6 CAPS A NTH IN 241 



1913 A number of investigators establish the spectroscopic similarity of lyco- 



pene to the paprika pigment^^. 

 1927 Zechmeister and von Cholnoky^* succeed in obtaining the pigment of 



Capsicum annuum (paprika) in a crystalline form. They propose the name 



capsanthin for the new carotenoid. 

 1927-35 Zechmeister and von Cholnoky^^, and Karrer and co-workers^^ 



elucidate the constitution of capsanthin. 



Occurrence 



Capsanthin is a rare carotenoid. Zechmeister and von Cholnoky®'' found 

 the esterified pigment in the ripe pods of Capsicum annuum and Capsicum 

 frutescens japonicum^^ and Karrer and Oswald^^ observed that the anthers of 

 Lilium tigrinum contain capsanthin besides antheraxanthin (cf. p. 191). 



Preparation''^ 



The paprika pods are freed from their shells and seeds and dried at 35-40°. 

 The finely ground material is then extracted at room temperature with petroleum 

 ether (1 kg of pods requires % ^ of petroleum ether). The solution is diluted with 

 a threefold volume of ether, 30 % methanolic potassium hydroxide is added, and 

 the mixture is allowed to stand for 1-2 days at room temperature. (Concerning the 

 control of the saponification, compare the original communication of Zechmeister 

 and VON Cholxoky). At the end of this period the free phytoxanthins are dissolved 

 in ether. The solution is washed until it shows a neutral reaction, dried over sodium 

 sulphate, and most of the solvent is evaporated under reduced pressure. The 

 ethereal residue is diluted with much petroleum ether and allowed to stand in the 

 cold for 24 hours. In this way, 1.2-2 g of crude capsanthin is obtained from 1 kg of 

 high quality paprika. After two recrystallisations from carbon disulphide, the yield 

 amounts to 0.8-1.2 g of crystallised, but still inhomogeneous pigment. The sepa- 

 ration from accompanying carotenoids (zeaxanthin, capsorubin) is effected by 

 chromatography on calcium carbonate or zinc carbonate. Carbon disulphide is 

 employed as solvent for developing the chromatogfam. A mixture of benzene and 

 ether (1:1) is also suitable for this purpose''^. 



Cht>micul Constitution 

 CM, CH, CH, CH, 



C CH, CH3 CH3 CH3 C 



/\ II II /\ 



CH- C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-CO CH3 



r II I 



HOCH C-CHj HaC-CHa CHOH 



\ / Capsanthin \ y^ 



CHg CH2 



The molecular formula of capsanthin CjoHggOa was determined by Zech- 

 meister and VON Cholnoky'^'^. The same authors also established that the 



References p. 253—255. 

 Carotenoids 16 



