Component characterization of Zanthoxylum nitidum extract and its anti-colitis effect through regulating PPARγ/NF-κB/iNOS signaling pathway and gut microbiota

Qiang Lu; Xia Wen; Fan Yang; Haohui Chen; Cailan Li

doi:10.1016/j.intimp.2025.115165

Component characterization of Zanthoxylum nitidum extract and its anti-colitis effect through regulating PPARγ/NF-κB/iNOS signaling pathway and gut microbiota

Int Immunopharmacol. 2025 Jul 11:162:115165. doi: 10.1016/j.intimp.2025.115165. Online ahead of print.

Authors

Qiang Lu¹, Xia Wen², Fan Yang², Haohui Chen¹, Cailan Li³

Affiliations

¹ Department of Pharmaceutical Sciences, Zunyi Medical University, Zhuhai Campus, Zhuhai 519041, PR China.
² Department of Pharmacology, Zunyi Medical University, Zhuhai Campus, Zhuhai 519041, PR China.
³ Department of Pharmacology, Zunyi Medical University, Zhuhai Campus, Zhuhai 519041, PR China; Key Laboratory of Basic Pharmacology of Ministry of Education and Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Zunyi Medical University, Zunyi 563000, China; Key Laboratory of Basic Pharmacology of Guizhou Province and School of Pharmacy, Zunyi Medical University, Zunyi 563000, China. Electronic address: licailan@zmu.edu.cn.

PMID: 40651433
DOI: 10.1016/j.intimp.2025.115165

Abstract

Ulcerative colitis (UC) is a chronic, recurrent inflammatory disease of the gastrointestinal tract, for which there are currently no effective therapeutical targets or curative agents. Zanthoxylum nitidum (Roxb.) DC., known as "liangmianzhen" in China, is a woody liana plant belonging to the Rutaceae family. Its dried root is widely used as a traditional Chinese herbal medicine that possesses anti-inflammatory, antibacterial, analgesic, and gastrointestinal protective properties. However, its protective effect against UC is still unclassified. This study aims to investigate the active ingredients, therapeutic efficacy, and probable mechanism of Z. nitidum root in experimental UC. An ethanol extract of Z. nitidum root (ZNE) was prepared, and its chemical composition was characterized. A murine UC model was established via affording 3 % dextran sulfate sodium (DSS), a well-established method to induce colitis resembling human UC. Disease condition was monitored to assess the efficacy of ZNE. ELISA, qRT-PCR, immunohistochemistry, Western blotting and molecular docking were used to elucidate the potential mechanism of ZNE against UC. Additionally, bacterial 16S rRNA gene sequencing was used to assess changes in gut microbiota. Component characterization indicated that the main components of ZNE are alkaloids, including magnoflorine, diosmin, hesperidin, sanguinarine, nitidine chloride, chelerythrine, skimmianine, and L-sesamin. Animal experiment displayed that ZNE treatment prominently attenuated the manifestations of DSS-elicited colitis, reduced DAI scores and histological damage, which exhibited more effectiveness than positive drug 5-ASA. Furthermore, ZNE markedly decreased pro-inflammatory cytokine levels while enhancing anti-inflammatory factors. Mechanistically, ZNE remarkably regulated the PPARγ/NF-κB/iNOS signaling pathway by irritating PPARγ, inhibiting IκBα phosphorylation, and preventing NF-κB p65 nuclear translocation, thereby suppressing iNOS expression. However, the role of ZNE in alleviating UC and regulating PPARγ/NF-κB/iNOS signaling pathways was partially abolished by treatment with PPAR-γ antagonist GW9662, indicating that ZNE activated PPARγ to exert its activities. Molecular docking analysis revealed that the above eight alkaloids from ZNE demonstrated significant binding affinity to PPARγ by interacting with critical amino acid residues in its active site. Additionally, ZNE alleviates UC by restoring gut microbiota balance, specifically by promoting the proportion of beneficial bacteria such as Bacteroidetes, Porphyromonadaceae, Prevotellaceae and Akkermansia_muciniphila, while reducing the Firmicutes/Bacteroidetes ratio and the abundance of Proteobacteria, Enterobacteriaceae, Bacteroides, Bacteroides_acidifaciens and Escherichia. Correlation analysis results suggested that these altered bacteria are closely related to the colitis-related parameters. In conclusion, this study is the first to demonstrate that ZNE exerts significant protective effects against UC, and the main active ingredients of ZNE are alkaloids. Its anti-colitis mechanism involves modulation of the PPARγ/NF-κB/iNOS signal pathway and restoration of gut microbiota homeostasis.

Keywords: Component characterization; Gut microbiota; Inflammatory response; PPARγ/NF-κB/iNOS signal pathway; Ulcerative colitis; Zanthoxylum nitidum (Roxb.) DC..