Plant Polyphenols: Structure, Occurrence and Bioactivity

Main dietary plant polyphenols are grouped into structural types and their occurrence in most common foods and beverages is briefly described. The major groups of plant polyphenols which are examined include flavonols, flavones, flavanones, isoflavones, anthocyanins, proanthocyanidins and flavanols. The current evidence on the absorption and the metabolism of each group is discussed. The biochemical and pharmacological activities of plant polyphenols are summarized, including antioxidant and anti-radical activity, chelation of metal ions, modulation of some enzymes activity, anticarcinogenic, antiatherosclerotic, anti-inflammatory, spasmolytic, hepatoprotective, antiviral, antimicrobial and oestrogenic activity, and inhibition of histamine release. An overview on the epidemiological evidence linking the intake of plant polyphenols and diminished risk of chronic diseases is also included.