Gut barrier reinforcement by Gegen Qinlian decoction mitigates irinotecan-induced enterotoxicity

Abstract Objective: Irinotecan (CPT-11)-induced delayed diarrhea is a major dose-limiting toxicity that restricts its clinical application. Gegen Qinlian Decoction (GQD), a traditional Chinese herbal formula, has shown potential in alleviating CPT-11-induced intestinal injury, but its underlying mechanisms remain incompletely understood. This study aimed to systematically elucidate the protective effects and mechanisms of GQD against CPT-11 enterotoxicity. Methods: We integrated ultra-performance liquid chromatography-quadrupole-Orbitrap-mass spectrometry (UPLC-QE-Orbitrap-MS) for chemical profiling of GQD, along with network pharmacology, molecular docking, and molecular dynamics simulation to identify key bioactive constituents and potential targets. Furthermore, a CPT-11-treated mouse model and Caco-2 cell monolayers were employed to evaluate the effects of GQD. Quantitative proteomics and untargeted metabolomics were applied to explore pathway alterations, and biochemical, histological, and functional analyses were conducted to assess inflammatory responses, oxidative stress, barrier integrity, and drug transporter activity. Results: A total of 65 compounds were identified in GQD, with 17 prioritized as putative bioactive constituents. Network analysis highlighted the IL‑6/IL‑22/STAT3 inflammatory axis and ABC transporter pathways as central mechanisms. In vivo, GQD administration ameliorated diarrhea, preserved colonic architecture and mucin production, reduced pro-inflammatory cytokines and oxidative stress, and restored expression of tight-junction proteins. Multi-omics integration showed that GQD counteracted CPT-11-induced dysregulation in complement/coagulation cascades and metabolic pathways, while enriching ABC transporter-related functions. In Caco-2 monolayers, GQD promoted SN-38 efflux, upregulated MDR1 and MRP2 expression, and decreased intracellular SN-38 accumulation. Consistent with this, GQD enhanced colonic clearance of SN-38 in mice. Conclusions: GQD protects against CPT-11-induced enterotoxicity primarily through two mechanisms: suppressing the pro-inflammatory IL-6/IL-22/STAT3 signaling pathway and enhancing the epithelial efflux of SN-38 via upregulation of ABC transporters. These findings provide a mechanistic basis for the potential use of GQD as an adjuvant therapy to mitigate intestinal toxicity during irinotecan chemotherapy.