Quercetin

Quercetin a flavonol, is a plant-derived flavonoid found in fruits, vegetables, leaves and grains. It also may be used as an ingredient in supplements, beverages or foods.

Quercetin is a powerful antioxidant. It is also a natural anti-histamine, and anti-inflammatory. Research shows that quercetin may help to prevent cancer, especially prostate cancer.Quercetin's antihistamine action may help to relieve allergic symptoms and asthma symptoms. The anti-inflammatory properties may help to reduce pain from disorders such as arthritis. Men who are concerned about prostate problems would also benefit from quercetin. Quercetin may also help reduce symptoms like fatigue, depression and anxiety.

Quercetin is a naturally-occurring polar auxin transport inhibitor.

• black and green tea (Camellia sinensis; 2000–2500 mg/kg),
• capers (1800 mg/kg),
• lovage (1700 mg/kg),
• apples (44 mg/kg),
• onion, especially red onion (1910 mg/kg) (higher concentrations of quercetin occur in the outermost rings),
• red grapes,
• citrus fruit,
• tomato (more in organically grown)
• broccoli and
• other leafy green vegetables, and a number of berries, including raspberry, bog whortleberry (158 mg/kg, fresh weight), lingonberry (cultivated 74 mg/kg, wild 146 mg/kg), cranberry (cultivated 83 mg/kg, wild 121 mg/kg), chokeberry (89 mg/kg), sweet rowan (85 mg/kg), rowanberry (63 mg/kg), sea buckthorn berry (62 mg/kg), crowberry (cultivated 53 mg/kg, wild 56 mg/kg)