Flavonols
From Wikipedia
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"), another class of flavonoids (see catechin for this class).
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
| 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
| 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
- ↑ 1.0 1.1 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:. PMID 17073577. http://www.bentham-direct.org/pages/content.php?CDM/2006/00000007/00000007/0004F.SGM.
- ↑ 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
- ↑ 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:. PMID 19074529. http://dmd.aspetjournals.org/cgi/pmidlookup?view=long&pmid=19074529.
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