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Austrian chemist Heinrich Hlasiwetz (1825-1875) is remembered for his chemical analysis of quercitrin.
Quercitrin is a constituent of the dye quercitron. It can be found in Tartary buckwheat (Fagopyrum tataricum) and in oaks species like the North American white oak (Quercus alba) and English oak (Quercus robur). It is also found in Nymphaea odorata or Taxillus kaempferi.
Quercetin is a plant pigment (flavonoid). It is found in many plants and foods, such as red wine, onions, green tea, apples, berries, Ginkgo biloba, St. John's wort, American elder, and others. Buckwheat tea has a large amount of quercetin. People use quercetin as a medicine.
Quercetin is used for treating conditions of the heart and blood vessels including “hardening of the arteries” (atherosclerosis), high cholesterol, heart disease, and circulation problems. It is also used for diabetes, cataracts, hay fever, peptic ulcer, schizophrenia, inflammation, asthma, gout, viral infections, chronic fatigue syndrome (CFS), preventing cancer, and for treating chronic infections of the prostate. Quercetin is also used to increase endurance and improve athletic performance.
How does it work?
Quercetin has antioxidant and anti-inflammatory effects which might help reduce prostate inflammation.
Possibly Effective for
Prostate pain and swelling (inflammation). Taking quercetin by mouth seems to reduce pain and improve quality of life, but doesn't seem to help urination problems in men with ongoing prostate problems that aren't due to infection.
Insufficient Evidence for
- Heart disease. Some research suggests that eating foods rich in quercetin, such as tea, onions and apples, can reduce the risk of heart disease-related death in elderly men. However, other early research suggests that taking a daily quercetin supplement does not improve heart disease risk factors.
- High cholesterol. Short-term use of quercetin supplements does not seem to lower “bad cholesterol” (low-density lipoprotein (LDL) cholesterol), lower total cholesterol, or raise “good cholesterol” (high-density lipoprotein (HDL) cholesterol).
- High blood pressure. Some research suggest that 365 mg of quercetin aglycone twice daily produces a small (5-7 mmHg) decrease in blood pressure in people with untreated, mild high blood pressure. It’s not known yet how important this is.
- Exercise-induced respiratory infections. Developing research shows that taking 500 mg of quercetin twice daily for 3 weeks before, and continuing during 3 days of extended, intense cycling reduces the number of upper respiratory infections in the 14 days following the heavy exercise.
- Kidney transplantation. Some research suggests that a combination of 20 mg of quercetin and 480 mg of curcumin taken once or twice daily, starting within 24 hours of kidney transplantation and continuing for one month, in combination with anti-rejection drugs, improves early function of the transplanted kidney.
- Lung cancer. Some research suggests that consuming high amounts of quercetin in the diet might reduce the chance of developing lung cancer, especially in men who smoke.
- Ovarian cancer. One study found no link between quercetin intake from the diet and the chance of ovarian cancer.
- Pancreatic cancer. Some research suggests that eating high amounts of quercetin in the diet might reduce the chance of developing pancreatic cancer, especially in men who smoke.
- “Hardening of the arteries” (atherosclerosis).
- Hay fever (allergic rhinitis).
- Stomach and intestinal ulcers.
- Pain and swelling (inflammation).
- Viral infections.
- Chronic fatigue syndrome (CFS).
- Other conditions.
More evidence is needed to rate quercetin for these uses.
Quercetin is POSSIBLY SAFE for most people when taken by mouth short-term. Quercetin has been safely used in amounts up to 500 mg twice daily for 12 weeks. It is not known if longer-term use or larger amounts are safe.
Quercetin can cause headache and tingling of the arms and legs. Very high doses might cause kidney damage.
When given intravenously (by IV) in appropriate amounts (less than 722 mg), quercetin is POSSIBLY SAFE. But larger amounts given by IV are POSSIBLY UNSAFE. There have been reports of kidney damage at higher doses. Special Precautions & Warnings: Pregnancy and breast-feeding: Not enough is known about the use of quercetin during pregnancy and breast-feeding. Stay on the safe side and avoid use.
The following dose has been studied in scientific research:
- For prostate pain and swelling (prostatitis): 500 mg twice daily.
- Tartary Buckwheat (Fagopyrum tataricum Gaertn.) as a Source of Dietary Rutin and Quercitrin. Nina Fabjan, Janko Rode, Iztok Jože Košir, Zhuanhua Wang, Zheng Zhang and Ivan Kreft, J. Agric. Food Chem., 2003, 51 (22), pp. 6452–6455, doi:10.1021/jf034543e
- Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. Pirjo Mämmelä, Heikki Savolainenb, Lasse Lindroosa, Juhani Kangasd and Terttu Vartiainen, Journal of Chromatography A, Volume 891, Issue 1, 1 September 2000, Pages 75-83, doi:10.1016/S0021-9673(00)00624-5
- The constituents of Taxillus kaempferi and the host, Pinus thunbergii. I. Catechins and flavones of Taxillus kaempferi. Konishi T, Nishio T, Kiyosawa S, Fujiwara Y and Konoshima T, Yakugaku Zasshi., February 1996, volume 116, issue 2, pages 148-157 (article in Japanese)
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