Abstract
The word “tannin” has loosely been used to define two different classes of chemical compounds of mainly phenolic nature: hydrolyz-able tannins and condensed tannins. The former, including chestnut, myrobolans (Terminalia and Phyllantus tree species), and dividivi (Caesalpina coraria) extracts, are mixtures of simple phenols, such as pyrogallol and ellagic acid, and of esters of a sugar, mainly glucose, with gallic and digallic acids.