The aqueous extract of Reynoutria japonica ameliorates damp-heat ulcerative colitis in mice by modulating gut microbiota and metabolism

J Ethnopharmacol. 2024 Nov 6;338(Pt 1):119042. doi: 10.1016/j.jep.2024.119042. Online ahead of print.

Abstract

Ethnopharmacological relevance: Reynoutria japonica has been utilized as a potential treatment for gastrointestinal disorders in Traditional Chinese Medicine (TCM). However, the efficacy and mechanism of its aqueous extracts on damp-heat ulcerative colitis (UC) remains unclear.

Aim of the study: Investigating the modulating effect of aqueous extracts of Reynoutria japonica (AERJ) on gut microbiota and fecal metabolisms in mice with damp-heat UC.

Methods: UPLC-Q-TOF-MS was used for the compositional characterization of the AERJ. BALB/c mice were used as a model for establishing damp-heat UC. Hematoxylin-eosin (HE) staining and immunohistochemistry (IHC) method were conducted to observe the pathological changes in the colon. Enzyme-linked immunosorbent assay (ELISA) was used for quantitative analysis of relevant physiological indicators. 16 S rRNA gene sequencing was employed to detect changes in gut microbiota in mice. In addition, metabolomics analysis was performed on mice feces. Finally, the aforementioned indicators underwent correlation analysis.

Results: Seven components within the AERJ were qualitatively identified by chromatographic analysis. The AERJ alleviated the symptoms in damp-heat UC mice, suppressed the expression of inflammatory factors, attenuated mucosal damage, improved water-fluid metabolism, and regulated the gut microbiota composition. Differential metabolites in feces were mainly enriched in the amino acid metabolic pathway, and AERJ was able to upregulate the expression levels of short chain fatty acids (SCFAs). Meanwhile, the present study found that physiological indicators were significantly correlated with both the gut microbiota and SCFAs.

Conclusion: AERJ showed significant therapeutic effects on damp-heat UC mice, and its mechanism of action may be related to altering the composition of gut microbiota, regulating amino acid metabolism and the content of SCFAs and thus restoring the mucosal integrity and inflammatory response.

Keywords: Damp-heat ulcerative colitis; Gut microbiota; Non-targeted metabolomics; Reynoutria japonica; Short-chain fatty acids.