Enhancement of Epithelial Tight Junctions By Nutraceuticals

Abstract

Using various epithelial cell culture models, the nutraceuticals zinc, quercetin, indole, resveratrol and glutamine have been shown to enhance tight junction barrier function. We show that their action is specific to the epithelial model being acted upon. Some increase transepithelial resistance. Some decrease paracellular D‐mannitol leak. Some do both. This depends upon the compound and the specific epithelial cell model. The structural effects of the nutraceuticals are likewise specific to the compound in question and the epithelial model, in terms of which tight junctional proteins are being up‐ or down‐regulated. Certain combinations of nutraceuticals can exhibit additive or even synergistic effects. The medical implications of these barrier‐enhancing nutraceuticals in various disease states are discussed.