Anti-inflammatory effect of lentil hull (Lens culinaris) extract via MAPK/NF-κB signaling pathways and effects of digestive products on intestinal barrier and inflammation in Caco-2 and Raw264.7 co-culture

The polyphenol-rich lentil hulls are the by-product of lentils hulling process. In this manuscript, in vitro digestion, Caco-2 cell monolayer and Caco-2/RAW264.7 cell co-culture model were established to explore their antiinflammatory mechanism, absorption of digestive products (RLD), and impact on the intestinal barrier. Results shown that high dose RLE and GLE could significantly inhibit the secretion of NO (30.23% and 31.08%, respectively), IL-6 (81.48% and 56.82%, respectively) and IL-1 beta (88.05% and 91.67%, respectively), and down regulate the protein and mRNA expression of iNOS (56.46% and 45.69%, respectively) and COX-2 (76.53% and 46.65%, respectively), and inhibit the activation of MAPK and NF-kappa B signaling pathways. Polyphenols can be released from lentil hulls and protocatechuic acid glycoside derivative has the highest content (2205.09 +/- 7.02 mu g/g DW). Digestive products can be absorbed by intestine to maintain intestinal barrier and play antiinflammatory effect. Above all, lentil hulls may be a potentially valuable functional dietary resource.

Automated summary

In this study, the anti-inflammatory mechanism and impact on the intestinal barrier of lentil hulls were investigated. It was found that high doses of lentil hulls could inhibit the secretion of inflammatory mediators and downregulate the expression of inflammatory genes, as well as inhibit the activation of signaling pathways. Lentil hulls contain polyphenols, and the digestive products can be absorbed by the intestine and exert anti-inflammatory effects.