Chapter II A. 



DISTRIBUTION OF B VITAMINS 



Of the ten members or possible members of the B vitamin family 

 discussed in Chapter IA, four (inositol, nicotinic acid, choline, and 

 p-aminobenzoic acid) were well recognized chemicals long before vitamins 

 were discovered. The earlier information regarding these is therefore 

 presented briefly first. 



Inositol was known during the last century as a compound of wide 

 distribution having been found in the sprouts, leaves, fruits, seeds and 

 rhizomes of a considerable number of plants and in the blood, urine and 

 various organs and tissues of animals such as cattle, guinea pigs and dogs. 

 It was found also in fowls and cephalopods and in human urine. Early 

 materials used in the preparation of inositol from natural sources included 

 walnut leaves, mistletoe berries and beef lung or beef heart. The complete 

 stereochemical structure of the naturally occurring substance, however, 

 was not elucidated until 1942. 1 - 2 



Nicotinic acid has been known chemically for about 80 years as a 

 product formed by strong oxidation of nicotine. It was first isolated from 

 natural sources (rice polishings) by Suzuki, Shamimura and Odake 3 and 

 soon after Funk 4 isolated it from both yeast and rice polishings in his 

 attempt to concentrate the anti-beriberi vitamin. Its natural occurrence 

 was not, however, mentioned in the 4th edition of Beilstein (1935) . It was 

 only after its coenzymic and vitamin functions were known that its wide- 

 spread occurrence was recognized. 



Choline, first isolated as a hydrolytic product of a phosphatide fraction 

 in 1865, was originally called "neurin." It was found later to be wide- 

 spread in ergot, in mushrooms, in the germs of seeds and in other plant 

 tissues: leaves, fruits, flowers, rhizomes. In these plant sources it was said 

 to be partly free and partly combined in what are now called phospho- 

 lipides. It was also found in animal tissues: glandular tissues, brain, 

 blood, sperm, etc. If, as is commonly thought, lecithins and related 

 phospholipides are always present in living cells, the universal distribu- 

 tion of choline in combined form is evident. 



p-Aminobenzoic acid has been known chemically since the infancy of 

 synthetic organic chemistry, but knowledge of its natural occurrence dates 

 from its isolation from yeast in 1 940-41. 5 - G It was administered to dogs 



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