CAROTENOLS AND OXYCAROTENOLS OF THE C40 SERIES 575 



conifers Taxiis (yew), and Gnetum (joint fir), from which Monteverde and 

 Lyubimenko^^*'^*^ were able to prepare crj^stals. Tswett'" separated this 

 pigment chromatographically from a series of plants, including Taxus 

 hnccata (English yew), the cypresses, Cupressus naifnocki and Chamaecy- 

 para {Retinispora) pisifera phimosn{p\ume false cypress), and the eastern 

 cedar {Junipcrus virginiana). It was named thujorhodin because of its 

 presence in the Thuja orientalis L. (Oriental arborvitae), whose leaves turn 

 red after exposure to frost. 



1£. Capsanthin 



As early as 1817, Braconnot^" carried out studies on the pigment of the 

 paprika. Thudichum^^ was the first to recognize that this coloring matter 

 is related to the carotenoids, and this theory was later substantiated by 

 others. ^^^- ^^^ Although a number of workers found that the spectroscopic 

 absorption corresponded to that of lycopene,^"^-^^^-*" the proof that it was a 

 new specific substance was established when Zechmeister and Cholnoky^^^ 

 succeeded in crystallizing the pigment from the paprika {Capsicum fru- 

 tescens). They chose the name capsanthm for this new pigment. Capsan- 

 thin appears to be formed when the green pods develop a strong red 

 coloration. The biosynthesis of capsanthin results from the interaction of 

 some precursor with oxygen. 



A number of other polyene pigments appear to be associated with 

 capsanthin. These include capsorubin and the carotenols, lutein, crypto- 

 xanthin, and zeaxanthin. Capsanthin itself is an alcohol. In paprika, 

 neither capsanthin nor the other carotenols occur as free alcohols, but they 

 are present as the esters, since they cannot be extracted without saponifica- 

 tion. Myristic, palmitic, stearic, oleic, and carnaubic acids are the chief 

 acids with which the carotenols are esterified in the fruit. It is therefore 

 evident that the polyene esters of the capsicum fruit do not form a single 

 chemical compound but a mixture of a number of different esters of each of 

 a series of carotenols. These have been referred to by Zechmeister^' as 

 colored fats; they are discussed at length in Chapter IV. 



a. Structure. Zechmeister and Cholnoky^*^ were the first to demon- 

 strate that the red pigment of capsicum fruit (Capsicum frutescens L.) is 

 not a hydrocarbon. Although their first empirical formula was given as 

 C34H48O3, it was later revised to CssHsoOs,^®' and finally again changed to 



3«^ H. Bracounot, Ann. chim. [2], 6, 122-141 (1817). 



'« T. Pabst, Arch. Pharm., 230, 108-134 (1892). 



^^^ F. G. Kohl, Untersuchungen iiber das Carotin und seine physiologische Bedeutung in 

 Pflanzen, Bomtraeger, Leipzig, 1902. Cited b\- P. Karrer and P'. Jucker, Carotinoide. 

 Birkhauser, Basle, 1948, p. 245. 



'«^ A. Tschirch, Ber. deut. botan. Ges., 22, 414-439 (1904). 



3«« L. Zechmeister and L. v. Cholnoky, Ann., 454, 54-71 (1927). 



'«' L. Zechmeister and L. v. Cholnoky, Ann., 4S7, 197-213 (1931). 



