Toxicity of Tannic Compounds to Microorganisms

Abstract

The inhibition of microorganisms by tannic compounds is due to hydrogen bonding with vital proteins such as enzymes. An important factor governing the toxicity of tannic compounds to microorganisms is the tannin polymer size. The strongest inhibition occurs with oligomers, since these are large enough for effective crossbridged hydrogen bonds with proteins, yet small enough for penetration to the sensitive sites within microorganisms. Tannins are particularly vulnerable to polymerization reactions in air; therefore, in practice, the toxicity of tannins is quite dynamic. Polymerization can result in the toxification of tannin monomers and in the detoxification of tannin oligomers.