Intestinal anti-inflammatory effects of cinnamon extracts in a co-culture model of intestinal epithelial Caco-2 cells and RAW264.7 macrophages

Cinnamon is the bark of Cinnamomum japonicum SIEB, which possesses anti-microbial, anti-tyrosinase, and antioxidant activities. However, studies on the intestinal health benefits of cinnamon are scarce. Therefore, we were aimed at assessing the potential anti-inflammatory action of cinnamon extracts in a cellular model of intestinal inflammation. Cinnamon extracts were prepared using hot water extract and 70% ethanol extract. Prior to inducing inflammation, co-cultured Caco-2 cells with RAW264.7 cells were treated with the cinnamon extracts. Lipopolysaccharide (LPS) was treated to induce inflammation in RAW264.7 cells. Compared to LPS-treated groups, the cells treated with cinnamon extracts maintained high transepithelial electrical resistance and decreased tight junction permeability, similar to that shown by control Caco-2 cells. In addition, cinnamon extract-treated cells showed decreased levels of inflammatory cytokines, namely nitrite (NO), PGE₂, interleukin (IL)-6, IL-8, and TNF-α. These results show that cinnamon may serve as a probable agent for the development of functional supplements for maintenance of gastrointestinal health.