Bioinformatic analysis and experimental validation of ursolic acid's effects on Staphylococcus aureus-induced osteomyelitis

Osteomyelitis (OM), particularly methicillin-resistant Staphylococcus aureus (MRSA)-induced OM, remains a serious clinical challenge due to complex pathogenesis and rising antibiotic resistance. This study aimed to elucidate the therapeutic mechanism of ursolic acid (UA) against MRSA-induced OM using integrated network pharmacology, bioinformatics, and experimental validation. Through target prediction and multi-database mining, we identified 57 common targets of UA and OM. ML algorithms, including Least Absolute Shrinkage and Selection Operator (LASSO) and random forest, pinpointed three core genes: Neutrophil Elastase (ELANE), Lactoferrin (LTF), and S100A12. Enrichment analyses revealed significant involvement in neutrophil extracellular trap (NET) formation, inflammatory response, and immune regulation. Molecular docking and dynamics simulations confirmed stable binding between UA and ELANE. In vitro, UA exhibited antibacterial activity against clinical MRSA isolates (MIC = 16–64 μg/mL) and showed synergistic effects with Penicillin (FICI = 0.125–0.5). These results demonstrate that UA combats OM through immunomodulation, anti-inflammatory actions, and direct antibacterial activity, providing a foundation for its use as an adjuvant therapy against MRSA-related OM.