Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications.
Flavonoids are an important class of pigments, with variable phenolic structures naturally found in fruit and also in vegetables.
This class of naturally occurring polyphenolic compounds which cannot be synthesized by humans possesses a series of biological properties, acting on biological systems as antioxidants. Many flavonoids are shown to have antioxidative activity, free-radical scavenging capacity, coronary heart disease prevention, and anti-cancer activity, while some flavonoids exhibit potential for anti–human immunodeficiency virus functions.
Flavonoids also act as anti-inflammatory, and anti-tumoral agents, affecting capillary permeability and acting as exogenous antioxidants. Research on flavonoids received an added impulse with the discovery of the low cardiovascular mortality rate and also prevention of CHD.
Flavonoids capture and neutralize the oxidative agents, and quench free radicals, inhibiting several enzymes (ciclo-oxigenase, lipo- oxigenase, NADPH-oxidase, xantine-oxidase, fosfolipase) and stimulating enzymes with antioxidant activity (such as catalase and superoxide dismutase).
Flavonoid in fruits: antioxidant activities and health benefits 
