Quercetin is a plant-sourced antioxidant compound for the maintenance of good health suitable for the dynamic and demanding world we share. Quercetin is widely distributed in the plant kingdom and is the most abundant of the flavonoid molecules. It is found in many foods including apples, onions, berries, and Brassica-type vegetables. It?s also present in medicinal botanicals which include Ginkgo biloba and Hypericum perforatum (St. John?s wort). Quercetin is recognized among the key components of the medicinal activity of these plants and has been shown in experimental studies to have numerous effects on the body. All flavonoids have the same basic chemical structure: A three-ringed molecule with hydroxyl (OH) groups attached. Many variations can occur, giving rise to a large and diverse range of flavonoids. Quercetin is an organic compound similar to many therapeutic flavonoids, including rutin, isoquercetin, and hyperoside. It has been researched for beneficial effects on human health, many of which are accredited to its antioxidant action. Each vegetable capsule contains: Quercetin 500 mg. Other ingredients: Vegetable magnesium stearate and silicon dioxide in a non?GMO vegetable capsule composed of vegetable carbohydrate gum and purified water.