Tannins from Sweet Chestnut (Castanea sativa)

Abstract

Extract of chestnut is a mixture of tannic and non-tannic components. The most common tannic components are the glycosides castalagin and vescalagin, which have a therapeutic effect. In conducted studies in vitro and in vivo, it was found that the tannin extract of chestnut has anti-diarrhoeal, astringent, antiviral, antimicrobial, antiprotozoal and anthelmintic properties. At the same time, it was found that the tannin extract of chestnut has anti-carcinogenic properties. Tannin interacts with the membrane structures of certain microorganisms, and thus decreases the permeability of the cell membrane. This antimicrobial activity is advantageous in terms of the action of antibiotics, because tannins only cause the inhibition of microflora growth but not its destruction. Ingested tannins at therapeutic concentrations (2-5%) cannot be absorbed and so cannot cause pharmacodynamic effects on the other organic systems. In the intestines, by means of hydrolysis, they are completely biotransformed into polyphenols (gallic, digallic and elastic acids) and glucose. In the urine, only the degradation products of tannin in the form of glucuronide can be identified. In therapeutic concentrations, tannins have an insignificant effect on the skin, while on mucous membranes they act astringently. At higher concentrations, tannins may lead to degradation of superficial, and even deeper layers of mucous membranes and granulation tissue. Given that they do not show teratogenic, mutagenic or carcinogenic effects, everything indicates that tannins should be more often and more extensively used as safe veterinary drugs.