Paliurus ramosissimus extract partially ameliorates AOM/DSS-induced colitis-associated colorectal cancer in mice: insights from transcriptomic and gut microbiota analyses.

Paliurus ramosissimus (PR) is a traditional folk medicinal plant recorded in Zhonghua Bencao (Chinese Materia Medica) and local medicinal records. In this study, Paliurus ramosissimus extract (PRex) was defined as an ethanol extract prepared from PR leaves. PR leaves have traditionally been used for heat-clearing and detoxification and for relieving swelling and pain. These traditional uses are closely related to inflammation-associated conditions. Because colitis-associated colorectal cancer (CAC) is characterized by chronic intestinal inflammation and mucosal injury, PR provides an ethnopharmacological rationale for evaluating PRex in an experimental CAC model. This study aimed to evaluate the protective effects of PRex in an AOM/DSS-induced CAC mouse model and to explore whether PRex-related phenotypic changes are associated with PPAR-related metabolic pathways and gut microbiota alterations. An AOM/DSS-induced CAC mouse model was established. The main mechanistic analysis included the Control, Model, and PRex 820 mg/kg groups, while Wuwei Kushen and Aspirin were used as pharmacodynamic reference groups for phenotypic evaluation. Betulinic acid was used as a single-marker quality-control compound for HPLC-ELSD-based batch quality control of PRex. General condition, disease activity index (DAI), colon length, histopathological changes, and PCNA expression were evaluated. RNA-seq and 16S rRNA sequencing were performed to characterize host transcriptomic and gut microbiota changes. qRT-PCR and Western blotting were used for preliminary molecular assessment, and external GEO datasets were analyzed to provide contextual evidence for candidate gene expression and co-expression patterns. HPLC-ELSD analysis showed that the betulinic acid content in this batch of PRex was 63.6 mg/g. PRex was associated with partial phenotypic improvement, including increased colon length and reduced PCNA-positive proliferative activity. However, the total histopathological injury score showed only a non-significant decrease compared with the Model group. Transcriptomic analysis identified PRex-associated opposite-direction genes enriched mainly in metabolism-related pathways, including the PPAR signaling pathway, retinol metabolism, and glycolysis/gluconeogenesis. 16S rRNA sequencing showed that PRex treatment was associated with shifts in gut microbiota composition and PICRUSt2-predicted functional profiles. Exploratory comparison suggested a possible overlap between host transcriptomic pathways and predicted microbial functional pathways. qRT-PCR preliminarily supported the expression trends of PPARα, CD36, FABP4, and PCK1, while Western blotting provided supportive semi-quantitative information. PRex was associated with partial phenotypic improvement in AOM/DSS-induced CAC mice, mainly reflected by increased colon length and reduced PCNA-positive proliferative activity, whereas the total histopathological injury score was not significantly reduced. Transcriptomic analysis, 16S rRNA sequencing, and preliminary molecular assessment suggested that PRex intervention was associated with changes in PPAR-related metabolic pathways and gut microbiota profiles. PPARα, CD36, FABP4, and PCK1 may represent candidate molecules associated with PRex treatment. However, these findings should be interpreted as exploratory and hypothesis-generating, and further dose-response, toxicological, pharmacokinetic, and causal validation studies are required.