152 CAROTENOID HYDROCARBONS OF KNOWN CONSTITUTION X 



Source 

 Ipomoea Batatas 



Mangifera indica (fruit) 



Marine and deep-sea soil 

 Oedogoniuni 



Oil irom Orthagoriscus mola 

 Palm oil 



Paprica 



Oil from Regalecus 

 Red Euglene 

 Rhodymenia palmata 



Rye-germ oil 



Saffron 



Sorhus aucuparia (fruit) 



Soya beans 



Ulex Gallii 



Yellow maize 



References 

 J. C. Lanzing and A. G. van Veen, Chem. Centr. 

 igjS, I, 2081. 



R. Yamamoto, Y. Osima and T. Goma, Chem. Centr. 

 1933, I, 441. 



D. L. Fox, Chem. Centr. 1937, II, 3899. 

 I. M. Heilbron, E. G. Parry and R. F. Phipers, 

 Biochem. J. 29 (1935) 1376. 

 N. A. S0RENSEN, Chem. Centr. J934, I, 3817. 

 P. Karrer, H. v. Euler and H. Hellstrom, Chem. 

 Centr. 1932, I, 1800. — R. Kuhn and H. Brockmann 

 Z. physiol. Chem. 200 (1931) 255. — P. Karrer and 



0. Walker, Helv. chim. Acta 16 (1933) 641. — R. F. 

 Hunter and A. D. Scott, Biochem. J. 55 (1941) 31. 

 L. Zechmeister and L. v. Cholnoky, Ann. 509 

 (1934) 269. 



N. A. S0RENSEN, Chem. Centr. 1934. I, 3817. 

 H. TiscHER, Z. physiol. Chem. 259 (1939) 163. 



1. M. Heilbron, E. G. Parry and R. F. Phipers, 

 Biochem. J. 29 (1935) 1376. 



H. A. Schuette and R. C. Palmer, Chem. Centr. 



1938, I, 1898. 



R. Kuhn and A. Winterstein, Ber. 6y (1934) 344. 



R. Kuhn and E. Lederer, Ber. 64 (1931) 1349. 



W. C. Scherman, Chem. Centr. 1941, I, 2673. 



K. Schon, Biochem. J. 30 (1936) 1960. 



G. S. Fraps and A. R. Kemmerer, Chem. Centr. 1942, 



II, 1641. 



Preparation 



a-Carotene is widely distributed in plants but never occurs in large concentra- 

 tions. According to Karrer and Walker^*' it is best prepared from commercial 

 carotene (carrot carotene). The pigment can be separated in good yield from 

 /S-carotene by chromatographic adsorption on calcium hydroxide. 



Glass tubes about 70 cm in length and 5 cm in diameter are filled with air-dry 

 calcium hydroxide (cf. p. 27) and the columns are wetted with a little ligroin (b.p. 

 60-70° C). 200 mg of carotene (a mixture of ^, a, and a little y-carotene) are 

 dissolved in about 100 ml of ligroin and the solution is poured on the calcium 

 hydroxide column. The chromatogram is developed with petroleum ether, b.p. 

 70-80°. As soon as the yellow, a-carotene -containing zone has reached the lower 

 end of the tube, the development is interrupted and the pigment is eluted with a 

 mixture of ether and methanol (10:1). After evaporating the solvent, the pigment 

 remains as a dark -red crystalline mass. For further purification, the a-carotene is 

 crystallised 2-3 times from a mixture of benzene and methanol or from petroleum 

 ether. From 1 g of carotene an average of 80 mg of pure a-carotene are obtained in 

 this way. 



Other methods^*^ of preparation of a-carotene are hardly used, as they are 

 relatively cumbersome and do not furnish pure products. 

 References p. 165-iyo. 



