Quercetin and hesperidin are members of a family of naturally occurring chemicals produced in plants known as flavonoids. According to the University of Maryland School of Medicine, flavonoids have a number of health-promoting qualities. They are antioxidant, anti-inflammatory and have a tonifying effect on connective tissue. Generally found in dark berries, these chemicals also may help reduce the severity of allergic reactions and strengthen the integrity of venous and endothelial membranes. Although research has suggested that bioflavonoids such as quercetin and hesperidin have considerable therapeutic potential, the findings are only preliminary. More studies are needed to determine what quercetin and hesperidin may effectively treat.
Anti-inflammatory Activity
Several studies have found that some flavonoids have anti-inflammatory properties. Quercetin, through both its direct antioxidant activity and through the inhibition of enzymes like lipoxygenase and other inflammatory mediators, works as a systemic anti-inflammatory agent. Like many pharmaceutical ant-inflammatory drugs, hesperidin inhibits cycloxegenase, or COX. Hesperidin also affects inflammatory pathways by blocking a number of other enzymes, including lipoxygenase, HMG-CoA reductase and phospholipase A2.
Antihistamine Activity
In alternative medicine, high doses of quercetin have for years been used to suppress allergy symptoms. Quercetin has specifically been found to inhibit the release of histamine by basophils and mast cells, the cells responsible for nasal allergy symptoms. Although hesperidin has not traditionally been used as an anti-histamine, research has suggested that it may be a useful treatment for hay fever and other allergies. Like quercetin, hesperidin appears to inhibit histamine release from mast cells.
Erythema and Dermatitis
The University of Maryland Medical Center recommends flavonoid complexes that contain hesperidin and quercetin as a complement to conventional treatment for dermatitis and erythema. Both of these flavonoids are believed to have a mild anti-inflammatory activity, helping to reduce redness and discomfort. They are particularly recommended when sufferers from erythema develop increased photosensitivity, as high doses of flavonoids may afford some protection from sun damage.
Vascular Health
Butcher's broom, a plant used for centuries as a treatment for hemorrhoids, varicose veins and general venous insufficiency, is particularly rich in hesperidin. According to Memorial Sloan-Kettering Cancer Center, hesperidin is the phytochemical most likely to be responsible for its beneficial effects on the vascular system.
