PLANT TANNINS AND SOME MECHANISMS OF THEIR PHARMACOLOGICAL PROPERTIES

Abstract

Tannins are found in many parts of plants (fruits, bark, roots, leaves). In the chemical classification, they belong to water-soluble polyphenols. There are 2 classes of tannins: hydrolyzable (formed by polyatomic alcohol) and non-hydrolyzable (formed by condensation of phenolic compounds). Tannin derived from plants belongs to pharmacopoeia preparations. Most often in pharmacology it is used as an astringent and local anti-inflammatory agent. In addition, there is information about its antioxidant and anti-cancer properties of tannin. The mechanisms by which almost all the properties of both hydrolyzable and condensed tannins are realized are based on the regulation of the activity of the corresponding key enzymes; in most cases, this may be their activation to trigger a cascade of biochemical reactions. In addition, condensed tannins, due to their weak ability to dissolve, are able to precipitate and inactivate other substances (for example, cholesterol, external and internal antigens) due to the binding ability of gallic and tannic acids with biological molecules and prevent their excessive accumulation in the body. Some plants (for example, legumes, raspberries, persimmons, bananas) contain tannic acids with neuroprotective properties and antidepressant effects, the mechanism of which is associated with a decrease in the activity of acetylcholinesterase, as well as the effect on the activity of Na + / K+-ATPase and Ca2+- ATPase. Extracts of tannins have a hypoglycemic effect due to the inactivation of α-amylases, lipases and glucosidases; this property can be used to develop drugs for the prevention and treatment of diabetes mellitus.