Polyphenols are a group of chemical substances found in plants, characterized by the presence of more than one phenol unit or building block per molecule. Polyphenols are generally divided into hydrolyzable tannins (gallic acid esters of glucose and other sugars) and phenylpropanoids, such as lignins, flavonoids, and condensed tannins. Chemistry Classification and Nomenclature The division of polyphenols into tannins, lignins, and flavonoids's derived from the variety of simple polyphenolic… (More on Polyphenol)