DESCRIPTION

Quercetin occurs as a yellow or greenish yellow crystalline powder. It is obtained from aqueous extraction of the quercetin glycoside, rutin, from various materials that include immature sun-dried fava d'anta beans, uncaria leaves, onions, apples, and leaves of ginkgo biloba. Crude quercetin aglycone is produced via acid hydrolysis of rutin, with subsequent neutralization followed by multiple purification steps to yield purified quercetin. Quercetin is soluble in glacial acetic acid and in aqueous alkaline solutions; it is slightly soluble in alcohol, and insoluble in water.