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Green synthesis of silver nanoparticles using salvia rosmarinus extract: Characterization, mechanistic antibacterial, antibiofilm, and in silico evaluation

Year: 2025

Type: article

Abstract: In this study, silver nanoparticles (AgNPs) were synthesized using Salvia rosmarinus (rosemary) extract and evaluated for their antibacterial and antibiofilm efficacy against Pseudomonas aeruginosa . The rosemary-mediated AgNPs (Rm-AgNPs) were characterized using ultraviolet–visible (UV–Vis) spectroscopy (peak at 430 nm), transmission electron microscopy (TEM, ∼31.34 nm), dynamic light scattering (DLS, 281.5 nm), Fourier transform infrared spectroscopy (FTIR), high-resolution X-ray diffraction (HR-XRD), and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDX), confirming successful biosynthesis, crystallinity, spherical morphology, and stability (zeta potential −21.35 mV). Rm-AgNPs exhibited significant antibacterial activity against P. aeruginosa , with a minimal inhibitory concentration (MIC) of 32.5 µg/mL, and pronounced antibiofilm effects, inhibiting biofilm by up to 65.68 % at 2xMIC. Mechanistic investigations demonstrated that Rm-AgNPs treatment resulted in a substantial increase in reactive oxygen species (ROS) production (3.48-fold increase at 2xMIC), glutathione depletion (21.62 %), and notable leakage of intracellular proteins (4352.38 µg/mL) and DNA (110.35 ng/µL), indicative of severe membrane damage and oxidative stress. Metabolite profiling of rosemary extract via UPLC-HRMS identified multiple bioactive compounds. Molecular docking studies revealed strong interactions between rosemary phytochemicals, notably Alnuside A (docking score −6.81 kcal/mol with LasI) and Umbelliferone (docking score −7.98 kcal/mol with WbpE), and key proteins involved in quorum sensing and biofilm formation. ADMET analysis confirmed good oral absorption, suitable lipophilicity, and low predicted toxicity for Umbelliferone and NP-014904. Toxicity assessments with ( Artemia salina ) revealed moderate toxicity of Rm-AgNPs, with an LC 50 value of 202.55 µg/mL. This study emphasizes the potential of AgNPs derived from S. rosmarinus as sustainable and effective agents against infections associated with biofilms and antimicrobial resistance.

Source: Industrial Crops and Products

DOI: 10.1016/j.indcrop.2025.122033