Green synthesis of PbO–Fe3O4 magnetic nanocomposite using Peganum harmala L. extract for antimicrobial applications

The rise of antimicrobial resistance necessitates the development of novel therapeutic agents. This study reports a novel, eco-friendly green synthesis of lead oxide-magnetite (PbO-Fe 3 O 4 ) nanocomposites using Peganum harmala extract as a bioreducing and capping agent. Comprehensive characterization (XRD, FTIR, VSM, SEM-EDX, BET) confirmed the formation of a stable, crystalline, hard ferromagnetic nanocomposite after calcination at 600°C. The PbO-Fe 3 O 4 nanocomposite demonstrated superior, broad-spectrum antimicrobial activity against Acinetobacter baumannii , methicillin-resistant Staphylococcus aureus (MRSA), Candida albicans , and C. tropicalis compared to PbO alone. This enhanced efficacy was quantitatively confirmed by a two-fold reduction in minimum inhibitory concentration (MIC) values for both MRSA (0.156 mg/mL) and A. baumannii (0.039 mg/mL). Time-kill kinetics demonstrated sustained inhibition of MRSA growth over the 24-hour incubation period. The enhanced antimicrobial activity may be attributed to ROS-related mechanisms and the unique physicochemical properties of the PbO–Fe 3 O 4 nanocomposite, as suggested by previous studies. This study demonstrates the successful green synthesis of a PbO–Fe 3 O 4 nanocomposite with promising antimicrobial properties for environmental and surface-coating applications.