^-AMINOBENZOIC ACID 



synthesised by bacteria in the gut. Apparently the symptoms were 

 more or less completely cured by the addition of folic acid to the diet.'^ 

 _/)-Aminobenzoic acid failed to cure the greying resulting from a de- 

 ficiency of pantothenic acid.^^ 



Grey hair has been claimed to be symptomatic not only of ^-amino- 

 benzoic acid deficiency, but also of pantothenic acid deficiency (see 

 page 365), biotin deficiency (see page 424), folic acid deficiency (see 

 page 487) and inositol deficiency (see page 572). It is possible that 

 ^-aminobenzoic acid is a chromotrichial factor because it is converted 

 into folic acid, which is especially effective in stumulating the growth 

 of the intestinal bacteria (see page 505), but such an explanation cannot 

 apply to other members of the vitamin B complex, which are obviously 

 not inter-convertible. The true explanation of the existence of 

 several chromotrichial factors must be that many members of the 

 vitamin B complex are capable of stimulating the growth of the 

 intestinal flora, when this has been depressed either by feeding a 

 purified diet or as the result of treatment with a sulphonamide, and 

 that once the intestinal bacteria have regained their full vigour, they 

 synthesise the factor necessary for the formation of melanin. 



Indirect confirmation of this hypothesis was provided by Coates 

 et al. P who found that refected rats (page 75) were entirely dependent 

 on the symbiotic microflora for their supply of essential growth factors 

 and were therefore particularly suitable for detecting interference 

 with the activity of these organisms by growth inhibitors. They 

 showed that sulphapyrazine, sulphathiazole, sulphaguanidine, sulpha- 

 suxidine and sulphathalidine reduced the excretion of aneurine and that 

 the addition of ^-aminobenzoic acid restored the excretion to normal. 



The effect of _/)-aminobenzoic acid on the intestinal flora also 

 accounts for its ability to cure a hypoprothrombinaemia produced in 

 young rats by feeding sulphasuxidine.^^ The _/)-aminobenzoic acid 

 stimulated the growth of the bacteria in the intestinal tract and these 

 then synthesised the vitamin K necessary to restore the blood-clotting 

 mechanism to normal. 



^-Aminobenzoic acid was not apparently necessary for growth in 

 the pig,^^ but it appeared to be essential for young trout. ^^ In its 

 absence these developed pale livers, 10 to 20 mg. per 100 g. of diet 

 being necessary to prevent this condition. 



References to Section 5 



1. S. Ansbacher, Science, 1941, 93, 164. 



2. G. J. Martin and S. Ansbacher, Proc. Soc. Exp. Biol. Med., 1941. 



48, 118. 



3. G. A. Emerson, ibid., 1941, 47, 448. 



4. G. J. Martin and S. Ansbacher, /. Biol. Chem., 1941, 138, 441. 



