Chapter II 

 Carotinoids in the Phanerogams 



There is no special reason, either physiological or genetical, for 

 considering the carotinoids in the phanerogams and cryptogams sepa- 

 rately, as is done in this and the subsequent chapter. In fact, there 

 appears to be no logical reason for subdividing the plants into groups 

 in connection with the distribution of carotinoids, inasmuch as the 

 pigments appear to be widely distributed in all forms, both chloro- 

 phyllous and non-chlorophyllous, from bacteria to dicotyledons. The 

 subdivision, then, is merely one of convenience. 



The Pigments of the Carrot 



The pigment of the carrot root (Daucus carota) was first described 

 by Wachenroder (1826), nearly 100 years ago, and called carotin by 

 him. This serves as the starting point of our knowledge of the prop- 

 erties, as well as the nomenclature of the carotinoids, and this pigment 

 today represents our most typical chromolipoid. For this reason the 

 carrot pigment will be considered first. 



Wachenroder made an ether extract of the dried macerated roots, 

 or the coagulum obtained on heating the carrot juice. The golden 

 yellow salve-like residue left on evaporation of the solvent was shaken 

 repeatedly with ammonia to separate admixed fatty material, dis- 

 solved again in ether and the ether allowed to evaporate slowly with 

 addition of small amounts of alcohol. Ruby-red quadratic crystals, 

 imbedded in fatty material, were obtained. Wachenroder described 

 the crystals as tasteless and odorless, soluble in alcohol and ether, 

 readily soluble in fats and ethereal oils, but insoluble in acetic acid 

 and alkalis. 



Vauquelin -and Bouchardat (1830) are credited with the next study 

 of the carrot pigment, but it was a number of years before Zeise (1847) 

 isolated carotin from c/arrot roots in quantity sufficient for analysis. 

 Zeise discovered the ready solubility of the pigment in carbon disul- 

 fide with its characteristic blood red color, as well as the fact that 



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