Tannins microbial inhibition

N.A. 3-O-P-D-glucuronide, mucilage, tannins, flavones.103117 Treat skin irritation and bums, infused flower for gargle for sore throat and laryngitis. It is anti-irritant and used as a mild sun screen, inhibiting microbial growth. 

After the hides have been removed from the bathing wheel, they are placed in the tan pits to which at first is added solutions of tan liquor and then more concentrated solutions. These tan liquors contain all varieties of microbial life, but the tannin from the tan bark has an inhibitive action on the putrefactive organisms. 

In ruminants, the principal cause of bloat (a sometimes fatal condition of high rumen pressure) appears to be the formation of a stable foam in the reticulo-rumen (Reid et al., 1974). The foaming, which causes pressure retention, appears to be due to the soluble plant proteins in the rumen (Clark and Reid, 1974) and is prevented by protein precipitation with tannins (Jones et al., 1973). The production of gas by microbial fermentation is also inhibited. 

Several mechanisms have been proposed to explain the antimicrobial properties of tannins. The antimicrobial effects of phenolic compounds are probably related to the inhibition of bacterial enzymes, alterations in cell wall permeability, an increase in the hydrogen ion activity of the microbial environment, a reduction in the surface and/or interfacial tension and perhaps chelation of essential minerals, particularly iron with a concomitant impairment of the microbial oxidative metabolic system (Chung et al. 1998). The antimicrobial activities of tannins are ascribed to the interactions of goats tannins with the extracellular enzymes secreted and... 

Patra AK, Saxena J (2009) Dietary phytochemicals as rumen modifiers a review of the effects on microbial populations. Anton van Leeuwen 96 363-375 Patra AK, Saxena J (2010) A new perspective on the use of plant secondary metabolites to inhibit methanogenesis in the rumen. Phytochemistry 71 1198-1222 Patra AK, Saxena J (2011) Exploitation of dietary tannins to improve rumen metaboUsm and ruminant nutrition. J Sci Food Agric 91 24-37... 

Tannins can also affect the nitrogen and carbon cycles they can complex proteins or metallic ions and can present toxicity for microorganisms and inhibit enzymatic activities. In the majority of studies, mineralization of the nitrogen is decreased by the addition of tannins, while the effects on carbon mineralization remain more variable. By their characteristic link to proteins, tannins inhibit the microbial extracellular enz5mies and can also limit the available substrates for microbial growth. The difference in tannin content of the leaves seems to act on the aquatic macroinvertebrate communities using... 

---