Syringin ameliorates dextran sulphate colitis via alteration oxidative stress, inflammation NF-κB signalling pathway and gut microbiota.

Background: The objective of the current study was to investigate the potential effects of syringin against dextran sulphate colitis (DSS)-induced ulcerative colitis (UC) in mice.

Material and methods: In vitro study was performed on the RAW 264.7 cells and cytokines and inflammatory level were estimated. The oxidative stress, inflammatory cytokines, apoptosis and inflammatory parameters were estimated. The mRNA expression and faecal samples were estimated in the colon tissue.

Results: Syringin treatment enhanced the body weight, colon length and reduced the disease activity index (DAI), spleen index. Syringin treatment remarkably suppressed the level of nitric oxide (NO), myeloperoxidase (MPO), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) along with alteration of antioxidant parameters. Syringin treatment also altered level of cytokines in the serum and colon tissue; inflammatory parameters viz., platelet-activating factor (PAF), cyclooxygenase-2 (COX-2), prostaglandin (PGE₂), inducible nitric oxide synthetase (iNOS), nuclear factor κ-B (NF-κB); matrix metalloproteinases (MMP) level. Syringin significantly (p < 0.001) enhanced the level of nuclear factor erythroid 2-related factor (Nrf₂) and heme oxygenase-1 (HO-1). Syringin remarkably altered the relative abundance of gut microbiota like Firmicutes, Bacteroidetes, F/B ratio, Verrucomicrobia and Actinobacteria.

Conclusion: Syringin exhibited the protective effect against DSS-induced UC in mice via alteration of NF-κB signalling pathway.