Natural Products: Experimental Efficient Agents for Inflammatory Bowel Disease Therapy

Inflammatory bowel disease (IBD) is a chronic, elusive disorder resulting in relapsing inflammation of intestine with incompletely elucidated etiology, whose two representative forms are ulcerative colitis (UC) and Crohn's disease (CD). Accumulating researches have revealed that the individual genetic susceptibility, environmental risk elements, intestinal microbial flora, as well as innate and adaptive immune system are implicated in the pathogenesis and development of IBD. Despite remarkable progression of IBD therapy has been achieved by chemical drugs and biological therapies such as aminosalicylates, corticosteroids, antibiotics, anti-tumor necrosis factor (TNF)-α, anti-integrin agents, etc., healing outcome still cannot be obtained, along with inevitable side effects. Consequently, a variety of researches have focused on exploring new therapies, and found that natural products (NPs) isolated from herbs or plants may serve as promising therapeutic agents for IBD through antiinflammatory, anti-oxidant, anti-fibrotic and anti-apoptotic effects, which implicates the modulation on nucleotide- binding domain (NOD) like receptor protein (NLRP) 3 inflammasome, gut microbiota, intestinal microvascular endothelial cells, intestinal epithelia, immune system, etc. In the present review, we will summarize the research development of IBD pathogenesis and current mainstream therapy, as well as the therapeutic potential and intrinsic mechanisms of NPs in IBD.