Flavonols

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Not to be confused with Flavanols.
Backbone of a flavonol, substituent numbers are indicated.

Flavonols are a class of flavonoids that have the 3-hydroxyflavone backbone (IUPAC name : 3-hydroxy-2-phenylchromen-4-one). Their diversity stems from the different positions the phenolic -OH groups. They are distinct from flavanols (with an "a", like catechin), another class of flavonoids.

Flavonols are present in a wide variety of fruits and vegetables. In Western populations, estimated daily intake is in the range of 20–50 mg per day for flavonols. Individual intake varies depending on the type of diet consumed.[1]

The phenomenon of dual fluorescence (due to excited state intramolecular proton transfer or ESIPT) is induced by tautomerism of flavonols (and glucosides) and could contribute to plant UV protection and flower colour.[2]

Flavonols[edit]

Flavonols
NameIUPAC name56782'3'4'5'6'
3-hydroxyflavone3-hydroxy-2-phenylchromen-4-oneHHHHHHHHH
Azaleatin2-(3,4-dihydroxyphenyl)-3,7-dihydroxy-5-methoxychromen-4-oneOCH3HOHHHHOHOHH
Fisetin3,3',4',7-tetrahydroxy-2-phenylchromen-4-oneHHOHHHHOHOHH
Galangin3,5,7-trihydroxy-2-phenylchromen-4-oneOHHOHHHHHHH
Gossypetin2-(3,4-dihydroxyphenyl)-3,5,7,8-tetrahydroxychromen-4-oneOHHOHOHHOHOHHH
Kaempferide3,5,7-trihydroxy-2-(4-methoxyphenyl)chromen-4-oneOHHOHHHHOCH3HH
Kaempferol3,4',5,7-tetrahydroxy-2-phenylchromen-4-oneOHHOHHHHOHHH
Isorhamnetin3,5,7-trihydroxy-2-(4-hydroxy-3-methoxyphenyl)chromen-4-oneOHHOHHHOCH3OHHH
Morin2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-oneOHHOHHOHHOHHH
Myricetin3,3',4',5',5,7-hexahydroxy-2-phenylchromen-4-oneOHHOHHHOHOHOHH
Natsudaidain2-(3,4-dimethoxyphenyl)-3-hydroxy-5,6,7,8-tetramethoxychromen-4-oneOCH3OCH3OCH3OCH3HHOCH3OCH3H
Pachypodol5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxychromen-4-oneOHHOCH3HHHOHOCH3H
Quercetin3,3',4',5,7-pentahydroxy-2-phenylchromen-4-oneOHHOHHHOHOHHH
Rhamnazin3,5-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-7-methoxychromen-4-oneOHHOCH3HHOCH3OHHH
Rhamnetin2-(3,4-dihydroxyphenyl)-3,5-dihydroxy-7-methoxychromen-4-oneOHHOCH3HHOHOHHH

Flavonols glycosides[edit]

Flavonols glycosides and acetylated glycosides
NameAglycone356782'3'4'5'6'
AstragalinKaempferolGlc
AzaleinAzaleatinRha
HyperosideQuercetinGal
IsoquercitinQuercetinGlc
KaempferitrinKaempferolRhaRha
MyricitrinMyricetinRha
QuercitrinQuercetinRha
RobininKaempferolRobinoseRha
RutinQuercetinRutinose
SpiraeosideQuercetinGlc
XanthorhamninRhamnetintrisaccharide
AmurensinKaempferolGlctert-amyl
IcariinKaempferideRhaGlctert-amyl
TroxerutinQuercetinRutinosehydroxyethylhydroxyethylhydroxyethyl

Drug interactions[edit]

Flavonoids have effects on CYP (P450) activity. Flavonols are inhibitor of CYP2C9 [3] and CYP3A4,[1] which are enzymes that metabolize most drugs in the body.

See also[edit]

References[edit]