CAROTENOIDS IN LAND PLANTS 



Table 1. — Leaf Carotenes 



(There is still some discrepancy concerning the m.p. of y-carotene {see Zechmeister 

 and Schroeder (3) for a discussion.) 



REFERENCES TO TABLE 1. 



1. Karrer, p., and Walker, O. (1933), Helv. Chim. Acta., 16, 641. 



2. Karrer, P. (1945), Vierteljahrsch. Naturforsch. Ges. Zurich, 90, 1. 



3. Zechmeister, L., and Schroeder, W. A. (1942), Arch. Biochem., 1, 231. 



4. PolgAr, a., and Zechmeister, L. (1942), y. Amer. Chem. Soc, 64, 1856. 



5. Deuel, H. J., jun., Johnston, C, Meserve, E. R., PolgAr, A., and Zechmeister, L. (1945), 



Arch. Biochem., 7, 247. 



6. BiCKOFF, E. M,, White, L. M., Bevenue, A., and Williams, K. T. (1948), J. Asm. Off. 



Agric. Chem., 31, 633. 



XANTHOPHYLLS 



Much of our knowledge of leaf xanthophylls is due to a series of 

 researches by Strain which he has reported in detail. "^ He has 

 not only confirmed the earlier findings of Kuhn, Winterstein and 

 Lederer ^ • that the predominating carotenoid is lutein (xanthophyll), 

 but has also isolated, by chromatography on magnesia, a number of 

 minor components. It should be noted at this point that the position 

 of the two hydroxyl groups in lutein are not completely fixed although 

 they are generally accepted as being at 3- and 3'-. 



Oxidation of lutein (xanthophyll) with KMnO* yields a mixture 

 1 : 1-dimethylsuccinic and dimethylmalonic acids but no geronic or 

 1 : 1-dimethylglutaric acids. «' This indicates that, as there is one 



CH, 



CHj 



\/ 

 c 



/\ 



CH2 



COOH 



COOH 



i : l-dimethylsuccinic 

 acid 



CH3 CH3 



\/ 



c 



/\ 



COOH COOH 



Dimeth/lmalonic 

 acid 



13 



