Category:FL

FL: Flavonoid

Structural Characteristics

Flavonoid is a class of plant secondary metabolites that have two benzene rings (each called A-ring and B-ring) connected by a chain of three carbons (Figure 1).

The carbon chain, corresponding to the numbers 2,3,4 in Figure 1, is linked to a hydroxyl group in the A-ring to form the C-ring. The class of flavonoids are usually determined by the modification pattern of the C-ring (Table 1).

names	structure	class	description
Aurones and Chalcones	100px	FL1	The C-ring is absent (chalcones) or a 5-member ring (aurones).
Flavanone	100px	FL2
Flavone	100px	FL3
Dihydroflavonol	100px	FL4	Because many flavonols (FL5) are hydroxylated at their position 3, they form a different category in our classification.
Flavonol	100px	FL5
Flavan	100px	FL6
Anthocyanin	100px	FL7
Isoflavonoid	100px	FLI
Neoflavonoid	70px	FLN

Biosynthesis

Flavonoid is synthesized through the phenylpropanoid-acetate pathway in all higher plants. It is responsible for many biological activities including pigments, anti-oxidative or anti-allergic agents, and signaling elements in nodule formation. Some of them are quite familiar in our daily life.

Familiar examples. anthocyanin (blueberry), isoflavone (soybean), rutin (soba noodle), catechin (tea), flavan-diol (tea), naringeninchalcone (tomato), polyphenol (wine, cacao)