Polyphenols in Fruits and Vegetables and Its Effect on Human Health

Polyphenols represent a group of chemical substances common in plants, structurally characte-rized by the presence of one or more phenol units. Polyphenols are the most abundant antioxi-dants in human diets and the largest and best studied class of polyphenols is flavonoids, which in-clude several thousand compounds. Numerous studies confirm that they exert a protective action on human health and are key components of a healthy and balanced diet. Epidemiological studies correlate flavonoid intake with a reduced incidence of chronic diseases, such as cardiovascular disease, diabetes and cancer. The involvement of reactive oxygen species (ROS) in the etiology of these degenerative conditions has suggested that phytochemicals showing antioxidant activity may contribute to the prevention of these pathologies. The present review deals with phenolic compounds in plants and reports on recent studies. Moreover, the present work includes informa-tion on the relationships between the consumption of these compounds, via feeding, and risk of disease occurrence, i.e. the effect on human health. Results obtained on herbs, essential oils, fro