PANTOTHENIC ACID 



al.^^ found that the pantoyl derivatives of a-alanine, ^-aminobutyric 

 acid, aspartic acid and lysine were inactive when tested microbio- 

 logically, although j3-pantoylaminobutyric acid was claimed by 

 Hoffmann-La Roche ^^ to have pantothenic acid activity. The pantoyl 

 derivatives of L-leucine ^^ and of lysine, leucine, valine and taurine ^^ 

 were reported to have no growth-promoting activity. 



a-Methyl-pantothenic acid (N-pantoyl-a-methyl-/S-alanine) had only 

 o-ooi to o-oooi of the potency of pantothenic acid for stimulating 

 growth and acid production in L. helveticus, L. arabinosus and S.faecalis 

 R, and 0-002 to 0-0003 of the activity of pantothenic acid in stimulating 

 the growth of the Gebriider-Mayer and Fleischmann strains of bakers' 

 yeast. ^^ It had a slight antagonistic effect towards pantothenic acid. 

 j8-Methyl pantothenic acid (/S-pantoylaminobutyric acid), however, 

 inhibited the growth of Streptobacterium plantarum (page 399) when 

 the ratio of methyl-pantothenic acid to pantothenic acid exceeded 

 200 : I ; the growth of yeast was not affected, although respiration 

 was greatly reduced. 



Several other pantoyl-amino acids have been shown to possess 

 inhibitory activity (see pages 398-400). 



Analogues Derived from Amino Alcohols and Amines 



So far consideration has been given only to analogues of panto- 

 thenic acid that contain a free carboxyl group, that is, to pantoyl- 

 amino acids and substances derived from them by changes in the 

 pantoyl portion of the molecule. A large number of substances have 

 been prepared and tested for pantothenic acid activity, how^ever, that 

 do not possess a free carboxyl group. The most important of these, 

 pantothenyl alcohol or panthenol : 



CH2OH . C(CH3)2 . CHOH . CO . NH . CHg . CHg . CHgOH 



was prepared by H. Pfaltz,^^ who reported that it was as effective as 

 pantothenic acid in preventing achromotrichia in black rats. Its 

 methyl homologue, 3-pantoylamino-biitanol-2, was only slightly 

 active, however, whilst 2-pantoylaminoethanol and y-pantoylbutyric 

 acid were quite inactive. Pantothenyl alcohol did not stimulate the 

 growth of bacteria, but was quite a strong inhibitor of bacterial 

 growth (page 400). None of the other compounds derived from 

 alcohols or amines stimulated bacterial growth and many had inhibi- 

 tory properties. 



In warm-blooded animals, panthenol was converted into panto- 

 thenic acid,^® more of which was excreted by humans following a dose 

 of panthenol than after administration of the same weight of panto- 

 thenic acid.2^" Panthenol had 90 % of the activity of pantothenic 

 acid, gram for gram, in chicks.^ ^^ 



396 



