Abstract
Quercetin is widely distributed in the plant kingdom and is the most abundant of the flavonoid molecules. It is found in many often-consumed foods, including apple, onion, tea, berries, and brassica vegetables, as well as many seeds, nuts, flowers, barks, and leaves. It is also found in medicinal botanicals, including Ginkgo biloba, Hypericum perforatum (St. John’s Wort), Sambucus canadensis (Elder), and many others. It is often a major component of the medicinal activity of the plant, and has been shown in experimental studies to have numerous effects on the body.