Definition:Quercetin belongs to a group of plant pigments called flavonoids that are largely responsible for the colors of many fruits, flowers, and vegetables. Flavonoids, such as quercetin, provide many health-promoting benefits. They act as antihistamines (which are useful in reducing allergy symptoms) and help reduce inflammation associated with various forms of arthritis. Quercetin also works as an antioxidant by scavenging damaging particles in the body known as free radicals. These particles occur naturally in the body but can damage cell membranes, interact with genetic material, and possibly contribute to the aging process as well as the development of a number of conditions including heart disease and cancer. Antioxidants such as quercetin can neutralize free radicals and may reduce or even help prevent some of the damage they cause.
Quercetin is a phytochemical that is part of the coloring found in the skins of apples and red onions. It has been isolated and is sold as a dietary supplement.
Apples are an excellent source of quercetin…………image of quercetin.png
Quercetin is a flavonoid and, to be more specific, a flavonol. It is the aglycone form of a number of other flavonoid glycosides, such as rutin and quercitrin, found in citrus fruit, buckwheat and onions. Quercetin forms the glycosides quercitrin and rutin together with rhamnose and rutinose, respectively.
Quercetin is a naturally-occurring polar auxin transport inhibitor.
Foods rich in quercetin include capers (1800mg/kg), lovage (1700mg/kg), apples (440mg/kg), tea (Camellia sinensis), onions, especially in red onions (higher concentrations of quercetin occur in the outermost rings), red grapes, citrus fruits, broccoli and other leafy green vegetables, cherries, and a number of berries including raspberry, bog whortleberry (158 mg/kg, fresh weight), lingonberry (cultivated 74mg/kg, wild 146 mg/kg), cranberry (cultivated 83 mg/kg, wild 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), crowberry (cultivated 53mg/kg, wild 56 mg/kg), and the fruit of the prickly pear cactus. A recent study found that organically grown tomatoes had 79% more quercetin than “conventionally grown”.
A study by the University of Queensland, Australia, has also indicated the presence of quercetin in varieties of honey, including honey derived from eucalyptus and tea tree flower
Where To Find Quercetin:
To get more quercetin, you can increase your intake of apples and red onions, which will improve your diet. If you need more therapeutic impact, quercetin is available in health food stores and online.
Quercetin is found to be the most active of the flavonoids in studies, and many medicinal plants owe much of their activity to their high quercetin content. Quercetin has demonstrated significant anti-inflammatory activity because of direct inhibition of several initial processes of inflammation. For example, it inhibits both the manufacture and release of histamine and other allergic/inflammatory mediators. In addition, it exerts potent antioxidant activity and vitamin C-sparing action.
Quercetin’s anti-histamine action may help to relieve allergic symptoms and asthma symptoms. The anti-inflammatory properties may help to reduce pain from disorders such as arthritis. Men who are concerned about prostate problems would also benefit from quercetin. Quercetin may also help reduce symptoms like fatigue, depression and anxiety.
Quercetin also shows anti-tumour properties. A study in the British Journal of Cancer showed that, when treated with a combination of quercetin and ultrasound at 20 kHz for 1 minute duration, skin and prostate cancers show a 90% mortality within 48 hours with no visible mortality of normal cells. Note that ultrasound also promotes topical absorption by up to 1,000 times making the use of topical quercetin and ultrasound wands an interesting proposition.
Recent studies have supported that quercetin can help men with chronic prostatitis, and both men and women with interstitial cystitis, possibly because of its action as a mast cell inhibitor.
Quercetin is a powerful antioxidant. It is also a natural anti-histamine, and anti-inflammatory. Research shows that quercetin may help to prevent cancer, especially prostate cancer.
Quercetin may have positive effects in combating or helping to prevent cancer, prostatitis, heart disease, cataracts, allergies/inflammations, and respiratory diseases such as bronchitis and asthma. It also has been claimed to have antidepressant properties, however any claim of quercetin action against neurological diseases should be treated with skepticism due to the fact that quercitin is a neurotoxin in vitIt also may be found in dietary supplements.
An 8-year study found that three flavonols — kaempferol, quercetin, and myricetin — were associated with a reduced risk of pancreatic cancer of 23 percent.
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Quercetin is contraindicated with antibiotics; it may interact with fluoroquinolones (a type of medicinal antibiotic), as quercetin competitively binds to bacterial DNA gyrase. Whether this inhibits or enhances the effect of fluoroquinolones is not entirely clear.
Quercetin is also a potent inhibitor of CYP3A4, an enzyme that breaks down most drugs in the body. As such, quercetin would be expected to increase serum levels, and therefore effects, of drugs metabolized by this enzyme