OCCURRENCE OF THE TOCOPHEROLS 797 



2. Occurrence of the Tocopherols (Vitamins E) 



{1) Distribution in Plant Tissues 



The various types of vitamin E are found almost exclusively in plants, 

 and only to a minimal degree in the animal organism. All green plants 

 which have been examined have been shown to contain demonstrable 

 amounts of the tocopherols. Although wheat germ oiP^ and other seed 

 germ oils'^^-^'^ are generally considered to have the highest concentration of 

 vitamins E, Dam and his colleagues^^ have brought forward some evidence 

 to indicate that the green leafy vegetables and rose hips may contain more 

 extractable tocopherol on a dry-weight basis than does wheat gerai.'*^ 

 Mason ^^ considers that the storage of these various vitamins E in the em- 

 bryo of the seed may be an indication that they act as stabilizers of fats 

 during the period of dormancy, or that they are present as a reserve to sup- 

 ply some special function in early development and growth. 



The vegetable fats are relatively the highest sources of the tocopherols 

 among the natural food products. The tocopherol content of some vege- 

 table fats is recorded in Table 1. /3-Tocopherol, which is not listed in the 

 table, is found chiefly in wheat-germ oil. 



The low content of vitamins E in olive oil and especially in coconut oil is 

 of considerable interest. In fact, Bacharach and others,^*-^^ on the basis of 

 earlier work, reported the total absence of vitamin E in olive oil and the 

 small content in peanut oil. Lettuce and alfalfa contain considerable 

 amounts of the vitamins, while oranges and bananas have a low content. ^^ 

 The lower plants, such as algae, fungi, liverworts (Hepaticae), mosses, ferns 

 and primitive seed plants, are not believed to contain vitamin E.^^ Schop- 

 fer and Blumer^^ have definitely proven the absence of these compounds in 

 one fungus, the saprophytic mold, Phycomyces. 



The tocopherols occur in free (unesterified) forms in the seed oils."-^* 

 Rye geiTn oil is reported^'' to contain as much as 1050 milligram per cent. 

 The proportion among the different tocopherols varies with different plants, 

 and it is not always constant in the same plant. Thus, while European 

 wheat germ oil contains principally /3-tocopherol, with smaller amounts of 

 the a-form, or about equal amounts^^ of the two types, the a-variety pre- 

 dominates in the American wheat berry, with a smaller quantity of 7- 

 tocopherol. California w^heat germ oil contains about twice as much of the 



51 H. S. Olcott, J. Biol. Chem., 107, 471-474 (1934). 



" H. M. Evans and G. O. Burr, Proc. Natl. Acad. Sci. U. S., 11, 334-341 (1925). 



5^ H. Dam, J. Glavind, I. Prange, and J. Ottesen, Kgl. Danske Videnskab. Selskab 

 Biol. Medd., 16, No. 7, 1-39 (1941). 



5^ A. L. Bacharach, E. AUchorne, and H. E. Glynn, Biochem. J., 31, 2287-2292 (1937). 



" H. L. Rosenberg, Chemistry and Physiology of the Vitamins, Interscience, New York, 

 1945. 



« W. H. Schopfer and S. Blumer, Z. Vilaminforsch., 0, 344-349 (1939). 



" W. Halden, Monatsh., 77, 197-205 (1947). 



*8 A. R. Moss and J. C. Drummond, Biochem. J., 32, 1953-1956 (1938). 



