Quercetin is an important member of a large group of plant compounds called flavonoids, once thought to be vitamins.
Quercetin is a very highly concentrated form of Bioflavonoids derived from citrus fruit.
Citrus Bioflavonoids provide natural antiviral, anti-inflammatory and anti-allergy properties.
Quercetin appears to help fight a host of disorders, from asthma to cancer to heart disease. As an antioxidant, it combats the destructive "free radical" molecules that play a part in many diseases. Among people with high dietary intakes of quercetin and other major flavonoids, studies show lower rates of stomach, lung, pancreatic, and breast cancers.
Quercetin offers a variety of potential therapeutic uses. Of note is that quercetin seems to work better when used in conjunction with bromelain, a digestive enzyme found in pineapples, particularly for allergies and inflammation.
Quercetin is considered a phytoestrogen (i.e., a plant substance with similar functions as that of estrogen ). Some phytoestrogens are believed also to have antiestrogenic effects that might lead to reduced risks of certain cancers.
In a double-blind trial, 67% of people taking quercetin had an improvement of prostatitis symptoms, compared with a 20% response rate in the placebo group.
Again, quercetin didn't help everyone, and in those it did help not everyone had complete resolution of symptoms.
Quercetin, which is primarily found in apples, onions, and black tea, is a type of flavonoid (plant pigment) that serves as a building block for other members of the flavonoid family.