Polysaccharide from Scutellaria barbata D. Don attenuates inflammatory response and microbial dysbiosis in ulcerative colitis mice

This study aimed to evaluate the effect of polysaccharides from Scutellaria barbata D. Don (PSB) on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in C57BL/6 mice. PSB was isolated, and its chemical composition was preliminarily identified. The average molecular weight of PSB was 1.25 × 104 Da and it was mainly comprised of arabinose, galacturonic acid, galactose, glucose, and glucuronic acid in molar ratios of 1.00:2.09:4.52:4.73:4.90. PSB (25 and 50 mg/kg) and sulfasalazine (200 mg/kg) significantly relieved weight loss and symptoms and alleviated colonic pathological injury in mice with UC. In addition, PSB decreased the levels of inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, and IL-18 in the colon and suppressed DSS-induced activation of the nuclear factor kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) pathways. The improvement in the abundance of several bacterial genera, such as the Lachnospiraceae_NK4A136_group, Ruminococcus, Bacteroides, Parasutterella, and Eisenbergiella might be closely related to the reduction in the intestinal inflammatory response after PSB treatment. These results revealed that PSB could potentially be utilized to treat UC and other diseases associated with an imbalance in the intestinal flora.