Integrating Metabolomics and Transcriptomics Reveals the Multi-Target Mechanisms of Fermented Portulaca oleracea L. (Purslane) in Attenuating Acute Diarrhea

Background: Current understanding of the biotransformation of bioactive compounds in Portulaca oleracea through probiotic fermentation remains limited, and the anti-diarrheal mechanisms of the resulting fermented products have yet to be fully elucidated. Methods: In this exploratory study, we employed untargeted metabolomics together with a senna-induced acute diarrhea mouse model to investigate P. oleracea co-fermented with Lactiplantibacillus plantarum and Bacillus subtilis. Results: Metabolomic profiling identified 220 metabolites significantly altered by fermentation, predominantly comprising increased levels of lipids, phenylpropanoids, and polyketides. Compared with the unfermented P. oleracea control, fermented P. oleracea (FP) effectively reduced the diarrhea index, lowered serum levels of inflammatory cytokines (IL-1β, IL-6, TNF-α) and neurotransmitters (5-HT, substance P), and restored Na+/K+ balance as well as ileal histomorphology. Transcriptomic analysis and RT-qPCR validation further demonstrated that FP modulated the expression of genes involved in focal adhesion, PI3K-Akt, cGMP-PKG, and mineral absorption pathways. Conclusions: Fermented P. oleracea (FP) alleviates acute diarrhea through multi-target mechanisms. Notably, fermentation endows P. oleracea with markedly superior intestinal protective effects relative to the unfermented counterpart. These findings provide preliminary experimental evidence supporting the potential of fermented P. oleracea as a candidate for intestinal protective functional food research.