Intestinal toxicity evaluation of Polygala total saponins in mice according to toxicological evidence chain (TEC) concept

BackgroundPolygalae Radix (PR), a widely used tranquilizing traditional Chinese medicine, is limited by gastrointestinal adverse effects. The Polygala total saponins (PTS) are identified as its major toxic constituents.MethodsTo clarify PTS toxicity and enrich its toxic mechanism, this study conducted four key steps: first, observing toxicity manifestations in ICR male mice and collecting serum/tissue samples post-administration; second, obtaining toxicity evidence via histopathological examination and serum biochemical indicators; third, detecting fecal microbial structure and metabolite types using 16S rRNA sequencing and metabolomics after PTS exposure; fourth, uncovering potential toxic mechanisms through transcriptomic analysis.ResultsThree days after PTS administration (i.g., 120 and 240 mg/kg/d), the mice were confirmed to have intestinal damage. Key mechanisms of PTS-induced intestinal toxicity included digestion-absorption disorders, inflammation, intestinal barrier injury, and gut microbiota dysbiosis-the latter closely linked to weight loss and barrier damage. Specifically, PTS upregulated arachidonic acid metabolism, downregulated metabolites (5,7-Dihydroxyisoflavone, Tyrosol, Glycitein, maltotetraose, N-acetylhistamine, taurocholic acid), DEGs (Ifi27l2b, Ctrl), and microbiota (Dactylosporangium, Saccharopolyspora, Iamia, Cellvibrio) to trigger inflammation and impair digestive-absorptive functions.ConclusionThis study interprets the mechanism of intestinal toxicity of PTS from the perspectives of metabolites, DEGs, and microbiota. This helps us refine the toxicological evidence chain (TEC) of PTS and further understand its toxicity mechanism.