BACKGROUND:Ulcerative colitis (UC) is a chronic inflammatory disease of the gastrointestinal tract. Despite the availability of traditional clinical treatments, their limitations highlight the need for alternative therapies derived from natural products that offer both strong efficacy and minimal side effects. Chaenomeles speciosa (Sweet) Nakai (CS), edible and medicinal fruit traditionally used to treat gastrointestinal disorders, has shown potential in UC management. However, the specific phytochemicals and mechanisms through which CS exerts its therapeutic effects remain poorly understood.
PURPOSE:This study aimed to isolate and identify the bioactive compounds in CS, screen for the most potent compounds, especially chlorogenic acid derivatives, and assess their efficacy in treating UC. Additionally, we sought to investigate the underlying mechanisms of action.
METHODS:The anti-inflammatory components from CS were separated and identified using various chromatographic techniques and nuclear magnetic resonance spectroscopy. Compounds with potential anti-inflammatory activity were screened using the NO release assay and enzyme linked immunosorbent assay (ELISA). Potential therapeutic pathways were explored through network pharmacology. In vivo, the therapeutic effect of the target compound, 3-O-(E)-caffeoylquinic acid n-butylester (BE), on UC was evaluated by monitoring body weight, disease activity index (DAI), colon length, histopathological scores, tight junction protein expression, and inflammatory marker transcript levels. Moreover, surface plasmon resonance (SPR) assay, gene knockdown, molecular docking, molecular dynamics simulations, quantitative Real-Time reverse transcription (qRT-PCR), and western blot (WB) analysis were employed to validate therapeutic mechanisms. The effects of BE on the intestinal microbiota and its associated metabolites in UC mice were further characterized through metagenomic sequencing and Gas Chromatography-Mass Spectrometry (GC-MS).
RESULTS:After preliminary activity investigation of isolated phenolic compounds based on ELISA, chlorogenic acid and its derivatives (BE and the novel 3-O-(Z)-caffeoylquinic acid n-butylester) were selected for CCK-8 assay and NO release inhibition. Among them, BE exhibited the most potent anti-inflammatory effects and was chosen for further intervention in UC mice. Network pharmacology analysis predicted that the NF-κB signaling pathway is a potential mechanism underlying the therapeutic effects of BE in UC. In vivo, BE effectively restored body weight and colon length, reduced DAI and histopathological scores, preserved the intestinal epithelial barrier, and decreased the expression of inflammatory biomarkers. WB and qRT-PCR experiments validated the BE attenuates inflammation by affecting the NF-κB/NLRP3 signaling pathway. SPR assay, gene knockdown, molecular docking, and molecular dynamics simulations revealed that BE inhibits activation of NLRP3 inflammasome by binding to NLRP3. Additionally, metagenomic sequencing and GC-MS showed that BE significantly reduced the relative abundance of Escherichia coli, while increasing Eubacterium and Roseburia sp. 1XD42-69. BE also restored short-chain fatty acid levels.
CONCLUSION:Our findings suggest that BE, derived from CS, demonstrates promising therapeutic efficacy against UC. It exerts potent anti-UC effects by targeting NLRP3 and affecting the NF-κB/NLRP3 signaling axis to inhibit activation of NLRP3 inflammasome and remodeling intestinal homeostasis.
