HISTORK.'AL DKVIiLOPMENT G87 



and MattilP^'^^ observed that the vitamin could bo prepared in high con- 

 centration by vacuum distillation. Drummond and co-workers^* employed 

 chromatographic adsorption on Broekmann alumina columns for their 

 separation. Evans, Emerson and Emerson^ and Emerson et al/^^ prepared 

 esters of vitamin E with allophanic acid, and were able to separate these 

 into two pure crystalline products which had different vitamin E activity. 

 The more potent of these was called a-tocopherol, \vhile the second one 

 was later identified as jS-tocopherol.^ Todd, Bergel, Waldmann, and 

 \yQj.]^37,3s confirmed the data of Evans et al.;^ they also prepared a new 

 allophanate which they called /3-tocopheryl allophanate. This compound 

 melted at 143.5-144.5°C., and is apparently the same product separated 

 by Emerson and co-workers'^ in impure form. The term "tocopherol" 

 was employed because of its relation to reproduction and by virtue of the 

 fact that these compounds were proved to be alcohols.*^'^^ 



Emerson and co-workers- subsequently separated a third member of 

 the group from cottonseed oil, as an allophanate. This was called 7- 

 tocopherol. Its biologic activity (as an antisterility vitamin) was found 

 to be only one-third of that of a-tocopherol.- As already noted, 5-to- 

 copherol, which was prepared from soybean oil, was considered to have the 

 least antisterility action but the greatest antioxidant capacity of any of 

 the four tocopherols then known. ^ The separation of the remaining mem- 

 bers of the tocopherol group has been accomplished largely by the use of 

 specially devised chromatographic procedures. Brown and Blaxter""^ 

 and Bro^vn alone^^'^- employed the classical tocopherol purification se- 

 quence — extraction, saponification, and separation of the carotenoids 

 by column chromatography — as well as an additional step which involved 

 desterolation by freezing out from a methanol solution. As a result of this 

 procedure which was followed by the use of paper chromatographic meth- 

 ods/' Brown,'*'* and Eggitt and Ward,^''** demonstrated the presence of 

 a new tocopherol-like material in wheat, which Brown**'* considered to be 



35 J. C. Drummond, E. Singer, and R. J. MacWalter, Biochem. J., 29, 456-471 (1935). 



36 O. H. Emerson, G. A. Emerson, and H. M. Evans, Science, 83, 421 (1936). 



" A. R. Todd, F. Bergel, H. Waldmann, and T. S. Work, Nature, I40, 361-362 (1937). 

 M A. R. Todd, F. Bergel, H. Waldmann, and T. S. Work, Biochem. J., 31, 2247-2256 

 (1937). 



39 H. S. Olcott, J. Biol. Chem., 110, 695-701 (1935). 



« F. Brown and K. L. Blaxter, Chemistry & Industry, 1951, 633-634. 



^1 F. Brown, Biochem. J., 51, 237-239 (1952). 



^2 F. Brown, Biochem. .J., 52, 523-526 (1952). 



" P. W. R. Eggitt and L. D. Ward, J. Set. Food Ayr., 4, 176-179 (1953). 



^■t F. Brown, ./. Sci. Food Ayr., 4, 161-165 (1953). 



« P. W. R. Eggitt and L. D. Ward. J. Sci. Food Ayr., 6, 329-337 (1955). 



