388 ENZYMES 



\ 



is a pentahydric alcohol occurring in Adonis vernalis. Ac- 

 cording to Treboux,* it is converted by the plant into starch. 

 Adonitol has a sweet taste, and is used in bacteriological media. 

 Of recent years a number of dihydric alcohols of high mole- 

 cular weight have been found to occur in plants. They belong 

 to o!ifferent series whose general formulae are 



CnH n- 6 O 4 , CnH 2 n- 8 O 4 , and CnH 2 n~io^4' 



Trifolianol, C 21 H 34 O 2 (OH) 2 , isolated by Power and Sal- 

 way,f from red clover leaves, may be taken as an example 

 of the first group, while Bryonol, C 22 H 34 O 2 (OH) 2 , obtained 

 by Power and Moore j from Bryony root, and Calabarol, 

 C 23 H 34 O 2 (OH) 2 , isolated by Salway from Calabar beans, are 

 representatives of the second and third groups respectively. 



Of the polyhydric alcohols Inositol is of particular interest, 

 and may, therefore, receive more detailed consideration. 



INOSITOL. 



Inositol, which has the formula C 6 H 12 O 6 , is isomeric with 

 the hexoses, and, like these substances, has a sweet taste ; for 

 these reasons, it was at one time thought to be a true sugar 

 and was called muscle sugar owing to its occurring in muscle. 



Inositol is, however, not a carbohydrate at all but a 

 polyhydric alcohol derived from benzene and having the 

 constitution 



CHOH CHOH 



CHOH /CHOH 



\CHOH-CHOH 



Besides being found in muscle, inositol is of common oc- 

 currence in plants, in the leaves, especially when young, of 

 Viti s, Juglans, etc. ; in the roots and rhizomes of very many 

 plants ; in various seeds and fruits, e. g. Phaseolus, Pisum, and 

 other leguminous seeds, Vitis, various cereals, and oily seeds, 

 such as mustard. 



* Treboux: " Ber. deut. hot. Gesells.," 1909, 27, 428. 



f Power and Salway: " J. Chem. Soc., Lond.," 1910, 97, 249. 



I Power and Moore : id., 1911, 99, 943. 



Salway : id t> ign, 99, 2155. 



