TNF and inflammatory bowel disease: Correspondingly, some studies reported that mesalazine (5-aminosalicylic acid, 5-ASA), which has been widely used to treat IBD in clinical settings [5], may play a therapeutic role by reducing the expression levels of pro-inflammatory cytokines including interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α) in colon tissues [6, 7].