Flavonols

Flavonols (with an "o") 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]

Contents

Flavonols

Flavonols
Name IUPAC name 5 6 7 8 2' 3' 4' 5' 6'
3-hydroxyflavone 3-hydroxy-2-phenylchromen-4-one H H H H H H H H H
Azaleatin 2-(3,4-dihydroxyphenyl)-3,7-dihydroxy-5-methoxychromen-4-one OCH3 H OH H H H OH OH H
Fisetin 3,3',4',7-tetrahydroxy-2-phenylchromen-4-one H H OH H H H OH OH H
Galangin 3,5,7-trihydroxy-2-phenylchromen-4-one OH H OH H H H H H H
Gossypetin 2-(3,4-dihydroxyphenyl)-3,5,7,8-tetrahydroxychromen-4-one OH H OH OH H OH OH H H
Kaempferide 3,5,7-trihydroxy-2-(4-methoxyphenyl)chromen-4-one OH H OH H H H OCH3 H H
Kaempferol 3,4',5,7-tetrahydroxy-2-phenylchromen-4-one OH H OH H H H OH H H
Isorhamnetin 3,5,7-trihydroxy-2-(4-hydroxy-3-methoxyphenyl)chromen-4-one OH H OH H H OCH3 OH H H
Morin 2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one OH H OH H OH H OH H H
Myricetin 3,3',4',5',5,7-hexahydroxy-2-phenylchromen-4-one OH H OH H H OH OH OH H
Natsudaidain 2-(3,4-dimethoxyphenyl)-3-hydroxy-5,6,7,8-tetramethoxychromen-4-one OCH3 OCH3 OCH3 OCH3 H H OCH3 OCH3 H
Pachypodol 5-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxychromen-4-one OH H OCH3 H H H OH OCH3 H
Quercetin 3,3',4',5,7-pentahydroxy-2-phenylchromen-4-one OH H OH H H OH OH H H
Rhamnazin 3,5-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-7-methoxychromen-4-one OH H OCH3 H H OCH3 OH H H
Rhamnetin 2-(3,4-dihydroxyphenyl)-3,5-dihydroxy-7-methoxychromen-4-one OH H OCH3 H H OH OH H H

Flavonols glycosides

Flavonols glycosides and acetylated glycosides
Name Aglycone 3 5 6 7 8 2' 3' 4' 5' 6'
Astragalin Kaempferol Glc
Azalein Azaleatin Rha
Hyperoside Quercetin Gal
Isoquercitin Quercetin Glc
Kaempferitrin Kaempferol Rha Rha
Myricitrin Myricetin Rha
Quercitrin Quercetin Rha
Robinin Kaempferol Robinose Rha
Rutin Quercetin Rutinose
Spiraeoside Quercetin Glc
Xanthorhamnin Rhamnetin trisaccharide
Amurensin Kaempferol Glc tert-amyl
Icariin Kaempferide Rha Glc tert-amyl
Troxerutin Quercetin Rutinose hydroxyethyl hydroxyethyl hydroxyethyl

Drug interactions

Flavonoid 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

References

  1. ^ a b Cermak R, Wolffram S (October 2006). "The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms". Curr. Drug Metab. 7 (7): 729–44. doi:10.2174/138920006778520570. PMID 17073577. http://www.bentham-direct.org/pages/content.php?CDM/2006/00000007/00000007/0004F.SGM. 
  2. ^ Tautomerism of flavonol glucosides: relevance to plant UV protection and flower colour, Gerald J. Smith and Kenneth R. Markham. Journal of Photochemistry and Photobiology A: Chemistry, Volume 118, Issue 2, 30 October 1998, Pages 99-105
  3. ^ Si D, Wang Y, Zhou YH, et al. (March 2009). "Mechanism of CYP2C9 inhibition by flavones and flavonols". Drug Metab. Dispos. 37 (3): 629–34. doi:10.1124/dmd.108.023416. PMID 19074529. http://dmd.aspetjournals.org/cgi/pmidlookup?view=long&pmid=19074529. 
Types of Flavonoids
Flavonoids
Isoflavonoids
Neoflavonoids
Aurones
Other categories
Flavonols and their conjugates
Backbone
Aglycones
3-Hydroxyflavone (synthetic) and derivatives
Flavonols
Aglycones
Conjugates
Glycosides of herbacetin
Rhodionin | Rhodiosin
Glycosides of kaempferol
Afzelin (Kaempferol 3-rhamnoside) | Astragalin | Kaempferitrin | Juglanin (Kaempferol 3-O-arabinoside) | Kaempferol 3-alpha-L-arabinopyranoside | Kaempferol 3-alpha-D-arabinopyranoside | Kaempferol 7-alpha-L-arabinoside | Kaempferol 3-O-beta-D-galactoside | Kaempferol 7-O-glucoside | Kaempferol 3-lathyroside | Kaempferol 4'-rhamnoside | Kaempferol 5-rhamnoside | Kaempferol 7-rhamnoside | Kaempferol 7-O-alpha-L-rhamnofuranoside | Kaempferol 3-xyloside | Kaempferol 7-xyloside | Robinin | Sophoraflavonoloside (Kaempferol 3-O-sophoroside)
Glycosides of myricetin
Myricetin 3-O-rutinoside | Myricetin-3-O-neohesperidoside | Myricitrin
Conjugates of quercetin
Sulfates
Quercetin 3-O-sulfate | Quercetin 3,3'-bissulfate | Quercetin 3,4'-bissulfate
Glycosides
CTN-986 | Guaijaverin (quercetin 3-O-arabinoside) | Heliosin (Quercetin 3-digalactoside) | Hyperoside | Isoquercitin | Miquelianin | Quercetin-3-sophorodide | Quercitrin | Rutin | Spiraeoside
O-Methylated flavonols
Aglycones
Glycosides
Azalein | Centaurein | Eupalin | Eupatolin | Jacein | Patulitrin | Tamarixetin 7-rutinoside | Xanthorhamnin
Derivative flavonols
Aglycones
Noricaritin | Dihydronoricaritin
Glycosides
Amurensin | Icariin | Phelloside | Dihydrophelloside | Rutin S
Pyranoflavonols
Aglycones
Furanoflavonols
Aglycones
Glycosides
Pongamoside A, B and C
Semisynthetic
Glycosides