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What is it?

Quercetin is a plant pigment (flavonoid). It's found in many plants and foods, such as red wine, onions, green tea, apples, and berries.

Quercetin has antioxidant and anti-inflammatory effects that might help reduce swelling, kill cancer cells, control blood sugar, and help prevent heart disease.

Quercetin is most commonly used for conditions of the heart and blood vessels and to prevent cancer. It is also used for arthritis, bladder infections, and diabetes, but there is no strong scientific evidence to support most of these uses. There is also no good evidence to support using quercetin for COVID-19.

How effective is it?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for QUERCETIN are as follows:

Possibly ineffective for...

  • Athletic performance. Taking quercetin by mouth before exercise doesn't decrease fatigue or improve exercise ability.
There is interest in using quercetin for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.

Is it safe?

When taken by mouth: Quercetin is possibly safe for most people when used short-term. Quercetin has been safely used in doses up to 1 gram daily for 12 weeks. It's not known if long-term use or higher doses are safe.

When applied to the skin: There isn't enough reliable information to know if quercetin is safe or what the side effects might be.

Special precautions & warnings:

Pregnancy and breast-feeding: There isn't enough reliable information to know if quercetin is safe to use when pregnant or breast-feeding. Stay on the safe side and avoid use.

Kidney problems: Quercetin might make kidney problems worse. Don't use quercetin if you have kidney problems.

Are there interactions with medications?

Be cautious with this combination.
Antibiotics (Quinolone antibiotics)
Some scientists think that taking quercetin along with certain antibiotics, called quinolone antibiotics, might decrease the effects of these antibiotics. But it's too soon to know if this is a big concern.
Cyclosporine (Neoral, Sandimmune)
Quercetin might decrease how quickly the body breaks down cyclosporine. Taking quercetin with cyclosporine might increase the effects and side effects of cyclosporine.
Diclofenac (Voltaren, others)
Quercetin might decrease how quickly the body breaks down diclofenac. Taking quercetin with diclofenac might increase the effects and side effects of diclofenac.
Losartan (Cozaar)
Quercetin might change how the body absorbs and breaks down losartan. Taking quercetin with losartan might change the effects and side effects of losartan.
Medications changed by the liver (Cytochrome P450 2C8 (CYP2C8) substrates)
Some medications are changed and broken down by the liver. Quercetin might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)
Some medications are changed and broken down by the liver. Quercetin might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2D6 (CYP2D6) substrates)
Some medications are changed and broken down by the liver. Quercetin might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Some medications are changed and broken down by the liver. Quercetin might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications for diabetes (Antidiabetes drugs)
Quercetin might lower blood sugar levels. Taking quercetin along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.
Medications for high blood pressure (Antihypertensive drugs)
Quercetin might lower blood pressure. Taking quercetin along with medications that lower blood pressure might cause blood pressure to go too low. Monitor your blood pressure closely.
Medications moved by pumps in cells (Organic Anion Transporter 1 (OAT1) Substrates)
Some medications are moved in and out of cells by pumps. Quercetin might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.
Medications moved by pumps in cells (Organic Anion Transporter 3 (OAT3) Substrates)
Some medications are moved in and out of cells by pumps. Quercetin might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.
Medications moved by pumps in cells (Organic anion-transporting polypeptide substrates)
Some medications are moved in and out of cells by pumps. Quercetin might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.
Medications moved by pumps in cells (P-glycoprotein substrates)
Some medications are moved in and out of cells by pumps. Quercetin might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.
Midazolam (Versed)
Quercetin might increase how quickly the body breaks down midazolam. Taking quercetin with midazolam might reduce the effects of midazolam.
Quercetin might increase levels of mitoxantrone. Taking quercetin and mitoxantrone together might increase the effects and side effects of mitoxantrone.
Pravastatin (Pravachol)
Quercetin might decrease how quickly the body gets rid of pravastatin. Taking quercetin with pravastatin might increase the effects and side effects of pravastatin.
Prazosin (Minipress)
Quercetin might increase levels of prazosin. Taking quercetin and prazosin together might increase the effects and side effects of prazosin.
Quetiapine (Seroquel)
Quercetin might increase levels of quetiapine. Taking quercetin and quetiapine together might increase the effects and side effects of quetiapine.
Sulfasalazine (Azulfidine)
Quercetin might increase levels of sulfasalazine. Taking quercetin and sulfasalazine together might increase the effects and side effects of sulfasalazine.
Warfarin (Coumadin)
Quercetin might increase the effects that warfarin has on the body. Taking quercetin and warfarin together might increase the effects and side effects of warfarin, which could increase the risk of bruising and bleeding.

Are there interactions with herbs and supplements?

Herbs and supplements that might lower blood pressure
Quercetin might lower blood pressure. Taking it with other supplements that have the same effect might cause blood pressure to drop too much. Examples of supplements with this effect include andrographis, casein peptides, L-arginine, niacin, and stinging nettle.
Herbs and supplements that might lower blood sugar
Quercetin might lower blood sugar. Taking it with other supplements with similar effects might lower blood sugar too much. Examples of supplements with this effect include aloe, bitter melon, cassia cinnamon, chromium, and prickly pear cactus.

Are there interactions with foods?

There are no known interactions with foods.

How is it typically used?

Quercetin has most often been used by adults in doses of 250-1000 mg by mouth daily for up to 12 weeks. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Other names

3,3',4'5,7-Pentahydroxyflavone, Bioflavonoid, Bioflavonoid Complex, Bioflavonoid Concentrate, Bioflavonoid Extract, Bioflavonoïde, Bioflavonoïde de Citron, Bioflavonoïdes de Citron, Citrus Bioflavones, Citrus Bioflavonoid, Citrus Bioflavonoids, Citrus Bioflavonoid Extract, Citrus Flavones, Citrus Flavonoids, Complexe de Bioflavonoïde, Concentré de Bioflavonoïde, Extrait de Bioflavonoïde, Extrait de Bioflavonoïdes de Citron, Flavones de Citron, Flavonoid, Flavonoïde, Meletin, Mélétine, Quercetina, Quercétine, Sophretin, Sophrétine.


To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.


  1. Dehghani F, Vafa M, Ebrahimkhani A, Gaman MA, Sezavar Seyedi Jandaghi SH. Effects of quercetin supplementation on endothelial dysfunction biomarkers and depression in post-myocardial infarction patients: A double-blind, placebo-controlled, randomized clinical trial. Clin Nutr ESPEN 2023;56:73-80. View abstract.
  2. Nambiar A, Kellogg D 3rd, Justice J, et al. Senolytics dasatinib and quercetin in idiopathic pulmonary fibrosis: results of a phase I, single-blind, single-center, randomized, placebo-controlled pilot trial on feasibility and tolerability. EBioMedicine 2023;90:104481. View abstract.
  3. Cheema HA, Sohail A, Fatima A, et al. Quercetin for the treatment of COVID-19 patients: A systematic review and meta-analysis. Rev Med Virol 2023;33:e2427. View abstract.
  4. Di Pierro F, Khan A, Iqtadar S, et al. Quercetin as a possible complementary agent for early-stage COVID-19: Concluding results of a randomized clinical trial. Front Pharmacol. 2023 Jan 13;13:1096853. View abstract.
  5. Nakamura Y, Watanabe H, Tanaka A, Nishihira J, Murayama N. Effect of quercetin glycosides on cognitive functions and cerebral blood flow: a randomized, double-blind, and placebo-controlled study. Eur Rev Med Pharmacol Sci. 2022;26:8700-12. View abstract.
  6. Manfredi C, Spirito L, Calace FP, et al. Oral preparation of hyaluronic acid, chondroitin sulfate, curcumin, and quercetin (Ialuril(®) soft gels) for the prevention of LUTS after intravesical chemotherapy. Pathophysiology 2022;29:365-73. View abstract.
  7. Otsuka Y, Miyamoto N, Nagai A, et al. Effects of quercetin glycoside supplementation combined with low-intensity resistance training on muscle quantity and stiffness: a randomized, controlled trial. Front Nutr 2022;9:912217. View abstract.
  8. Yamada S, Shirai M, Inaba Y, Takara T. Effects of repeated oral intake of a quercetin-containing supplement on allergic reaction: a randomized, placebo-controlled, double-blind parallel-group study. Eur Rev Med Pharmacol Sci 2022;26:4331-45. View abstract.
  9. Ahmad E, Jahangir M, Ismail MA, et al. Influence of quercetin pretreatment on pharmacokinetics of warfarin in rats. Curr Drug Saf 2022. View abstract.
  10. Vaez S, Parivr K, Amidi F, Rudbari NH, Moini A, Amini N. Quercetin and polycystic ovary syndrome; inflammation, hormonal parameters and pregnancy outcome: a randomized clinical trial. Am J Reprod Immunol 2022. View abstract.
  11. Popiolek-Kalisz J, Fornal E. The effects of quercetin supplementation on blood pressure - meta-analysis. Curr Probl Cardiol 2022;47:101350. View abstract.
  12. Song YK, Yoon JH, Woo JK, et al. Quercetin is a flavonoid breast cancer resistance protein inhibitor with an impact on the oral pharmacokinetics of sulfasalazine in rats. Pharmaceutics 2020;12:397. View abstract.
  13. Cheraghi E, Sajadi SMS, Soleimani Mehranjani M. The effect of quercetin on the quality of sperm parameters in frozen-thawed semen of patients with asthenospermia. Andrologia 2021;53:e14167. View abstract.
  14. Shohan M, Nashibi R, Mahmoudian-Sani MR, et al. The therapeutic efficacy of quercetin in combination with antiviral drugs in hospitalized COVID-19 patients: a randomized controlled trial. Eur J Pharmacol 2022;914:174615. View abstract.
  15. Di Pierro F, Iqtadar S, Khan A, et al. Potential clinical benefits of quercetin in the early stage of COVID-19: results of a second, pilot, randomized, controlled and open-label clinical trial. Int J Gen Med 2021;14:2807-16. View abstract.
  16. Di Pierro F, Derosa G, Maffioli P, et al. Possible therapeutic effects of adjuvant quercetin supplementation against early-stage COVID-19 infection: a prospective, randomized, controlled, and open-label study. Int J Gen Med 2021;14:2359-66. View abstract.
  17. Heinz SA, Henson DA, Austin MD, Jin F, Nieman DC. Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial. Pharmacol Res. 2010;62:237-42. View abstract.
  18. Knab AM, Shanely RA, Jin F, Austin MD, Sha W, Nieman DC. Quercetin with vitamin C and niacin does not affect body mass or composition. Appl Physiol Nutr Metab. 2011;36:331-8. View abstract.
  19. Hamdy AA, Ibrahem MA. Management of aphthous ulceration with topical quercetin: a randomized clinical trial. J Contemp Dent Pract. 2010;11:E009-16. View abstract.
  20. Marseglia G, Licari A, Leonardi S, et al. A polycentric, randomized, parallel-group, study on Lertal®, a multicomponent nutraceutical, as preventive treatment in children with allergic rhinoconjunctivitis: phase II. Ital J Pediatr. 2019;45:84. View abstract.
  21. Ni Y, Duan Z, Zhou D, et al. Identification of Structural Features for the Inhibition of OAT3-Mediated Uptake of Enalaprilat by Selected Drugs and Flavonoids. Front Pharmacol. 2020;11:802. View abstract.
  22. Li C, Wang X, Bi Y, et al. Potent Inhibitors of Organic Anion Transporters 1 and 3 From Natural Compounds and Their Protective Effect on Aristolochic Acid Nephropathy. Toxicol Sci. 2020;175:279-291. View abstract.
  23. Huang H, Liao D, Dong Y, Pu R. Effect of quercetin supplementation on plasma lipid profiles, blood pressure, and glucose levels: a systematic review and meta-analysis. Nutr Rev. 2020;78:615-626. View abstract.
  24. Bhutani P, Rajanna PK, Paul AT. Impact of quercetin on pharmacokinetics of quetiapine: insights from in-vivo studies in wistar rats. Xenobiotica. 2020:1-7. View abstract.
  25. Ou Q, Zheng Z, Zhao Y, Lin W. Impact of quercetin on systemic levels of inflammation: a meta-analysis of randomised controlled human trials. Int J Food Sci Nutr. 2020;71:152-163. View abstract.
  26. Bazzucchi I, Patrizio F, Ceci R, et al. Quercetin Supplementation Improves Neuromuscular Function Recovery from Muscle Damage. Nutrients. 2020;12:E2850. View abstract.
  27. Sajadi Hezaveh Z, Azarkeivan A, Janani L, Hosseini S, Shidfar F. The effect of quercetin on iron overload and inflammation in ß-thalassemia major patients: a double-blind randomized clinical trial. Complement Ther Med 2019;46:24-8. View abstract.
  28. Cesarone MR, Belcaro G, Hu S, et al. Supplementary prevention and management of asthma with quercetin phytosome: a pilot registry. Minerva Med 2019;110:524-9. View abstract.
  29. Vicente-Vicente L, González-Calle D, Casanova AG, et al. Quercetin, a promising clinical candidate for the prevention of contrast-induced nephropathy. Int J Mol Sci 2019;20:4961. View abstract.
  30. Zhao Q, Wei J, Zhang H. Effects of quercetin on the pharmacokinetics of losartan and its metabolite EXP3174 in rats. Xenobiotica 2019;49:563-8. View abstract.
  31. Ostadmohammadi V, Milajerdi A, Ayati E, Kolahdooz F, Asemi Z. Effects of quercetin supplementation on glycemic control among patients with metabolic syndrome and related disorders: a systematic review and meta-analysis of randomized controlled trials. Phytother Res 2019;33:1330-40. View abstract.
  32. Riva A, Ronchi M, Petrangolini G, Bosisio S, Allegrini P. Improved oral absorption of quercetin from Quercetin Phytosome®, a new delivery system based on food grade lecithin. Eur J Drug Metab Pharmacokinet 2019;44:169-77. View abstract.
  33. Khorshidi M, Moini A, Alipoor E, et al. The effects of quercetin supplementation on metabolic and hormonal parameters as well as plasma concentration and gene expression of resistin in overweight or obese women with polycystic ovary syndrome. Phytother Res. 2018;32:2282-2289. View abstract.
  34. Bazzucchi I, Patrizio F, Ceci R, et al. The effects of quercetin supplementation on eccentric exercise-induced muscle damage. Nutrients. 2019;11. pii: E205. View abstract.
  35. Bedada SK, Neerati P. Evaluation of the effect of quercetin treatment on CYP2C9 enzyme activity of diclofenac in healthy human volunteers. Phytother Res. 2018 Feb;32:305-311. doi: 10.1002/ptr.5978. View abstract.
  36. Suardi N, Gandaglia G, Nini A, et al. Effects of Difaprost® on voiding dysfunction, histology and inflammation markers in patients with benign prostatic hyperplasia who are candidates for surgical treatment. Minerva Urol Nefrol. 2014;66:119-25. View abstract.
  37. Sahebkar A. Effects of quercetin supplementation on lipid profile: A systematic review and meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr. 2017;57:666-676. View abstract.
  38. Rezvan N, Moini A, Janani L, et al. Effects of quercetin on adiponectin-mediated insulin sensitivity in polycystic ovary syndrome: A randomized placebo-controlled double-blind clinical trial. Horm Metab Res. 2017;49:115-121. View abstract.
  39. Torella M, Del Deo F, Grimaldi A, et al. Efficacy of an orally administered combination of hyaluronic acid, chondroitin sulfate, curcumin and quercetin for the prevention of recurrent urinary tract infections in postmenopausal women. Eur J Obstet Gynecol Reprod Biol. 2016;207:125-128. View abstract.
  40. Larson A, Witman MA, Guo Y, et al. Acute, quercetin-induced reductions in blood pressure in hypertensive individuals are not secondary to lower plasma angiotensin-converting enzyme activity or endothelin-1: nitric oxide. Nutr Res. 2012;32:557-64. View abstract.
  41. Ahrens MJ, Thompson DL. Effect of emulin on blood glucose in type 2 diabetics. J Med Food. 2013;16:211-5. View abstract.
  42. Woo HD, Kim J. Dietary flavonoid intake and smoking-related cancer risk: a meta-analysis. PLoS One. 2013;8:e75604. View abstract.
  43. Palleschi G, Carbone A, Ripoli A, et al. A prospective study to evaluate the efficacy of Cistiquer in improving lower urinary tract symptoms in females with urethral syndrome. Minerva Urol Nefrol. 2014;66:225-32. View abstract.
  44. Kooshyar MM, Mozafari PM, Amirchaghmaghi M, et al. A randomized placebo-controlled double blind clinical trial of quercetin in the prevention and treatment of chemotherapy-induced oral mucositis. J Clin Diagn Res. 2017;11:ZC46-ZC50. View abstract.
  45. Serban MC, Sahebkar A, Zanchetti A, et al; Lipid and Blood Pressure Meta-analysis Collaboration (LBPMC) Group. Effects of quercetin on blood pressure: A systematic review and meta-analysis of randomized controlled trials. J Am Heart Assoc. 2016;5. pii: e002713. View abstract.
  46. Javadi F, Ahmadzadeh A, Eghtesadi S, et al. The effect of quercetin on inflammatory factors and clinical symptoms in women with rheumatoid arthritis: A double-blind, randomized controlled trial. J Am Coll Nutr. 2017;36:9-15. View abstract.
  47. Taliou A, Zintzaras E, Lykouras L, Francis K. An open-label pilot study of a formulation containing the anti-inflammatory flavonoid luteolin and its effects on behavior in children with autism spectrum disorders. Clin Ther. 2013;35:592-602. View abstract.
  48. Nishijima T, Takida Y, Saito Y, Ikeda T, Iwai K. Simultaneous ingestion of high-methoxy pectin from apple can enhance absorption of quercetin in human subjects. Br J Nutr. 2015 May 28;113:1531-8. View abstract.
  49. Wu LX, Guo CX, Chen WQ, et al. Inhibition of the organic anion-transporting polypeptide 1B1 by quercetin: an in vitro and in vivo assessment. Br J Clin Pharmacol 2012;73:750-7. View abstract.
  50. Nguyen MA, Staubach P, Wolffram S, Langguth P. Effect of single-dose and short-term administration of quercetin on the pharmacokinetics of talinolol in humans - Implications for the evaluation of transporter-mediated flavonoid-drug interactions. Eur J Pharm Sci 2014;61:54-60. View abstract.
  51. Wang SY, Duan KM, Li Y, et al. Effect of quercetin on P-glycoprotein transport ability in Chinese healthy subjects. Eur J Clin Nutr 2013;67:390-4. View abstract.
  52. Sharp MA, Hendrickson NR, Staab JS, et al. Effects of short-term quercetin supplementation on soldier performance. J Strength Cond Res 2012;26 Suppl 2:S53-60. View abstract.
  53. Pelletier DM, Lacerte G, Goulet ED. Effects of quercetin supplementation on endurance performance and maximal oxygen consumption: a meta-analysis. Int J Sport Nutr Exerc Metab 2013;23:73-82. View abstract.
  54. Guo Y, Mah E, Davis CG, et al. Dietary fat increases quercetin bioavailability in overweight adults. Mol Nutr Food Res 2013;57:896-905. View abstract.
  55. Duan KM, Wang SY, Ouyang W, Mao YM, Yang LJ. Effect of quercetin on CYP3A activity in Chinese healthy participants. J Clin Pharmacol 2012;52:940-6. View abstract.
  56. Hollman, PC, Bijsman, MN, van Gameren, Y, Cnossen, EP, de Vries, JH, and Katan, MB. The sugar moiety is a major determinant of the absorption of dietary flavonoid glycosides in man. Free Radic.Res. 1999;31:569-573.
  57. Hayek, T., Fuhrman, B., Vaya, J., Rosenblat, M., Belinky, P., Coleman, R., Elis, A., and Aviram, M. Reduced progression of atherosclerosis in apolipoprotein E-deficient mice following consumption of red wine, or its polyphenols quercetin or catechin, is associated with reduced susceptibility of LDL to oxidation and aggregation. Arterioscler.Thromb.Vasc.Biol 1997;17:2744-2752. View abstract.
  58. Loke, W. M., Hodgson, J. M., Proudfoot, J. M., McKinley, A. J., Puddey, I. B., and Croft, K. D. Pure dietary flavonoids quercetin and (-)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men. Am J Clin Nutr 2008;88:1018-1025. View abstract.
  59. Egert, S., Wolffram, S., Bosy-Westphal, A., Boesch-Saadatmandi, C., Wagner, A. E., Frank, J., Rimbach, G., and Mueller, M. J. Daily quercetin supplementation dose-dependently increases plasma quercetin concentrations in healthy humans. J Nutr 2008;138:1615-1621. View abstract.
  60. Dhar, N. B. and Shoskes, D. A. New therapies in chronic prostatitis. Curr.Urol.Rep. 2007;8:313-318. View abstract.
  61. Murakami, A., Ashida, H., and Terao, J. Multitargeted cancer prevention by quercetin. Cancer Lett. 10-8-2008;269:315-325. View abstract.
  62. Boots, A. W., Haenen, G. R., and Bast, A. Health effects of quercetin: from antioxidant to nutraceutical. Eur.J Pharmacol 5-13-2008;585(2-3):325-337. View abstract.
  63. McAnulty, S. R., McAnulty, L. S., Nieman, D. C., Quindry, J. C., Hosick, P. A., Hudson, M. H., Still, L., Henson, D. A., Milne, G. L., Morrow, J. D., Dumke, C. L., Utter, A. C., Triplett, N. T., and Dibarnardi, A. Chronic quercetin ingestion and exercise-induced oxidative damage and inflammation. Appl.Physiol Nutr Metab 2008;33:254-262. View abstract.
  64. Negre-Salvayre, A. and Salvayre, R. Quercetin prevents the cytotoxicity of oxidized LDL on lymphoid cell lines. Free Radic.Biol.Med. 1992;12:101-106. View abstract.
  65. Alexandrakis, M., Letourneau, R., Kempuraj, D., Kandere-Grzybowska, K., Huang, M., Christodoulou, S., Boucher, W., Seretakis, D., and Theoharides, T. C. Flavones inhibit proliferation and increase mediator content in human leukemic mast cells (HMC-1). Eur.J Haematol. 2003;71:448-454. View abstract.
  66. Gugler, R., Leschik, M., and Dengler, H. J. Disposition of quercetin in man after single oral and intravenous doses. Eur.J.Clin.Pharmacol. 12-19-1975;9(2-3):229-234. View abstract.
  67. Kang, L. P., Qi, L. H., Zhang, J. P., Shi, N., Zhang, M., Wu, T. M., and Chen, J. Effect of genistein and quercetin on proliferation, collagen synthesis, and type I procollagen mRNA levels of rat hepatic stellate cells. Acta Pharmacol.Sin. 2001;22:793-796. View abstract.
  68. Walle, T., Walle, U. K., and Halushka, P. V. Carbon dioxide is the major metabolite of quercetin in humans. J.Nutr. 2001;131:2648-2652. View abstract.
  69. Erlund, I., Alfthan, G., Maenpaa, J., and Aro, A. Tea and coronary heart disease: the flavonoid quercetin is more bioavailable from rutin in women than in men. Arch.Intern.Med. 8-13-2001;161:1919-1920. View abstract.
  70. Chopra, M., Fitzsimons, P. E., Strain, J. J., Thurnham, D. I., and Howard, A. N. Nonalcoholic red wine extract and quercetin inhibit LDL oxidation without affecting plasma antioxidant vitamin and carotenoid concentrations. Clin.Chem. 2000;46(8 Pt 1):1162-1170. View abstract.
  71. Lamson, D. W. and Brignall, M. S. Antioxidants and cancer, part 3: quercetin. Altern.Med.Rev. 2000;5:196-208. View abstract.
  72. Crespy, V., Morand, C., Manach, C., Besson, C., Demigne, C., and Remesy, C. Part of quercetin absorbed in the small intestine is conjugated and further secreted in the intestinal lumen. Am J Physiol 1999;277(1 Pt 1):G120-G126. View abstract.
  73. Hollman, P. C., van Trijp, J. M., Mengelers, M. J., de Vries, J. H., and Katan, M. B. Bioavailability of the dietary antioxidant flavonol quercetin in man. Cancer Lett. 3-19-1997;114(1-2):139-140. View abstract.
  74. Hollman, P. C., de Vries, J. H., van Leeuwen, S. D., Mengelers, M. J., and Katan, M. B. Absorption of dietary quercetin glycosides and quercetin in healthy ileostomy volunteers. Am.J.Clin.Nutr. 1995;62:1276-1282. View abstract.
  75. Wiczkowski, W., Romaszko, J., Bucinski, A., Szawara-Nowak, D., Honke, J., Zielinski, H., and Piskula, M. K. Quercetin from shallots (Allium cepa L. var. aggregatum) is more bioavailable than its glucosides. J Nutr 2008;138:885-888. View abstract.
  76. Terao, J., Kawai, Y., and Murota, K. Vegetable flavonoids and cardiovascular disease. Asia Pac.J Clin Nutr 2008;17 Suppl 1:291-293. View abstract.
  77. Beatty, E. R., O'Reilly, J. D., England, T. G., McAnlis, G. T., Young, I. S., Geissler, C. A., Sanders, T. A., and Wiseman, H. Effect of dietary quercetin on oxidative DNA damage in healthy human subjects. Br J Nutr 2000;84:919-925. View abstract.
  78. O'Reilly, J. D., Sanders, T. A., and Wiseman, H. Flavonoids protect against oxidative damage to LDL in vitro: use in selection of a flavonoid rich diet and relevance to LDL oxidation resistance ex vivo? Free Radic.Res 2000;33:419-426. View abstract.
  79. Kaul, T. N., Middleton E Jr, and Ogra, P. L. Antiviral effect of flavonoids on human viruses. J.Med.Virol. 1985;15:71-79. View abstract.
  80. Rayalam, S., Della-Fera, M. A., and Baile, C. A. Phytochemicals and regulation of the adipocyte life cycle. J Nutr Biochem. 2008;19:717-726. View abstract.
  81. de Vries, J. H., Hollman, P. C., Meyboom, S., Buysman, M. N., Zock, P. L., van Staveren, W. A., and Katan, M. B. Plasma concentrations and urinary excretion of the antioxidant flavonols quercetin and kaempferol as biomarkers for dietary intake. Am.J Clin Nutr. 1998;68:60-65. View abstract.
  82. Havsteen, B. Flavonoids, a class of natural products of high pharmacological potency. Biochem.Pharmacol 4-1-1983;32:1141-1148. View abstract.
  83. Nieman, D. C. Immunonutrition support for athletes. Nutr.Rev. 2008;66:310-320. View abstract.
  84. Young, J. F., Nielsen, S. E., Haraldsdottir, J., Daneshvar, B., Lauridsen, S. T., Knuthsen, P., Crozier, A., Sandstrom, B., and Dragsted, L. O. Effect of fruit juice intake on urinary quercetin excretion and biomarkers of antioxidative status. Am J Clin Nutr 1999;69:87-94. View abstract.
  85. Mayer, B., Schumacher, M., Brandstatter, H., Wagner, F. S., and Hermetter, A. High-throughput fluorescence screening of antioxidative capacity in human serum. Anal.Biochem 10-15-2001;297:144-153. View abstract.
  86. Di Bari L, Ripoli S, Pradhan S, Salvadori P. Interactions between quercetin and warfarin for albumin binding: A new eye on food/drug interference. Chirality 2010;22:593-6. View abstract.
  87. Vaclavikova R, Horsky S, Simek P, Gut I. Paclitaxel metabolism in rat and human liver microsomes is inhibited by phenolic antioxidants. Naunyn Schmiedebergs Arch Pharmacol 2003;368:200-9. View abstract.
  88. Choi JS, Jo BW, Kim YC. Enhanced paclitaxel bioavailability after oral administration of paclitaxel or prodrug to rats pretreated with quercetin. Eur J Pharm Biopharm 2004;57:313-8. View abstract.
  89. Choi JS, Choi BC, Choi KE. Effect of quercetin on the pharmacokinetics of oral cyclosporine. Am J Health Syst Pharm 2004;61:2406-9. View abstract.
  90. DiCenzo R, Frerichs V, Larppanichpoonphol P, et al. Effect of quercetin on the plasma and intracellular concentrations of saquinavir in healthy adults. Pharmacotherapy 2006;26:1255-61. View abstract.
  91. Kim KA, Park PW, Kim HK, et al. Effect of quercetin on the pharmacokinetics of rosiglitazone, a CYP2C8 substrate, in healthy subjects. J Clin Pharmacol 2005;45:941-6. View abstract.
  92. Nieman DC, Henson DA, Davis JM, et al. Quercetin ingestion does not alter cytokine changes in athletes competing in the Western States Endurance Run. J Interferon Cytokine Res 2007;27:1003-11. View abstract.
  93. Nieman DC, Henson DA, Gross SJ, et al. Quercetin reduces illness but not immune perturbations after intensive exercise. Med Sci Sports Exerc 2007;39:1561-9. View abstract.
  94. Nieman DC, Henson DA, Davis JM, et al. Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA. J Appl Physiol 2007;103:1728-35. View abstract.
  95. Gates MA, Tworoger SS, Hecht JL, et al. A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer. Int J Cancer 2007;121:2225-32. View abstract.
  96. Bobe G, Weinstein SJ, Albanes D, et al. Flavonoid intake and risk of pancreatic cancer in male smokers (Finland). Cancer Epidemiol Biomarkers Prev 2008;17:553-62. View abstract.
  97. Nöthlings U, Murphy SP, Wilkens LR, et al. Flavonols and pancreatic cancer risk: the multiethnic cohort study. Am J Epidemiol 2007;166:924-31. View abstract.
  98. Perez-Vizcaino F, Duarte J, Andriantsitohaina R. Endothelial function and cardiovascular disease: effects of quercetin and wine polyphenols. Free Radic Res 2006;40:1054-65. View abstract.
  99. Edwards RL, Lyon T, Litwin SE, et al. Quercetin reduces blood pressure in hypertensive subjects. J Nutr 2007;137:2405-11. View abstract.
  100. Nemeth K, Piskula MK. Food content, processing, absorption and metabolism of onion flavonoids. Crit Rev Food Sci Nutr 2007;47:397-409. View abstract.
  101. Murota K, Terao J. Antioxidative flavonoid quercetin: implication of its intestinal absorption and metabolism. Arch Biochem Biophys 2003;417:12-7. View abstract.
  102. Erlund I, Freese R, Marniemi J, et al. Bioavailability of quercetin from berries and the diet. Nutr Cancer 2006;54:13-7. View abstract.
  103. Shoskes D, Lapierre C, Cruz-Corerra M, et al. Beneficial effects of the bioflavonoids curcumin and quercetin on early function in cadaveric renal transplantation: a randomized placebo controlled trial. Transplantation 2005;80:1556-9. View abstract.
  104. Hubbard GP, Wolffram S, Lovegrove JA, Gibbins JM. Ingestion of quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in humans. J Thromb Haemost 2004;2:2138-45. View abstract.
  105. Harwood M, Danielewska-Nikiel B, Borzelleca JF, et al. A critical review of the data related to the safety of quercetin and lack of evidence of in vivo toxicity, including lack of genotoxic / carcinogenic properties. Food Chem Toxicol 2007;45:2179-205. View abstract.
  106. Obach RS. Inhibition of human cytochrome P450 enzymes by constituents of St. John's wort, an herbal preparation used in the treatment of depression. J Pharmacol Exp Ther 2000;294:88-95. View abstract.
  107. de Pascual-Teresa S, Johnston KL, DuPont MS, et al. Quercetin metabolites downregulate cyclooxygenase-2 transcription in human lymphocytes ex vivo but not in vivo. J Nutr 2004;134:552-7. View abstract.
  108. Ferry DR, Smith A, Malkhandi J, et al. Phase I clinical trial of the flavonoid quercetin: Pharmacokinetics and evidence for in vivo tyrosine kinase inhibition. Clin Cancer Res 1996;2:659-67.. View abstract.
  109. Starvic B. Quercetin in our diet: from potent mutagen to probable anticarcinogen. Clin Biochem 1994;27:245-8.
  110. Koga T, Meydani M. Effect of plasma metabolites of (+)-catechin and quercetin on monocyte adhesion to human aortic endothelial cells. Am J Clin Nutr 2001;73:941-8.. View abstract.
  111. Walle T, Otake Y, Walle UK, Wilson FA. Quercetin glucosides are completely hydrolyzed in ileostomy patients before absorption. J Nutr 2000;130:2658-61.. View abstract.
  112. Erlund I, Kosonen T, Alfthan G, et al. Pharmacokinetics of quercetin from quercetin aglycone and rutin in healthy volunteers. Eur J Clin Pharmacol 2000;56:545-53.. View abstract.
  113. Otsuka H, Inaba M, Fujikura T, Kunitomo M. Histochemical and functional characteristics of metachromatic cells in the nasal epithelium in allergic rhinitis: studies of nasal scrapings and their dispersed cells. J Allergy Clin Immunol 1995;96:528-36.. View abstract.
  114. Sesink AL, O'Leary KA, Hollman PC. Quercetin glucuronides but not glucosides are present in human plasma after consumption of quercetin-3-glucoside or quercetin-4'-glucoside. J Nutr 2001;131:1938-41.. View abstract.
  115. Goldberg DM, Yan J, Soleas GJ. Absorption of three wine-related polyphenols in three different matrices by healthy subjects. Clin Biochem 2003;36:79-87.. View abstract.
  116. de Vries JH, Hollman PC, van Amersfoort I, et al. Red wine is a poor source of bioavailable flavonols in men. J Nutr 2001;131:745-8. View abstract.
  117. Hertog MG, Feskens EJ, Hollman PC, et al. Dietary antioxidant flavonoids and risk of coronary heart disease: the Zutphen Elderly Study. Lancet 1993;342:1007-1011. View abstract.
  118. Janssen K, Mensink RP, Cox FJ, et al. Effects of the flavonoids quercetin and apigenin on hemostasis in healthy volunteers: results from an in vitro and a dietary supplement study. Am J Clin Nutr 1998;67:255-62. View abstract.
  119. Conquer JA, Maiani G, Azzini E, et al. Supplementation with quercetin markedly increases plasma quercetin concentration without effect on selected risk factors for heart disease in healthy subjects. J Nutr 1998;128:593-7. View abstract.
  120. Kuo SM, Leavitt PS, Lin CP. Dietary flavonoids interact with trace metals and affect metallothionein level in human intestinal cells. Biol Trace Elem Res 1998;62:135-53. View abstract.
  121. Rachkauskas GS. The efficacy of enterosorption and a combination of antioxidants in schizophrenics. Lik Sprava 1998;4:122-4. View abstract.
  122. Lean ME, Noroozi M, Kelly I. Dietary flavonols protect diabetic human lymphocytes against oxidative damage to DNA. Diabetes 1999;48:176-81. View abstract.
  123. Huang Z, Fasco MJ, Kaminsky LS. Inhibition of estrone sulfatase in human liver microsomes by quercetin and other flavonoids. J Steroid Biochem Mol Biol 1997;63:9-15. View abstract.
  124. McAnlis GT, McEneny J, Pearce J, Young IS. Absorption and antioxidant effects of quercetin from onions, in man. Eur J Clin Nutr 1999;53:92-6. View abstract.
  125. Wiseman H. The bioavailability of non-nutrient plant factors: dietary flavonoids and phyto-oestrogens. Proc Nutr Soc 1999;58:139-46. View abstract.
  126. El Attar TM, Virji AS. Modulating effect of resveratrol and quercetin on oral cancer cell growth and proliferation. Anticancer Drugs 1999;10:187-93. View abstract.
  127. Miodini P, Fioravanti L, Di Fronzo G, Cappelletti V. The two phyto-oestrogens genistein and quercetin exert different effects on oestrogen receptor function. Br J Cancer 1999;80:1150-5. View abstract.
  128. Anon. Quercetin. Alt Med Rev 1998;3:140-3.
  129. Shoskes DA, Zeitlin SI, Shahed A, Rajfer J. Quercetin in men with category III chronic prostatitis: A preliminary prospective, double-blind, placebo-controlled trial. Urol 1999;54:960-3. View abstract.
Last reviewed - 02/07/2024