Effects of Polyphenols from Oat and Oat Bran on Anti-Inflammatory Activity and Intestinal Barrier Function in...

Oats and oat bran are rich in dietary fiber, polyphenols and other phytochemicals.

In this study, we evaluated the phytochemical content and established LPS-induced RAW 264.7 macrophage inflammation and DSS-induced Caco-2 cell inflammation models to investigate the anti-inflammatory activities of oat and oat bran polyphenols and their molecular mechanisms.

The results showed that oat and oat bran polyphenols (free and bound polyphenols) enhanced phagocytosis, decreased the expression of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), reduced the production of NO and ROS, increased the mitochondrial membrane potential, and reduced the inflammatory cytokines (TNF-α, IL-1β, and IL-6) at the gene level in the RAW 264.7 macrophage inflammation model induced by LPS expression, thus demonstrating strong anti-inflammatory activity. In Caco-2 cells, oat and oat bran polyphenols pretreatment attenuated the DSS-induced decrease in trans-epithelial electron resistance value, increased tight junction protein expression, and reduced cell permeability in Caco-2 cell monolayers, which in turn reduced inflammatory damage in the organism.

In summary, the present study not only reveals the mechanism by which oat and oat bran polyphenols inhibit macrophage inflammation and impairment of intestinal barrier function at defined concentration in vitro, but also highlights potential for oat bran as a functional food.