What is Quercetin?


Quercetin is a phytochemical that is part of the coloring found in the skins of apples and red onions. It is the most abundant of the flavonoids, and is also a building block for other flavonoids. It is a powerful antioxidant, as well as being a natural antihistamine and anti-inflammatory. About 70 percent of the total flavonoid intake from food comes from quercetin.

Quercetin is the most well researched of all the bioflavonoids. It shows good synergism with other bioflavonoids. It increases the absorption of green tea Catechins and synergistically increases the potency, thus allowing benefits of each at a reduced level of intake.

What Does Quercetin Do?
Quercetin has potent antioxidant, anti-inflammatory, antihistamine, antiviral, immune-boosting, and other biological properties. Since 1977, many lab and animal studies, as well as a few human clinical studies and trials, have shown that quercetin works in multiple ways to help prevent or alleviate the symptoms of a variety of conditions, including:
  • Cancer
  • Canker sores
  • Heart disease
  • Herpes
  • Human Immunodeficiency Virus (HIV)
  • Nasal allergy relief
  • Respiratory infections

University of Maryland Med Center scientists have long considered quercetin, and other flavonoids contained in fruits and vegetables important in cancer prevention. Animal and test tube studies suggest that flavonoids have anti-cancer properties.
Also, Quercetin and other flavonoids have been shown in studies to inhibit the growth of cancer cells from breast, colon, prostate, ovarian, endometrial, and lung tumors and is more effective than resveratrol in terms of inhibiting tumor growth.

It is suggested to supplement with other Bioflavonoids such as Resveratrol, Soy Isoflavones, or green tea Catechins to increase the potency, and theoretically, obtain benefits at a reduced level of intake.

Scientific Support & Reference Citations