Gut Microbiota Remodeling Mediates the Therapeutic Effects of a Plant-Based Medicine on DSS-Induced Ulcerative Colitis in Mice via the Butyrate-SVCT1-Vitamin C Axis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with a rising global incidence in recent years. Dengzhan shengmai (DZSM), a plant-based formulation clinically used in the management of cerebrovascular diseases, possesses documented anti-inflammatory and antioxidant properties; however, its effects on UC are unclear. In this study, we investigated the therapeutic potential and underlying mechanism of DZSM in a dextran sulfate sodium (DSS)-induced murine colitis model. Our results showed that DZSM significantly alleviated UC-related parameters. Mechanistically, DZSM remodeled gut microbiota dysbiosis, specifically enriching the abundance of short-chain fatty acid (SCFA)-producing bacteria and elevating colonic levels of SCFAs. Notably, butyrate upregulated the expression of the sodium-dependent vitamin C transporter 1 (SVCT1) in colonic epithelial cells, thereby enhancing cellular vitamin C (VitC) uptake. The accumulated VitC synergized with butyrate to exert potent antioxidant and anti-inflammatory effects, further reinforcing epithelial barrier function. Importantly, fecal microbiota transplantation (FMT) confirmed that the protective effects of DZSM on UC were achieved by modulating gut microbiota, at least partially. Collectively, our findings demonstrate for the first time that DZSM alleviates DSS-induced colitis in mice through a novel butyrate-SVCT1-VitC axis driven by gut microbiota remodeling, providing new mechanistic insights into the microbiota-dependent efficacy of plant-based medicine.