GLUCOSIDES 81 



THE ALDEHYDE GLUCOSIDES 



Salinigrin, CisHieOy (glucose and ra-oxy benzaldehyde), is 

 found in the bark of one species of willow (Salix discolor). Its 

 isomer, known as helicin (glucose and o-oxy benzaldehyde, or 

 salicylic aldehyde), does not occur naturally in any plant, but is 

 easily produced artificially by the gentle oxidation of salicin. 

 Their relationships are shown on the following formulas; 



Salicin Helicin Salinigrin 



lCH 2 OH 



JOX 



)X 



Amygdalin, also contains a benzaldehyde group, but there is 

 linked with it a hydrocyanic acid group; hence, this glucoside 

 is usually classed with the cyanophoric glucosides (see page 86). 



THE ACID GLUCOSIDES 



The most common example of this group is gaultherin,Ci4Hi 8 O8, 

 which is found in the bark of the black birch and is a combination 

 of glucose with methyl salicylate. Both the glucoside itself and 

 the methyl salicylate (" oil of wintergreen ") which is derived 

 from it are used as remedies for rheumatism. 



Jalapin, C44Hs6Oi6 (glucose and jalapinic acid), and con- 

 volvulin, C54Hg6O27 (glucose +rhodeose+ con volvulinic acid), are 

 glucosides of very complex organic acids, found in jalap resin, 

 which are used in medicine as cathartics or purgatives. 



THE OXY-CUMARIN GLUCOSIDES 



Cumarin itself is widely distributed in plants. No glucoside 

 containing cumarin as such has yet been isolated; but several 

 glucosides of its oxy-derivatives are known. The following are 

 common ones: 



Skimmin, CisHieOg (glucose and skimmetin), is found in 

 Skimmia japonica; aesculin, CisHieOg (glucose and sesculetin), 

 is found in the bark of the horse-chestnut, dEsculus hippocastanum, 

 and its isomer, daphnin (glucose and daphnetin), in several species 



