3O0 TANNINS 



also related to the above parent substance triphenylpropane, 

 or more closely to Chalkone, namely eriodictyol, hesperetin 

 and phloretin : — ■ 



_CO— CH=CH- 



Chalkone 

 OH .OH 



HO— ^ ^— CO— CH^CH— < ^— OH 



OH 



Eriodictyol, CjjHigOg 



OH OH 



-OCHo 



Hesperetin 

 OH 



-o 



HO— <r '>_CO— CH2— CH2— < >OH 



in 



Phloretin 



Phloretin, which combined with glucose, forms the gluco- 

 side phloridzin ; the close relationship between this substance 

 and the flavonol apigenin is also apparent from the formula 

 given below : — 



O 



HO— 



C-< >0H 



It is worthy of note that quercetin, C15H10O7, cy- 

 anidin, C15H12O7, eriodictyol, C15H12O6, and gambier catechin, 

 C15H14O6,, form a series of gradually increasing hydrogen and 

 decreasing oxygen content. 



