Irritable bowel syndrome (IBS), a functional gastrointestinal disorder characterized by impaired digestive function, predominantly presents as the diarrhea-predominant irritable bowel syndrome (IBS-D). Current therapeutic strategies for IBS-D primarily aim to restore intestinal barrier integrity and regulate secretory homeostasis. However, progress in therapeutic development has been limited by an incomplete understanding of the microbial sensing mechanisms that govern intestinal barrier dynamics. This study investigates the therapeutic efficacy of paeoniflorin (PF) in IBS-D treatment and elucidates its underlying mechanisms. Through comprehensive preclinical evaluation, PF administration significantly ameliorated diarrheal symptoms and psychiatric comorbidities in IBS-D rats, concomitant with structural restoration of intestinal villi and functional recovery of secretory regulation. Mechanistically, PF exerted its therapeutic effects through gut microbiota-dependent attenuation of secretory immunoglobulin A (sIgA) hypersecretion. Notably, fecal microbiota transplantation and depletion experiments revealed that PF-mediated intestinal barrier repair and secretory normalization were operated through Lachnospiraceae bacterium modulation. Functional characterization demonstrated that Lachnospiraceae bacterium alleviated IBS-D pathophysiology by enhancing tight junction assembly and facilitating mucin maturation. Furthermore, mechanistic analysis identified FoxO3a signaling as a pivotal mediator of the intestinal protection conferred by Lachnospiraceae bacterium. Collectively, this study not only establishes PF as a promising therapeutic candidate but also uncovers novel microbial-epithelial crosstalk mechanisms, highlighting the translational potential of probiotic-based interventions and bioactive compounds for intestinal disorders. These findings provide clinically relevant insights for the development of targeted therapeutics for IBS-D.

Lablab purpureus (L.) Sweet (L. purpureus) has been reported to alleviate diarrhea, although the precise mechanism remains unclear. This study identified the primary active components of L. purpureus utilizing ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). A rhubarb-induced diarrhea model in rats was utilized to assess the therapeutic efficacy of L. purpureus. Alterations in gut microbiota and fecal metabolism were analyzed via 16S rDNA analysis and targeted metabolomics. Flora elimination and fecal transplantation techniques were employed to deepen understanding of the role of intestinal flora in L. purpureus treatment. The study findings indicated that the main constituents of L. purpureus included trigonelline, piperidinic acid, and L-(–)-malic acid, among others. L. purpureus treatment significantly alleviated all diarrhea symptoms in rats, encompassing reduced fecal water content, weight loss, shortened colon length, diminished histological damage, and decreased inflammatory factors. Furthermore, L. purpureus significantly enhanced the expression of tight junction markers and restored the dysregulated intestinal flora in diarrheic rats by increasing Prevotella and reducing Lactobacillus. Additionally, the production of propionic acid and other short-chain fatty acids (SCFAs) increased in diarrheic rats treated with L. purpureus, suggesting a substantial alteration in the intestinal environment. Crucially, the protective efficacy of L. purpureus diminishes in the absence of gut flora. Subsequent fecal transplantation tests demonstrated that feces from the L. purpureus-treated group alleviated rhubarb-induced diarrhea, emphasizing the pivotal role of gut microbiota in the antidiarrheal efficacy of L. purpureus. In conclusion, our findings elucidate the underlying mechanisms of L. purpureus’ antidiarrheal action and its beneficial impact on intestinal microflora. Moreover, these results provide compelling evidence supporting the therapeutic use of L. purpureus for the treatment of diarrhea and its associated complications.

Ulcerative colitis (UC) is a common infl ammatory disease of the gastrointestinal tract. Traditional Chinese medicine (TCM) has long been used in Asia as a treatment for UC and Puerariae Radix (PR) is a reliable anti-diarrheal therapy. The aims of this study were to investigate the protective effect of PR using the dextran sulfate sodium salt (DSS)-induced UC model in mice and identify molecular mechanisms of PR action. The chemical constituents of PR via ultra-performance liquid chromatography/tandem mass spectrometry and identifi ed potential PR and UC targets using a network pharmacology (NP) approach were obtained to guide mouse experiments. A total of 180 peaks were identifi ed from PR including 48 flavonoids, 46 organic acids, 14 amino acids, 8 phenols, 8 carbohydrates, 7 alkaloids, 6 coumarins and 43 other constituents. NP results showed that caspase-1 was the most dysregulated of the core genes associated with UC. A PR dose of 0.136 mg/g administered to DSS treated mice reversed weight loss and decreased colon lengths found in UC mice. PR also alleviated intestinal mucosal shedding, infl ammatory cell infi ltration and mucin loss. PR treatment suppressed upregulation of NOD-like receptor protein 3 (NLRP3), cysteinyl aspartate-specific proteases-1 (caspase-1), apoptosis-associated speck-like (ASC) and gasdermin D (GSDMD) at both the protein and mRNA expression levels. The addition of a small molecule dual-specifi city phosphatase inhibitor NSC 95397 inhibited the positive effects of PR. These results indicated that PR exerts a protective effect on DSS-induced colitis by inhibiting NLRP3 infl ammasome activation in mice.