Citric Acid and Inositol 189 



INOSITOL 



Occurrence and distribution 



Inositol was first discovered in 1850 by Scherer, at Wiirzburg, 

 who isolated it from the mother-liquor remaining after the separa- 

 tion of creatine from beef meat, as a crystalline, colourless and dis- 

 tinctly sweet-tasting substance. He named it 'inosit' to underline its 

 origin from muscle, and showed that its composition and properties, 

 except for lack of reducing capacity are similar to those of a hexose. 

 In 1887 Maquenne proved that this non-reducing and optically- 

 inactive compound is not a sugar in the strict sense but a hexitol 

 derived from cjc/ohexane. In the years which followed, Bouveault 

 (1894) and others brought forward evidence for the existence of 

 several cyclitols derived from cjc/ohexane; since then it became 

 customary to define the compound from muscle as m^^oinositol, in 

 distinction to the other isomers. The configuration of meso'mosiioX 

 was finally established in 1942, by Dangschat in Fischer's laboratory, 

 and by Theodore Posternak, in Switzerland. 



H H 



1 I 



C C 



H / 1 I \ OH 



1/ OH 0H\| 



c c 



I V OH H / I 



I I 



H OH 



mesolnosiXoX 



Apart from muscle, inositol has also been isolated from urine 

 (Cloetta, 1856), and from green beans (Vohl, 1856). Later, several 

 plants were found to yield on extraction such very large amounts 

 of this cyclitol, that like citric acid, me^oinositol came to be 

 regarded generally as a typical plant constituent, a view strengthened 

 by the discovery of phytic acid (inositol hexaphosphate) in grain, 

 and lipositol (a monophosphoinositol-containing phosphatide) in 

 soya-bean. The interesting history of these and later developments 

 in the biochemistry of inositol will be found in the monograph by 



