Fig. 2
From: Epigenetic activities of flavonoids in the prevention and treatment of cancer
Chemical structures of flavonoid subclasses. The six flavonid subclasses include flavan-3-ols, flavonols, flavones, flavanones, isoflavones, and anthocyanidins, which all feature a flavan backbone. The closely related chalcones (ring closure causes flavonoid formation) and flavonolignans (complex flavonoids consisting of a flavonoid covalently bound to a lignan) are displayed as well (grey box)