Flavonols: Difference between revisions

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Flavonols are present in a wide variety of fruits and vegetables. In Western populations, estimated daily intake is in the range of 20–50&nbsp;mg per day for flavonols. Individual intake varies depending on the type of diet consumed.<ref name=Cermak06>{{cite journal |vauthors=Cermak R, Wolffram S |title=The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms |journal=Curr. Drug Metab. |volume=7 |issue=7 |pages=729–44 |date=October 2006 |pmid=17073577 |doi= 10.2174/138920006778520570|url=http://www.bentham-direct.org/pages/content.php?CDM/2006/00000007/00000007/0004F.SGM}}</ref>
Flavonols are present in a wide variety of fruits and vegetables. In Western populations, estimated daily intake is in the range of 20–50&nbsp;mg per day for flavonols. Individual intake varies depending on the type of diet consumed.<ref name=Cermak06>{{cite journal |vauthors=Cermak R, Wolffram S |title=The potential of flavonoids to influence drug metabolism and pharmacokinetics by local gastrointestinal mechanisms |journal=Curr. Drug Metab. |volume=7 |issue=7 |pages=729–44 |date=October 2006 |pmid=17073577 |doi= 10.2174/138920006778520570|url=http://www.bentham-direct.org/pages/content.php?CDM/2006/00000007/00000007/0004F.SGM}}</ref>


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]].<ref> {{cite journal | last1 = Smith | first1 = Gerald J. | last2 = Markham | first2 = Kenneth R. | year = 1998 | title = Tautomerism of flavonol glucosides: relevance to plant UV protection and flower colour | url = | journal = Journal of Photochemistry and Photobiology A: Chemistry | volume = 118 | issue = 2| pages = 99–105 }}</ref>
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]].<ref> {{cite journal | last1 = Smith | first1 = Gerald J. | last2 = Markham | first2 = Kenneth R. | year = 1998 | title = Tautomerism of flavonol glucosides: relevance to plant UV protection and flower colour | url = | journal = Journal of Photochemistry and Photobiology A: Chemistry | volume = 118 | issue = 2| pages = 99–105 | doi=10.1016/s1010-6030(98)00354-2}}</ref>


Besides being a subclass of [[Flavonoids#Research|flavonoids (health effects)]], flavonols are suggested by a study of cranberry juice to play a role along with [[proanthocyanidin]]s, in the juice's ability to block bacterial adhesion, demonstrated by the compressing the [[Fimbria (bacteriology)|fimbria]] of ''E. coli'' bacteria in the urinary tract so as to greatly reduce the ability of those bacteria to stay put and initiate an infection.<ref>http://medicalxpress.com/news/2016-07-juicy-news-cranberries.html</ref> Flavonol aglycones in plants are potent antioxidants that serve to protect the plant from reactive oxygen species (ROS).<ref>{{Cite journal|title=Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids.|last=Nakabayashi R1, Yonekura-Sakakibara K, Urano K, Suzuki M, Yamada Y, Nishizawa T, Matsuda F, Kojima M, Sakakibara H, Shinozaki K, Michael AJ, Tohge T, Yamazaki M, Saito K. | pmid=24274116 | doi=10.1111/tpj.12388|volume=77|issue=3|pmc=4282528|journal=Plant J|pages=367-79}}</ref>
Besides being a subclass of [[Flavonoids#Research|flavonoids (health effects)]], flavonols are suggested by a study of cranberry juice to play a role along with [[proanthocyanidin]]s, in the juice's ability to block bacterial adhesion, demonstrated by the compressing the [[Fimbria (bacteriology)|fimbria]] of ''E. coli'' bacteria in the urinary tract so as to greatly reduce the ability of those bacteria to stay put and initiate an infection.<ref>http://medicalxpress.com/news/2016-07-juicy-news-cranberries.html</ref> Flavonol aglycones in plants are potent antioxidants that serve to protect the plant from reactive oxygen species (ROS).<ref>{{Cite journal|title=Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids.|last=Nakabayashi R1, Yonekura-Sakakibara K, Urano K, Suzuki M, Yamada Y, Nishizawa T, Matsuda F, Kojima M, Sakakibara H, Shinozaki K, Michael AJ, Tohge T, Yamazaki M, Saito K. | pmid=24274116 | doi=10.1111/tpj.12388|volume=77|issue=3|pmc=4282528|journal=Plant J|pages=367-79}}</ref>

Revision as of 14:40, 18 December 2016

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 "a") such as 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]

Besides being a subclass of flavonoids (health effects), flavonols are suggested by a study of cranberry juice to play a role along with proanthocyanidins, in the juice's ability to block bacterial adhesion, demonstrated by the compressing the fimbria of E. coli bacteria in the urinary tract so as to greatly reduce the ability of those bacteria to stay put and initiate an infection.[3] Flavonol aglycones in plants are potent antioxidants that serve to protect the plant from reactive oxygen species (ROS).[4]

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 OCH3 OH H 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

Flavonol 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

Flavonoids have effects on CYP (P450) activity. Flavonols are inhibitor of CYP2C9 [5] 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.
  2. ^ Smith, Gerald J.; Markham, Kenneth R. (1998). "Tautomerism of flavonol glucosides: relevance to plant UV protection and flower colour". Journal of Photochemistry and Photobiology A: Chemistry. 118 (2): 99–105. doi:10.1016/s1010-6030(98)00354-2.
  3. ^ http://medicalxpress.com/news/2016-07-juicy-news-cranberries.html
  4. ^ Nakabayashi R1, Yonekura-Sakakibara K, Urano K, Suzuki M, Yamada Y, Nishizawa T, Matsuda F, Kojima M, Sakakibara H, Shinozaki K, Michael AJ, Tohge T, Yamazaki M, Saito K. "Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids". Plant J. 77 (3): 367–79. doi:10.1111/tpj.12388. PMC 4282528. PMID 24274116.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  5. ^ 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.
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