FLAVONOIDS AND RELATED COMPOUNDS 



195 



and the glycoside mangiferin from roots of Mangifera indica: 



OH 



other naturally occurring benzophenones lack the heterocyclic oxygen ring of the xan- 

 thones but are otherwise similar. Maclurin from osage orange and fustic wood has been 

 used as a yellow dye. Various cotoin derivatives of coto bark have been used in medicine 

 as astringents. Hydroxybenzophenone derivatives have sometimes been grouped under 

 "condensed tannins". 



maclurin (Madura poDiifera) 



OH 



cotoin (Aniba coto) 



One example of the so-called bis-flavones is dracorubin from dragon's blood resin 

 of Dracaena draco: 



OCH, 



