Quercetin:3,3',4',5,7-Pentahydroxyflavone dihydrate:Introduction and Its Benefit Applications.

Introduction:Quercetin.

Quercetin:3,3',4',5,7-Pentahydroxyflavone dihydrate CAS:6151-25-3 EINECS ELINCS No.:204-187-1 Chem IUPAC Name:2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one bioflavonoid anti-tumour photo picture image Quercetin is a bioflavonoid similar to rutin. Human cell culture studies with quercetin demonstrated its capability to inhibit the release of histamines. Quercetin is the most abundant of the flavonoids. Quercetin belongs to the flavonoids family and consist of 3 rings and 5 hydroxyl groups. Quercetin is also a building block for other flavonoids. Quercetin occurs in food as a aglycone (attached to a sugar molecule). Only a small percentage of the ingested quercetin will get absorbed in the blood.

Quercetin is a flavonoid compound found in the bark and rinds of many plants and fruits.The estimated human normal dietary intake of quercetin, primarily as glycosides, is 0.1-0.2 mg/kg.Quercetin is present in much greater amounts in nutritional supplements. Quercetin is carcinogenic in male rats, inducing renal adenomas when fed at 2,000 mg/kg. Quercetin has been reported to inhibit phosphodiesterases of both cGMP and cAMP.

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

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."

High dietary intake of fruits and vegetables is associated with reduction in cancer, and some scientists[who?] suspect quercetin may be partly responsible. Research shows that quercetin influences cellular mechanisms in vitro and in animal studies, and there is limited evidence from human population studies that quercetin may reduce the risk of lung cancer.

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 (in vitro), quercetin produces changes that are also produced by compounds that cause cancer (carcinogens), 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).