Rhamnogalacturonan polysaccharide inhibits inflammation and oxidative stress and alleviates visceral pain

Rhamnogalacturonan (RGal) is a polysaccharide isolated from Acmella oleracea that ameliorates the intestinal barrier in an ulcerative colitis model induced by dextran sulfate sodium (DSS) and in Caco-2 cells. Here we investigate if RGal could reduce visceral pain, inflammation, oxidative stress and gastrointestinal dysmotility. Acetic acid, capsaicin or mustard oil were used to assess the visceral pain in normal mice. Ulcerative colitis was induced with DSS and RGal (10 mg/kg) was given orally for 7 days. RGal reduced abdominal contortions, cell migration, capsaicin, and mustard oil-induced visceral nociception. RGal reduced the visceral hypersensitivity, myeloperoxidase, lipid hydroperoxide and restored the glutathione, glutathione S-transferases, and superoxide dismutase levels and gastrointestinal motility, and protected the colonic epithelium and enteric neurons. RGal attenuates inflammation and consequently pain and intestinal motility; and could be a promising candidate for the treatment of ulcerative colitis. However, studies regarding the mechanism of action of RGal merited exploring further.