol. The coagulated mass was strained off, pressed 

 out and again shaken with 2-3 litres of alcohol. The solid was finally pressed 

 out in a hydraulic press and dried in a steam oven. The dry mass was 

 extracted with carbon disulphide in a percolator and the solvent evaporated 

 off in vacuo at 40. The deep red- brown residue was diluted with 3 

 volumes of absolute alcohol, filtered off on a porcelain funnel and washed 

 with petrol ether. The product was purified by crystallisation from gasolin 

 of boiling-point 50-80 of which 4-5 litres are required to dissolve i gm. of 

 lycopin, or by solution in carbon disulphide and precipitation with absolute 

 alcohol. 



Carotin is also present in the tomato. 



THE LIPOCHROMES. 



The yellow or orange- red pigments occurring in animals are generally 

 grouped together under the term lipochromes. Thudichum and Schunck 

 showed that they were related to the yellow vegetable pigments. They have 

 also been investigated by Wilstatter and Escher who have isolated 0-45 gm. 

 of carotin from 10,000 ovaries. 



Lutein, the yellow pigment of egg-yolk, is isomeric with xanthophyll ; 

 4 gm. of impure and 2-6 gm. of pure lutein have been isolated from 6000 

 yolks. 



The yellow pigment of butter fat has been shown by Palmer and Eckles l 

 to consist mainly of carotin ; xanthophyll is also present. These pigments 

 are taken up from the food of the cow, the colour of the milk or butter de- 

 pending greatly upon the amount of the pigments in the food given. These 

 workers have further shown that the pigment of the body fat and blood 

 serum of cows is also carotin and xanthophyll. The carotin is apparently 

 present in the blood serum in combination with albumin. This combination 

 and the greater stability of carotin to the digestive juices accounts for its 

 presence in greater amount in the animal tissues, as well as the greater solu- 

 bility of xanthophyll in bile which leads to its excretion in the faeces. 



It might be noted that carotin has been isolated from gall-stones by 

 H. Fischer and Rose. 



1 J. Biol. Chem., 1914, 17. 



