Intestinal anti-inflammatory activity of Sasa quelpaertensis leaf extract by suppressing lipopolysaccharide-stimulated inflammatory mediators in intestinal epithelial Caco-2 cells co-cultured with RAW 264.7 macrophage cells

Abstract

BACKGROUND/OBJECTIVES: Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, involves chronic inflammation of the gastrointestinal tract. Previously, Sasa quelpaertensis leaves have been shown to mediate anti-inflammation and anti-cancer effects, although it remains unclear whether Sasa leaves are able to attenuate inflammation-related intestinal diseases. Therefore, the aim of this study was to investigate the anti-inflammatory effects of Sasa quelpaertensis leaf extract (SQE) using an in vitro co-culture model of the intestinal epithelial environment. MATERIALS/METHODS: An in vitro co-culture system was established that consisted of intestinal epithelial Caco-2 cells and RAW 264.7 macrophages. Treatment with lipopolysaccharide (LPS) was used to induce inflammation. RESULTS: Treatment with SQE significantly suppressed the secretion of LPS-induced nitric oxide (NO), prostaglandin E2 (PGE(2)), IL-6, and IL-1 beta in co-cultured RAW 264.7 macrophages. In addition, expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and tumor necrosis factor (TNF)-alpha were down-regulated in response to inhibition of I kappa B alpha phosphorylation by SQE. Compared with two bioactive compounds that have previously been identified in SQE, tricin and P-coumaric acid, SQE exhibited the most effective anti-inflammatory properties. CONCLUSIONS: SQE exhibited intestinal anti-inflammatory activity by inhibiting various inflammatory mediators mediated through nuclear transcription factor kappa-B (NF-kappa B) activation. Thus, SQE has the potential to ameliorate inflammation-related diseases, including IBD, by limiting excessive production of pro-inflammatory mediators.