Flavonoids: Dietary Occurrence and Health Benefits

Flavonoids comprise the most common group of plant polyphenols and provide much of the flavor and color to fruits and vegetables. More than 5000 different flavonoids have been described. The six major subclasses of flavonoids include flavonols, flavonones, flavones, flavanols, flavan-3-ols and isoflavones according to the positions of the substitutes present on the parent molecule. Over 4,000 flavonoids have been identified, many of which occur in fruits, vegetables and beverages (tea, coffee, beer, wine and fruit drinks). The flavonoids have aroused considerable interest recently because of their potential beneficial effects on human health. They have been reported to have antiviral, antiallergic, antiplatelet, antiinflammatory, antitumor and antioxidant activities. Some studies support a protective effect of flavonoid consumption in cardiovascular disease and cancer.