Study on the anti‐inflammatory effect of stachyose by inhibiting TLR4/NF‐κB signalling pathway in vitro and in vivo

This study aimed to explore the anti-inflammatory effect of stachyose, a tetrasaccharide extracted from Stachys sieboldii Miq. A lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages model and a dextran sodium sulfate (DSS)-induced ulcerative colitis BALB/C mice model was used to assess the anti-inflammatory effect of stachyose both in vitro and in vivo. The levels of nitric oxide (NO) and cytokines (interleukin-1β, interleukin-6 and tumour necrosis factor-α) were detected using enzyme-linked immunosorbent assay methods; moreover, haematoxylin-eosin staining was used to observe changes in intestinal morphology of mice. In addition, the possible mechanisms were explored by reverse transcription-polymerase chain reaction and western blot. Results showed that stachyose and four other oligosaccharides (galacto-oligosaccharides, xylo-oligosaccharides, inulin and resistant dextrin) inhibited NO secretion and the production of pro-inflammatory cytokines in LPS-stimulated RAW264.7 macrophages in a dose-dependent manner, whereas stachyose was most effective in vitro. In mice, different doses of stachyose significantly alleviated the symptoms of DSS-induced ulcerative colitis and stachyose also significantly inhibited the production of inflammatory cytokines and myeloperoxidase in vivo. In addition, our findings illustrated that stachyose inhibited expression of toll-like receptor 4 (TLR4) and suppressed the phosphorylation of nuclear factor (NF)-κB p65 both in vitro and in vivo. Taken together, results demonstrated that stachyose exerted anti-inflammatory effect through inhibition of the TLR4/NF-κB signalling pathway.