356 INOSITOLS 



When fresh tea leaves were stored in the dark for 20 hours, the glucose 

 and sucrose contents decreased and the inositol content increased. ^^ In- 

 filtration of the leaves with glucose, fructose, sucrose, and mannose as 

 well as other glucosides also increased the inositol content of the leaves, 

 the glucosides being more effective than the free glucose. ^^' " Glucose-1- 

 phosphate likewise resulted in a more rapid synthesis of inositol than did 

 free glucose.^" All this work suggests, but in no way proves, that inositol 

 is synthesized from sugars in these plants. 



The observation^^ that the phloroglucinol content of tea leaves increased 

 during the infiltration of the leaves with sugar solutions was interpreted to 

 mean that m^/o-inositol is a precursor of this aromatic compound in the 

 tea leaves. This is in agreement with Fischer's suggestion^ that inositol 

 is an intermediate between the sugars and aromatic substances. Apparently, 

 in the tea leaves the reverse reaction — conversion of phloroglucinol to 

 inositol — does not take place, for infiltration of the leaves with phloro- 

 glucinol did not increase their inositol content. ^^ 



The possible interconversion of inositol and ascorbic acid has been sug- 

 gested,^^ following the observations that these are the only two vitamins 

 present in significant amounts in citrus fruits. No experimental evidence 

 for such a conversion has yet been presented. 



C. INOSITOL SYNTHESIS BY ANIMALS 



Rosenberger,-" in 1908, found that he could isolate inositol from rabbits 

 which had been allowed to stand for several days after being killed, al- 

 though he was unable to find inositol in freshly killed rabbits. He also 

 stated that he found an increase in the inositol content of beef muscle on 

 standing and postulated the presence in muscle of an "inositogenic sub- 

 stance." Winter-^ likewise reported an increase in the inositol content of 

 dog heart muscle on standing. Since both investigators used an alkaline 

 hydrolysis to liberate inositol, some doubt is cast on these observations, for 

 it is now known that inositol is somewhat alkali-labile. 



Woolley-^ found that young mice which were fed on an inositol -deficient 



1^ A. L. Kursanov, N. N. Kryukova, and E. Vyskrebentseva, Biokhimiya 13, 530 



(1948) [C. A. 43, 3070 (1949)]. 

 1^ A. L. Kursanov, M. Vorob'eva, and E. Vyskrebentseva, Doklady Akad. Nauk. 



S.S.S.R. 68, 737 (1949) [C. A. 44, 1568 (1950)]. 

 "A. L. Kursanov, Izvest. Akad. Nauk. S.S.S.R., Ser. Biol. 2, 44 (1951) [C. A. 45, 



7644 (1951)]. 

 ^^ A. L. Kursanov, E. Vyskrebentseva, and M. Vorob'eva, Doklady Akad. Nauk. 



S.S.S.R. 68, 893 (1949) '[C. A. 44, 1172 (1950)]. 



19 W. A. Krehl and G. R. Cowgill, Food Research 15, 179 (1950). 



20 F. Rosenberger, Z. Phijsiol. Chem. 56, 373 (1908). 



21 L. B. Winter, Biochem. J. (London) 28, 6 (1934). 



22 D. W. Woolley, /. Exptl. Med. 75, 277 (1942). 



