other names
Flavin meletin

Quercetin 200px-Quercetin

The American Cancer Society says that while quercetin "has been
promoted as being effective against a wide variety of diseases,
including cancer," and "some early lab results appear promising, as of
yet there is no reliable clinical evidence that quercetin can prevent
or treat cancer in humans." In the amounts consumed in a healthy diet,
quercetin "is unlikely to cause any major problems or benefits."

Adequate dietary intake of fruits and vegetables may reduce the risk of cancer. Research shows that quercetin influences cellular mechanisms in vitro and, in animal studies, there is evidence from human population studies that quercetin may, in a very limited fashion, reduce the risk of certain cancers.
Some researchers believe quercetin should not be used by healthy
people (for prevention) until it can be shown that quercetin doesn't
itself cause cancer. In laboratory studies of cells , quercetin produces changes that are also produced by compounds that cause cancer , but these studies don't report increased cancer in animals or humans. The U.S. Food and Drug Administration has not approved any health claims for quercetin.There is current early-stage clinical research on quercetin addressing safety and efficacy against sarcoidosis , asthma and glucose absorption in obesity and diabetes (February 2009).

Quercetin 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 rutinose , respectively. Quercetin is classified as IARC group 3 (no evidence of carcinogenicity in humans). and