686 XI. VITAMINS E (tocopherols) 



creased amounts of the vitamin are given to rats five to seven months of 

 g^gg 24.25 Xhjs effect occurs late in adolescence, and appears later in the 

 female than in the male. Martin^^ was of the opinion that the antisterility 

 and growth-promoting effects of vitamin E are due to different factors; 

 he was able to effect a partial separation of the factors by fractional cry- 

 stallization of vitamin E concentrates. This suggestion would seem 

 plausible, in view of the demonstration by Adamstone'^ of the possible 

 relation of this vitamin to cell division, and especially since the multiple 

 nature of the group has become increasingly evident in recent years. 



Still another property which has played an important role in the in 

 vitro and in vivo action of A'itamin E is its antioxidant activity. Simmonds 

 et al.'^ noted that wheat germ oil prevented the destructive effect of ferrous 

 sulfate on vitamin A.-^ MattilP" observed that diets which produced ster- 

 ility were usually those subject to a rapid development of rancidity. The 

 question which was then raised was whether or not the antioxidant and 

 antisterility effect of wheat germ oil are to be ascribed to the same com- 

 pound. Olcott and Mattill'' answered this question in the negative by 

 fractionating the antisterility and antioxidant principles of wheat germ 

 oil with petroleum ether and 92% methyl alcohol. These investigators*^ 

 later reported that, whereas acetylation destroyed the antioxidant action 

 completely, it did not interfere with the effectiveness as an antisterility 

 agent. Moreover, Stern et al.^ and Olcott and Emerson*^ proved that the 

 antisterility activity and antioxidant action varied inversely in the several 

 tocopherols available to them. Thus, a-tocopherol exerted the greatest 

 antisterility effect, and 5-tocopherol was least effective in this respect, 

 while the antioxidant action of 5-tocopherol was greatest, and that of 

 a-tocopherol was poorest. 



The separation and identification of the tocopherols has been elucidated 

 by a brilHant series of investigations. As early as 1927, it was recognized 

 that vitamin E occurs in the non-saponifiable fraction of fats.^^ Olcott 



24 H. M. Evans, J. Nutrition, 1, 23-28 (1928). 



26 G. A. Emerson and H. M. Evans, J. Nutrition, 14, 169-178 (1937). 



2« G. J. Martin, J. Nutrition, IS, G79-685 (1937). 



2' F. B. Adamstone, Science, 80, 450 (1934). 



28 N. Simmonds, J. E. Becker, and E. V. McCollum, /. Am. Med. Assoc, 88, 1047- 

 1050(1927). 



29 J. H. Jones, J. Biol. Chem., 75, 139-146 (1927). 



3« H. A. Mattill, /. Am. Med. Assoc, 89, 1505-1508 (1927). 



31 H. S. Olcott and H. A. Mattill, •/. Biol. Chem., 93, 59-70 (1931). 



32 H. S. Olcott and H. A. Mattill, J. Biol. Chem., 104, 423-435 (1934). 



33 H. S. Olcott and O. H. Emerson, J. Am. Chem. Soc, 69, 1008-1009 (1937). 

 3" H. M. Evans and G. O. Burr, Mem. Univ. Calif., 8, 1-158 (1927). 



