512 THE TOCOPHEROLS 



alloxan-like substance (considered later), and the prevention of testicular 

 atrophy in the male rat^^ have also been suggested as possible methods of 

 bioassay of vitamin E. The interesting suggestion to use the transparent 

 crustacean Daphnia magna for rapid detection and evaluation of vitamin 

 E^" seems never to have been further developed. 



VI. Occurrence in Food 



HENRY A. MATTILL 



The distribution of the tocopherols is probably wider than that of any 

 other vitamin, certainly more extensive than that of the other fat-soluble 

 types. They occur as free alcohols, not as esters, and except for their con- 

 sequent rapid oxidation in experimental rations containing certain unsatu- 

 rated fats their discovery might have been long delayed. Before the develop- 

 ment of trustworthy chemical methods for the separate estimation of each 

 of the tocopherols, the application of the arduous bioassay had provided 

 much information on the occurrence of vitamin E in various plants and in 

 animal tissues. Subsequent chemical determinations have added many 

 items, ^ ' 2 most of which can be found in the usual food tables. The richest 

 dietary sources are the vegetable oils and cereal products containing them, 

 butter and margarine, eggs and liver, legumes and greens. 



In plant tissue the tocopherols usually accompany carotene or highly 

 unsaturated fatty acids (in seed oils),^ substances readily oxidized in air. 

 There appears to be a significant correlation between the amounts of linoleic 

 acid and tocopherol found in fats and oils.^ As was pointed out,^ this as- 

 sociation of tocopherol and unsaturated fatty acids in vegetable tissues 

 and the presence of relatively impermeable cellulose walls afford consider- 

 able protection against autoxidation, whereas in animal tissue there are 

 no barriers to the diffusion of oxygen. If there is likelihood of peroxidation 

 of the fats in animal tissue and if the tocopherols act as stabilizers, one 

 would expect to find a higher concentration of them in tissues of high fat 

 content. In the rat,^ except for the pituitary and suprarenals, this appears 

 to be true, but none of the many rat tissues examined is completely devoid 



63 M. L. Herraiz and J. C. Radice, Ann. N. Y. Acad. Set. 52, 88 (1949). 

 ■"> A. Viehoever and I. Cohen. Am. J. Pharm. 110. 297 (1938). 



1 M. L. Quaife, Ann. N. Y. Acad. Sci. 52, 300 (1949). 



2 P. L. Harris, M. L. Quaife, and W. J. Swanson, /. Nutritio/i 40, 367 (1950). 

 3E. M. Bradway and H. A. Mattill, J. Am. Chem. Soc. 56, 2405 (1934). 



* E. L. Hove and P. L. Harris, J. Am. Oil Chemists' Soc. 28, 405 (1951). 



* K. C. D. Hickman and P. L. Harris, Advances in Enzymol. 6, 469 (1946). 



