CONSTITUENTS OF THE BIOSPHERE 



49 



H O 



^\ /^\ H H 



HC C CH C-C, 



I 1 II 2 II ^ ^ 



HC C C— C 3 CH 



% ^ \ X \ /^ 



C O C = C 



H H H 



Flavone 



H O 



-iJj^ \ / \ 



HC C CH. 



I 1 I! 2 I 



HC , ,C C — C 



H 



Flavanone 



H 

 C 



H 

 C 



3 CH 



C= c-^ 



H H 



H O 

 C C 



H H 

 HC" 'C ^C-OH C — C, 



HC^ C '^ C — C 3 CH 



c o c=c 



H H H 



Fl 



avonol 



These compounds are generally found in nature in the hydroxyl substituted 

 form, to give such derivatives as quercetin, a flavonol derivative which in 

 combination with glucose (as a glucoside) is to be found in many plants, or 

 hesperitin, a flavanone derivative which is present in the lemon as a 

 glucoside, hesperidin. 



OH o 



hoAA 



.OH 



4^ OH 



HO 



Quercetin 



OH 



\ 



CH, 



C 



JDH 



4>OCH3 



Hesperidin 



