Rhamnogalacturonan rich fractions isolated from Saururus chinensis alleviate ulcerative colitis via regulation of MAPK/NF-κB pathway and tight junction

BACKGROUOND/OBJECTIVES: Saururus chinensis has been used as a traditional medicinal herb in many Asian countries such as Republic of Korea, Japan, and China.Previous studies on their pharmacological effects against anti-cancer, anti-oxidant, and anti-inflammation have mainly dealt with low-molecular-weight compounds, including flavonoids, saponins, and polyphenols.Nevertheless, the polysaccharide fraction of S. chinensis has received limited scholarly attention, and investigations regarding its effect on ulcerative colitis (UC) remain inconclusive.The present study was aimed to investigate effects of rhamnogalacturonan (RG) rich fraction (SCPE-II) isolated from S. chinensis on anti-UC.MATERIALS/METHODS: SCPE-II was isolated from S. chinensis using hot water extraction, ethanol precipitation, enzymatic hydrolysis, and gel filtration chromatography.SCPE-II was characterized by chemical properties, Fourier transform infrared spectroscopy, Congo red reaction, and methylation analysis.The anti-UC effects of the SCPE-II were preliminarily investigated in vitro using interleukin (IL)-1β-induced inflammatory Caco-2 cells.The preventive effects of polysaccharides on UC in vivo were evaluated in a dextran sulfate sodium (DSS)-induced UC mice model.RESULTS: The SCPE-II was characterized as a typical RG type polysaccharide.In addition, tight junction (TJ) imbalance and inflammatory cytokines in IL-1β-induced inflammatory epithelial cells was inhibited by SCPE-II.Moreover, SCPE-II suppressed various clinical symptoms in DSS-induced UC mice.These preventive effects were strongly correlated with the regulation of inflammatory cytokine, immunoglobulin, mitogen-activated protein kinase, nuclear factor kappa B, TJ, short chain fatty acid.CONCLUSION: Consequently, the present finding strongly suggests that SCPE-II isolated from S. chinensis is an effective ingredient for preventing UC.