Quercetin

Source: Wikipedia, the free encyclopedia.
Quercetin
Skeletal formula of quercetin
Ball-and-stick model of the quercetin molecule
Names
Pronunciation /ˈkwɜːrsɪtɪn/
IUPAC name
3,3′,4′,5,7-Pentahydroxyflavone
Systematic IUPAC name
2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-1-benzopyran-4-one
Other names
5,7,3′,4′-
flavon-3-ol
, Sophoretin, Meletin, Quercetine, Xanthaurine, Quercetol, Quercitin, Quertine, Flavin meletin
Identifiers
3D model (
JSmol
)
317313
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.003.807 Edit this at Wikidata
EC Number
  • 204-187-1
579210
IUPHAR/BPS
KEGG
UNII
UN number 2811
  • InChI=1S/C15H10O7/c16-7-4-10(19)12-11(5-7)22-15(14(21)13(12)20)6-1-2-8(17)9(18)3-6/h1-5,16-19,21H checkY
    Key: REFJWTPEDVJJIY-UHFFFAOYSA-N checkY
  • InChI=1/C15H10O7/c16-7-4-10(19)12-11(5-7)22-15(14(21)13(12)20)6-1-2-8(17)9(18)3-6/h1-5,16-19,21H
    Key: REFJWTPEDVJJIY-UHFFFAOYAW
SMILES
  • O=C1c3c(O/C(=C1/O)c2ccc(O)c(O)c2)cc(O)cc3O
Properties
C15H10O7
Molar mass 302.236 g/mol
Appearance yellow crystalline powder[1]
Density 1.799 g/cm3
Melting point 316 °C (601 °F; 589 K)
Practically insoluble in water; soluble in aqueous alkaline solutions[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)
UV visible spectrum of quercetin, with lambda max at 369 nm

Quercetin is a plant

bitter flavor and is used as an ingredient in dietary supplements
, beverages, and foods.

Occurrence

Quercetin is a

Quercus.[4][5] It is a naturally occurring polar auxin transport inhibitor.[6]

Quercetin is one of the most abundant dietary flavonoids,

mg.[7]

Foods Quercetin,
mg / 100 g
capers
, raw		 234[3]
capers
, canned		 173[3]
lovage leaves, raw 170[3]
dock like sorrel 86[3]
radish leaves 70[3]
carob fiber 58[3]
dill weed, fresh 55[3]
coriander 53[3]
yellow wax pepper, raw 51[3]
fennel leaves 49[3]
onion, red 32[3]
radicchio 32[3]
watercress 30[3]
kale 23[3]
chokeberry
 19[3]
bog blueberry 18[3]
buckwheat seeds 15[3]
cranberry 15[3]
lingonberry
 13[3]
plums, black 12[3]

In red onions, higher concentrations of quercetin occur in the outermost rings and in the part closest to the root, the latter being the part of the plant with the highest concentration.[8] One study found that organically grown tomatoes had 79% more quercetin than non-organically grown fruit.[9] Quercetin is present in various kinds of honey from different plant sources.[10]

Biosynthesis

In plants,

4-coumaroyl-CoA-ligase.[11] One molecule of 4-coumaroyl-CoA is added to three molecules of malonyl-CoA to form tetrahydroxychalcone using 7,2′-dihydroxy-4′-methoxyisoflavanol synthase. Tetrahydroxychalcone is then converted into naringenin using chalcone isomerase
.

Naringenin is converted into

dihydroquercetin with flavanone 3-hydroxylase, which is then converted into quercetin using flavonol synthase.[11]

Glycosides

3-O-Glycosides of quercetin

Quercetin is the

isoquercitin is the 3-O-glucoside and spiraeoside is the 4′-O-glucoside. CTN-986 is a quercetin derivative found in cottonseeds and cottonseed oil. Miquelianin is the quercetin 3-O-β-D-glucuronopyranoside.[12]

Several taxifolin (also known as dihydroquercetin) glycosides also exist. Isoquercetin is the 3-O-glucoside of quercetin.

Rutin degradation pathway

The enzyme

hydrolyzes the glycoside quercitrin to release quercetin and L-rhamnose. It is an enzyme in the rutin catabolic pathway.[14]

Pharmacology

Pharmacokinetics

The

colonic fermentation.[2] Whereas quercetin has been shown to be a potent anti-inflammatory compound in a variety of in vitro and in vivo bioassay models, oral quercetin in human subjects has not exhibited the desired effects.[20] Because of low solubility and poor bioavailability of quercetin, derivatives have been synthesized to overcome these challenges and enhance its biological activity, leading to compounds with improved properties for possible therapeutic applications.[21]

Metabolism

Quercetin is rapidly metabolized (via glucuronidation) after the ingestion of quercetin foods or supplements.[22] Five metabolites (quercetin glucuronides) have been found in human plasma after quercetin ingestion.[23][22] Taken together, the quercetin glucuronides have a half-life around 11–12 hours.[22]

In rats, quercetin did not undergo any significant

quercetin-3-glucuronide, 3'-methylquercetin-3-glucuronide, and quercetin-3'-sulfate.[24] A methyl metabolite of quercetin has been shown in vitro to be more effective than quercetin at inhibiting lipopolysaccharide-activated macrophages.[18]

Compared to other flavonoids, quercetin is one of the most effective inducers of the phase II detoxification enzymes.[25]

In vitro studies show that quercetin is a strong inhibitor of the cytochrome P450 enzymes CYP3A4 and CYP2C19 and a moderate inhibitor of CYP2D6.[26][27] Drugs that are metabolized by these pathways may have increased effect. An in vivo study found that quercetin supplementation slows the metabolism of caffeine to a statistically significant extent in a particular genetic subpopulation, but in absolute terms the effect was almost negligible.[28]

Food safety

In 2010, the U. S. Food and Drug Administration acknowledged high-purity quercetin as generally recognized as safe for use as an ingredient in various specified food categories at levels up to 500 mg per serving.[29]

Health claims

Quercetin has been studied in

clinical trials.[2][30][31][32] While supplements have been promoted for the treatment of cancer and various other diseases,[2] there is no high-quality evidence that quercetin (via supplements or in food) is useful to treat cancer[33] or any other disease.[2][34]

The US Food and Drug Administration has issued warning letters to several manufacturers advertising on their product labels and websites that quercetin product(s) can be used to treat diseases.[35][36] The FDA regards such quercetin advertising and products as unapproved – with unauthorized health claims concerning the anti-disease products – as defined by "sections 201(g)(1)(B) and/or 201 (g)(1)(C) of the Act [21 U.S.C. § 321(g)(1)(B) and/or 21 U.S.C. § 321(g)(1)(C)] because they are intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease",[35][36] conditions not met by the manufacturers.

Safety

Little research has been conducted into the safety of quercetin supplementation in humans, and the results are insufficient to give confidence that the practice is safe. In particular, a lack of safety information exists on the effect of quercetin supplementation for pregnant women, breastfeeding women, children, and adolescents. The hormonal effects of quercetin found in animal studies raise the suspicion of a parallel effect in humans, particularly in respect of estrogen-dependent tumors.[37]

Quercetin supplementation can interfere with the effects of medications. The precise nature of this interaction is known for some common medicines, but for many, it is not.[37]

See also

References

  1. ^ a b c "Quercetin dihydrate safety sheet". Archived from the original on September 16, 2011.
  2. ^ a b c d e f g h i j "Flavonoids". Micronutrient Information Center, Linus Pauling Institute, Oregon State University, Corvallis, OR. November 2015. Retrieved 1 April 2018.
  3. ^ a b c d e f g h i j k l m n o p q r s t u v "USDA Database for the Flavonoid Content of Selected Foods, Release 3" (PDF). U.S. Department of Agriculture. 2011.
  4. ^ "Quercetin". Merriam-Webster. 29 November 2023.
  5. ^ "Quercetin (biochemistry)". Encyclopædia Britannica.
  6. PMID 12237347
    .
  7. PMID 8847003
    .
  8. PMID 17997520
    .
  9. PMID 17590007
    .
  10. S2CID 24796542
    .
  11. ^
    PMID 11402179
    .
  12. S2CID 260253046
    .
  13. ^ "Information on EC 3.2.1.66 - quercitrinase". BRENDA (BRaunschweig ENzyme DAtabase). Helmholtz Centre for Infection Research.
  14. S2CID 30101803
    .
  15. ^
    S2CID 23812714
    .
  16. PMID 15019969
    .
  17. PMID 21779561
    .
  18. ^
    S2CID 58651581
    .
  19. ^
    PMID 31557798
    .
  20. PMID 34248976
    .
  21. S2CID 245485982
    .
  22. ^
    PMID 10363620. Archived from the original
    (PDF) on 2017-05-17. Retrieved 2016-01-01.
  23. PMID 11334336
    .
  24. ^
    ISBN 0-8247-4023-8
    .
  25. PMID 21277359
    .
  26. PMID 29491651.{{cite journal}}: CS1 maint: DOI inactive as of November 2024 (link
    )
  27. S2CID 41563915
    .
  28. PMID 25025048
    .
  29. ^ "GRN No. 341 (Quercetin)". US Food and Drug Administration. 22 November 2010. Retrieved 27 October 2021.
  30. PMID 25845380
    .
  31. ^ Gross P (March 1, 2009), New Roles for Polyphenols. A 3-Part Report on Current Regulations & the State of Science, Nutraceuticals World
  32. PMID 25323953
    .
  33. ISBN 9780944235713
    .
  34. doi:10.2903/j.efsa.2011.2067
    . Retrieved 24 September 2014.
  35. ^ a b King JL (2 March 2017). "Warning Letter to Cape Fear Naturals". Inspections, Compliance, Enforcement, and Criminal Investigations, US Food and Drug Administration. Retrieved 29 November 2018.
  36. ^ a b Pace R (17 April 2017). "Warning Letter to DoctorVicks.com". Inspections, Compliance, Enforcement, and Criminal Investigations, US Food and Drug Administration. Retrieved 29 November 2018.
  37. ^
    S2CID 24772872
    .
  • Media related to Quercetin at Wikimedia Commons
Retrieved from "https://en.wikipedia.org/w/index.php?title=Quercetin&oldid=1285813595"