PYRIDOXINE 



erroneously, referred to as " methoxy-pyridoxine ". Four moles of 

 this substance antagonised the growth-promoting effect of one mole 

 of pyridoxine in chicks. ^^ Unlike desoxypyridoxine, however, it 

 actually reduced the amount of xanthurenic acid and kynurenine 

 excreted by rats when given together with tryptophan, 22 whilst the 

 excretion of 4-pyridoxic acid was increased. Thus although " meth- 

 oxypyridoxine " has anti- vitamin activity for the chick it has vitamin 

 Bg activity for the rat,^ being apparently demethylated in this animal 

 to pyridoxine. " Methoxypyridoxine " produced symptoms of vita- 

 min Bg deficiency in chicks and dogs, although in dogs the symptoms 

 were less severe than with desoxypyridoxine, due presumably to partial 

 cleavage to pyridoxine. ^^ 



3-Hydroxy-4-hydroxymethyl-2-methyl-pyridine, 3-amino - 5 - amino- 

 methyl-4-ethoxymethyl-2-ethyl-pyridine and 3-hydroxy-2 : 4 : 5-tri- 

 methyl-pyridine (" didesoxypyridoxine ") were weak antagonists of 

 pyridoxine. 2^" 



Irradiation of pyridoxine, pyridoxal and pyridoxamine gave 

 products that inhibited the growth of Gram-negative aerobic bacteria 

 and, to a lesser extent, two strains of Gram-positive cocci. ^^ The 

 anti-bacterial activity was antagonised by certain amino acids, but 

 nothing is known about the chemical constitution of the inhibitory 

 substance. 



Pyridoxine was claimed to inhibit the activity of quinine and 

 mepacrine against Plasmodium lophurae infections in ducklings when 

 given in amounts several times greater than those required for the 

 nutrition of the ducklings. 2® This led McCasland et al^^ to attempt 

 the preparation of analogues of pyridoxine that might antagonise the 

 pyridoxine required by the parasites. Various pyrimidines were 

 synthesised, but 4-hydroxy-2-hydrox5nTLethyl-5-methyl-2 : 6-bis- 

 pyrimidine had no pyridoxine or anti-pyxidoxine activity for 5. 

 cerevisiae. 



References to Section 19 



1. K. Unna, Proc. Soc. Exp. Biol. Med., 1940, 43, 122. 



2. E. E. Snell, /. Amer. Chem. Soc, 1944, 66, 2082. 



3. E. F. Moller, Z. physiol. Chem., 1939, 260, 246 ; E. F. Moller, 



O. Frina, F. Jung and T. Moll, Naturwiss., 1939, 27, 228 ; E. F. 

 Moller, Angew. Chem., 1940, 63, 204. 



4. P. R. Burkholder, Amer. J. Bot., 1943, 30, 206. 



5. W. J. Robbins, ibid., 1942, 29, 241. 



6. S. A. Harris, /. Amer. Chem. Soc, 1940, 62, 3203. 



7. S. A. Harris, T. J. Webb, and K. Folkers, ibid., 3198. 



8. J. V. Scudi, W. A. Bastedo and T. J. Webb, Proc Soc. Exp. Biol. 



Med., 1940, 43, 122 ; /. Biol. Chem., 1940, 136, 399. 



9. S. A. Harris and A. N. Wilson, /. Amer. Chem. Soc, 1941, 63, 2526. 



