• Source: Flavonoid biosynthesis

Flavonoids are synthesized by the phenylpropanoid metabolic pathway in which the amino acid phenylalanine is used to produce 4-coumaroyl-CoA. This can be combined with malonyl-CoA to yield the true backbone of flavonoids, a group of compounds called chalcones, which contain two phenyl rings. Conjugate ring-closure of chalcones results in the familiar form of flavonoids, the three-ringed structure of a flavone. The metabolic pathway continues through a series of enzymatic modifications to yield flavanones → dihydroflavonols → anthocyanins. Along this pathway, many products can be formed, including the flavonols, flavan-3-ols, proanthocyanidins (tannins) and a host of other various polyphenolics.

Flavanoids can possess chiral carbons. Methods of analysis should take this element into account especially regarding bioactivity or enzyme stereospecificity.




Enzymes


The biosynthesis of flavonoids involves several enzymes.

Anthocyanidin reductase
Chalcone isomerase
Dihydrokaempferol 4-reductase
Flavone synthase
Flavonoid 3'-monooxygenase
Flavonol synthase
Flavanone 3-dioxygenase
Flavanone 4-reductase
Leucoanthocyanidin reductase
Leucocyanidin oxygenase
Naringenin-chalcone synthase




= Methylation

=
Apigenin 4'-O-methyltransferase
Luteolin O-methyltransferase
Quercetin 3-O-methyltransferase




= Glycosylation

=
Anthocyanidin 3-O-glucosyltransferase
Flavone 7-O-beta-glucosyltransferase
Flavone apiosyltransferase
Flavonol-3-O-glucoside L-rhamnosyltransferase
Flavonol 3-O-glucosyltransferase




= Further acetylations

=
Isoflavone-7-O-beta-glucoside 6"-O-malonyltransferase




References

Kata Kunci Pencarian:

• Kaempferol
• Antosianin
• Kesumba keling
• Hesperidin
• Medicago
• Pigmen hayati
• Flavonoid biosynthesis
• Flavonoid
• Fisetin
• Strawberry
• Isoflavonoid
• Chalcone synthase
• Flavan-3-ol
• Quercetin
• Catechin
• Flavanone 4-reductase