CHAPTER VI 

 GLUCOSIDES 



STRICTLY speaking, the term glucoside should be applied only 

 to such compounds as contain glucose as the characteristic basic 

 group. But in common usage, it refers to any compound which, 

 when hydrolyzed, yields a sugar as one of the products of the 

 hydrolysis. In all the natural glucosides which occur in plant 

 tissues, the other organic constituent, which is represented by the 

 R in the formula for glucosides (R- C 6 HnO 5 , or R- (CHOH) 5 CHO) 

 is some aromatic group, or closed-ring benzene derivative.* The 

 different organic constituents of glucosides are of a great variety 

 of types, such as phenols, alcohols, aldehydes, acids, oxyflavone 

 derivatives, mustard oils, etc. It is noteworthy, however, that no 

 nitrogenous groups of the protein type have been found combined 

 with sugars in glucosides. 



Some glucosides contain more than one saccnaride group, possi- 

 bly as di- or trisaccharides. Under proper conditions of hydroly- 

 sis, one or more of the saccharide groups can be removed from such 

 compounds, resulting in glucosides of simpler structure. 



H 

 C 



HC CH 



* The structural formula for benzene, C 6 H 6 , I II is one which it is 



HC CH 



Y 



H 



difficult and inconvenient to reproduce in type. On that account, it is 



A 



customary to indicate this formula by a plane hexagon, thus 



v 



It is understood, in all such cases, that the figure represents six carbon atoms 

 arranged in a closed ring, with alternate double and single bonds, and with a 

 hydrogen atom attached to each carbon. The printing of some other group 

 as OH, CH 3 , adjacent to an angle of the hexagon means that this group 

 replaces the H atom in the compound which is being illustrated. 



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