Chapter XI 



INOSITOL 



I. INTRODUCTION 



The discovery by E, Wildiers ^ of " bios ", the hypothetical substance 

 necessary for the growth of certain yeasts, and its resolution into a 

 number of individual factors, has already been discussed (page 404). 

 The first of these substances to be identified was bios I, which was 

 shown by E. V. Eastcott ^ to be identical with meso-inositol, one of 

 the eight stereo-isomers of hexahydroxycyclohexane. This substance 

 had been known since 1850 when it was discovered in muscle by 

 D. Scherer.3 It was shown to be a cyclic hexahydroxy-alcohol by 

 L. Maquenne * in 1887 and synthesised by H. Wieland and R. S. 

 Wishart ^ in 1914. 



Although inositol thus became the first member of the bios complex, 

 it was not recognised as a growth factor for animals until 1940, when 

 D. W. Woolley ^ showed that mice reared on a diet deficient in inositol 

 lost weight and became hairless. It was subsequently demonstrated 

 that mice and other species of animals showed other characteristic 

 symptoms besides alopecia when made inositol-deficient (see page 



572). 



Inositol was therefore added to the list of substances essential for 

 the growth of micro-organisms and higher animals and was regarded 

 by many workers as a member of the vitamin B complex. 



There have been some misgivings, however, about the inclusion 

 of inositol in the vitamin B complex, as the amount of inositol required 

 by animals and micro-organisms is very considerably greater than their 

 requirements for other members of the vitamin B complex. 



Similarly, the amounts of inositol present in many foodstuffs far 

 exceed their contents of other members of the complex. These con- 

 siderations suggest that inositol must play a different role in the 

 economy of living organisms from that of aneurine or nicotinic acid, for 

 example, and that it is a structural component of living tissue rather 

 than a catalyst of metabolic reactions. Indeed, inositol has some of 

 the characteristics of the amino-acids, many of which are also essential 

 for the growth of animals and micro-organisms. Inositol and choline 

 (page 582) may, in fact, be regarded as a link between the vitamins 

 and amino acids. 



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