Pre-clinical investigation of protective effect of nutraceutical D-glucosamine on TNBS-induced colitis

The level of precursors involved in the biosynthesis of glycosaminoglycan (GAG), glucosamine synthase, and N-acetyl glucosamine (NAG), are significantly reduced in inflammatory bowel disease (IBD). This results in deficient GAG content in mucosa, which eventually disrupt the gut wall integrity, provoking abnormal immunological responses. This is characterized by colossal liberation of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukins (ILs), and reactive oxygen species (ROS) provoking colonic inflammation. D-glucosamine (D-GLU) is reported to suppress oxidative stress, and pro-inflammatory cytokines and acts as a starting material for biosynthesis of NAG. The potential of D-GLU and its combination with mesalamine (5-ASA) was investigated in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-instigated IBD in Wistar rats.Standard and test drugs were given orally for 5 d to separate groups of rats. Colonic inflammation was evaluated by disease activity score rate (DASR), colon/body weight ratio, colon length, diameter, colon pH, histological injury, and score. Inflammatory biomarkers IL-1β, TNF-α, along with reduced glutathione (GSH), and malondialdehyde (MDA) were assessed.Combination of D-GLU + 5-ASA significantly ameliorated severity of colonic inflammation by lowering DASR (p < 0.001) and colon/body weight ratio (p < 0.001), restored the colonic architecture and suppressed the histopathological score (p < 0.001), along with the absence of major adverse reactions. The combination suppressed the levels of inflammatory markers (p < 0.001) and MDA (p < 0.001) while enhancing GSH level (p < 0.001).In comparison to individual 5-ASA and D-GLU, combination of drugs significantly diminished colitis severity through their combined anti-inflammatory and antioxidant effects by acting on multiple targets simultaneously. The combination holds remarkable potential in the management of IBD.