phenols of vegetable origin. Characteristic representatives of catechins are the stereoisomers catechin and epicatechin.
Catechins are colorless crystalline substances, often with a bitter, astringent taste. They are easily soluble in water and alcohol. Tannins are formed upon their polymerization. Catechins have been found in a number of edible fruits (apples, peaches, apricots, quinces, plums, and cherries) and berries (strawberries, currants, raspberries, gooseberries, and red bilberries). A large amount is present in the young shoots of the tea plant (as much as 20–25 percent of the dry weight), in catechu acacias, in grapes (primarily in the pits and skin), and in cocoa beans. The compounds are extracted from tea leaves on an industrial scale.
Catechins are highly active biologically. They regulate capillary permeability, increase the elasticity of capillary walls, and promote more efficient use of ascorbic acid by the organism. Therefore, catechins are among the substances that have vita-min-P activity, and they are used in the treatment of diseases connected with functional disorders of the capillaries and of edemas of vascular origin. Tea catechins have antimicrobial properties and are used in the treatment of dysentery. Oxidative conversions of catechins play an important role in food production technology, including the fermentation of tea, wine-making, and the preparation of cocoa.
M. N. ZAPROMETOV