Pomolic Acid from the Dong Botanical Drug Madeng'ai Suppresses TNF-α-Induced Inflammatory Response in RA-HFLS by Inhibiting NF-κB Signaling Pathway Activation.

Abstract

Objective: This study aimed to investigate whether pomolic acid (PA), a predicted bioactive metabolite of the Dong botanical drug Madeng'ai (MDA), suppresses inflammatory cytokine expression by inhibiting nuclear factor-κB (NF-κB) pathway activation in a tumor necrosis factor-α (TNF-α)-induced human rheumatoid arthritis fibroblast-like synoviocyte (RA-HFLS) model. Methods: PA content in MDA from different regions and harvest years was quantified via High-Performance Liquid Chromatography (HPLC). Network analysis was employed as a hypothesis-generating tool to predict potential targets and pathways, followed by molecular docking to validate the binding affinity of PA to core targets of the NF-κB pathway, and ADMET prediction to evaluate its pharmacokinetic properties and safety profile. The RA-HFLS inflammatory model was induced by TNF-α. Cell viability and inflammatory cytokine secretion were assessed using Cell Counting Kit-8 (CCK-8) and enzyme-linked immunosorbent assay (ELISA). NF-κB signaling pathway activation and downstream gene expression were examined by Western blot and reverse transcription quantitative polymerase chain reaction (RT-qPCR), respectively. Results: HPLC analysis revealed that MDA samples from Guizhou harvested in 2019 contained the highest PA content (0.1117 mg/g). Network analysis predicted the NF-κB signaling pathway as a candidate mechanism underlying PA's potential anti-inflammatory effects. Molecular docking showed that PA stably bound to IKKβ, p65, and IκBα, while ADMET prediction indicated favorable intestinal absorption, low drug-drug interaction risk, and good genetic safety, albeit with potential hepatotoxicity and reproductive toxicity risks. In the TNF-α-induced RA-HFLS model, PA dose-dependently inhibited abnormal cell proliferation and significantly reduced the secretion of pro-inflammatory cytokines TNF-α and interleukin-6 (IL-6). Mechanistic studies indicated that PA suppressed the activation of the NF-κB signaling pathway, thereby downregulating the mRNA expression of inflammatory genes such as IL-6, TNF-α, and interleukin-1β (IL-1β). Conclusions: PA, a bioactive metabolite of the Dong botanical drug MDA, may inhibit NF-κB signaling pathway activation, thereby downregulating TNF-α-induced inflammatory cytokine expression in RA-HFLS, demonstrating its in vitro anti-inflammatory potential.