Quercetin

A flavonoid found in a variety of foods, such as buckwheat, apples, citrus fruits and tea.  Quercetin is an antioxidant, and may have anti-inflammatory and anti-tumor activity.  Quercetin is sometimes added to bodybuilding supplements, as it may inhibit certain enzymes responsible for metabolizing testosterone and other drugs/nutraceuticals (cytochrome P-450).

Chemical name(s): 3,3′,4′,5,7-pentahydroxyflavone; 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-chromen-4-one