Article: Quercetin

Systematic name Quercetin
Chemical formula C15H10O7
Molecular mass 302.236 g/mol
Density 1.799 g/cm3
Melting point 316 °C
Boiling point xx.x °C
CAS number 117-39-5
SMILES xxxxx
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Quercetin is a flavonoid that forms the "backbone" for many other flavonoids, including the citrus flavonoids rutin, hesperidin, naringin and tangeritin. 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.

Together with rhamnose, it forms a glycoside quercitrin.

Quercetin also shows remarkable anti-tumour properties. A recent study in the British Journal of Cancer shows that in combination with 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.

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.

Foods rich in quercetin include apples, black & green tea, onions (higher concentrations of quercetin occur in the outermost rings[1]), raspberries, red wine, red grapes, citrus fruits, broccoli & other leafy green vegetables, and cherries. A study[2] 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 flowers.[3]

See also

  • Phytonutrients


  • Quercetin (University of Maryland Medical Center)