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).

1st Class
FL1:Aurone and Chalcone	FL2:Flavanone	FL3:Flavone
2nd Class FL1A Aurone FL1B Auronol FL1C Chalcone FL1D Dihydrochalcone	2nd Class FL2F Flavanone	2nd Class FL3F Flavone
FL4: Dihydroflavonol	FL5: Flavonol	FL6: Flavan
2nd Class FL4D Dihydroflavonol	2nd Class FL5F Flavonol	2nd Class FL6F Flavan FL63 Flavan 3-ol FL64 Flavan 4-ol FL6D Flavan 3,4-diol
FL7: Anthocyanin	FLI: Isoflavonoid	FLN: Neoflavonoid
2nd Class FL7A Anthocyanin FL7D 3-Desoxyanthocyanin	2nd Class FLIA Isoflavone FLIB Isoflavanone FLIC Isoflavan FLID Pterocarpane FLIE Coumestan FLIF Rotenoid FLIG Coumaranochromone FLIH 3-Arylcoumarin FLII 2-Arylbenzofuran FLIJ alpha-Methoxynbenzoin	2nd Class FLNA 4-Arylcoumarin FLNB 4-Arylchroman FLNC Dalbergiquinol FLND Dalbergione FLNE Neoflavene FLNF Coumarinic acid

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)