Flavonoids, isoflavonoids and neoflavonoids are natural products derived from 2-phenylchromen-4-one
(flavone), 3-phenylchromen-4-one and 4-phenylcoumarin, respectively. Derivations include
reduction of the 2(3) carbon-carbon double bond (flavanones), reduction of the
keto group (flavanols), and hydroxylation at various positions.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1335