Cinnamon extract reduces symptoms, inflammatory mediators and mast cell markers in murine IL-10−/− colitis

Inflammatory bowel disease (IBD) shows an increasing prevalence and harm in western countries. Conventional therapies are associated with bad compliance and adverse side effects. Natural substances like cinnamon extract (CE) could be an additional therapy. We found recently that CE acts anti-inflammatory on mast cells - discussed of being relevant in IBD. Here, we analysed the effects of CE on murine IL-10−/− colitis as model for IBD. Mice were treated 12 weeks with or without CE in drinking water. Clinical scores and disease activity index were assessed. Colonic tissue samples were analysed for infiltration, tissue damage, bowel wall thickness, expression of pro-inflammatory mediators, mast cell proteases, tight junction proteins, and NF-κB signaling. Following treatment with CE, symptoms of murine colitis as well as increased infiltration of immune cells, tissue damage and bowel wall thickness in colon tissue of IL-10−/− mice were diminished significantly. MIP-2, TNF, IFNγ, CCL2, CCL3, CCL4 and IL-1β as well as MC-CPA, MCP-1 and MCP-4 were strongly upregulated in IL-10−/− mice compared to WT, but noteworthy not in CE group. Expression of tight junction proteins was not influenced by CE. Phosphorylation of IκB was slightly down-regulated in CE treated IL-10−/− mice compared to IL-10−/− controls. In summary, CE decreases inflammatory symptoms and expression of inflammatory markers in murine IL-10−/− colitis. CE has no influence on tight junction proteins, but seems acting via reducing pro-inflammatory mediators and recruitment of neutrophil granulocytes probably by inhibiting NF-κB signaling.