86 CAROTINOIDS AND RELATED PIGMENTS 



Carotinoids in Seeds and Grains 



The wide distribution of carotinoids in flowers and fruits, as re- 

 vealed in the foregoing paragraphs, naturally justifies the expectation 

 that the same pigments should be found in seeds and especially in the 

 grains of plants of the grass species where fruit and seed are, for 

 practical purposes, one and the same. 



Of the true seeds the plant biochemists who have studied pigments 

 naturally have been interested especially in the highly pigmented 

 endocarp or aril which characterizes a number of plants. Several 

 of these have been the object of investigation. 



Courchet (1888) recrystallized the ether extractable pigment of the 

 arils of Euonymous japonicus (Japanese Spindle-tree), Momordica 

 Balsamina (Balsam Apple) and Passiflora coerulea (Passion flower 

 plant). The red-orange rhombic shaped tablets obtained from the 

 aril of the Spindle-tree indicate the close relation of the pigment to 

 carotin, while the carmine colored needles which Courchet obtained 

 from the bright red arils of the other two plants were recognized by 

 him as being identical in form and color with those obtainable from 

 tomatoes and from the flesh of watermelons. It would appear that 

 the more orange colored endocarps owe their color to carotin (and 

 probably xanthophylls) while those of a more distinct red color are 

 pigmented by lycopin. This supposition is borne out by the observa- 

 tion of Schrotter-Kristelli (1895a), who found the orange color of the 

 aril of Afzelia Cuazensis to be due to carotin, dissolved in a thick 

 orange-yellow oil, from which he recovered and recrystallized the pig- 

 ment after saponification of the oil. The Toblers (1910a) and Duggar 

 (1913) have confirmed Courchet's observation that the red pigment 

 in the bright red aril of Momordica Balsamina is lycopin. Duggar has 

 observed also that the aril pigment of Momordica charantia is lyco- 

 pin, which fact has already been mentioned. Lubimenko (1914a) be- 

 lieves that the aril of Euonymous Japonicus owes its color to the same 

 pigment. 



There is less certainty regarding the character of the carotinoid in 

 the arils of some of the other plants. Tammes (1900) obtained caro- 

 tinoid color reactions and a Molisch microchemical crystallization of 

 the pigment in the aril of Euonymous latifolia Scop. (Spindle-tree), 

 which was substantiated completely by van Wisselingh (1915). Both 

 Kohl (1902) and van Wisselingh (1915) obtained positive carotinoid 

 reactions for the aril of Taxus baccata (Yew tree), but according to 



