Green synthesis and antimicrobial evaluation of Ag/TiO₂ and Ag/SeO₂ Core-Shell nanocomposites using r. Officinalis extract: A combined experimental and docking study

The escalating threat of antibiotic resistance necessitates the development of novel, sustainable antibacterial agents. This study investigates the potential of utilizing Rosmarinus officinalis leaf extracts to synthesize Ag/TiO₂ and Ag/SeO₂ nanocomposites. R. officinalis extract, a rich source of phenolic and flavonoid compounds, effectively and safely acts as a reducing and capping agent for the green synthesis of Ag/TiO₂ and Ag/SeO₂ nanocomposites. Characterization of nanocomposites revealed the nanoparticles’ nanoscale size, ranging from 43.34 to 96.58 nm for Ag/TiO₂ and 8.04 to 21.72 nm for Ag/SeO₂. Both types of nanoparticles exhibited a spherical morphology and distinct crystalline structure. The nanoparticles demonstrated significant antibacterial properties against multiple bacterial strains. The effective concentration for antibacterial activity was determined to be 30.99 mg/mL for Ag-TiO₂ and 32.41 mg/mL for Ag-SeO₂ nanoparticles. The surface charge of the nanoparticles was measured to be −14.0 mV for Ag-TiO₂ and −15.4 mV for Ag/SeO₂. Molecular docking simulations investigated the interactions between rosmarinic acid, its derivatives, and the antibiotic cefotaxime with a bacterial protein (e.g., DNA gyrase). These simulations provided insights into the distinct antibacterial mechanisms of these compounds. Briefly, this research highlights the potential of R. officinalis-derived nanocomposites as promising antibacterial agents. The eco-friendly synthesis and promising results pave the way for their development and application in medicine, biochemistry, and environmental fields.