Phytosynthesis of zinc oxide nanoparticles using Thymus vulgaris leaf extract: characterization and dual biological efficacy

Zinc oxide nanoparticles (ZnO NPs) were green-synthesized using aqueous leaf extract of Thymus vulgaris as a reducing and stabilizing agent. Comprehensive characterization using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM)- Energy Dispersive X-ray Spectroscopy (EDX), and Fourier Transform Infrared (FTIR) confirmed the formation of pure, hexagonal wurtzite ZnO NPs with an average crystallite size of 13.1 nm. The findings confirmed the formation of crystalline hexagonal ZnO with moderate colloidal stability. The average hydrodynamic diameter was 243.24 nm, attributed to particle agglomeration and phytochemical capping effects. Biologically, the ZnO NPs exhibited dose-dependent antibacterial activity against Gram-positive bacteria and significant cytotoxicity toward MCF-7 breast cancer cells (IC₅₀ = 34.36 μg/mL) . Mechanistic investigations revealed enhanced intracellular reactive oxygen species (ROS) generation, Zn 2+ ion release, and caspase-3 activation, indicating ROS-mediated apoptotic cell death. This study highlights the dual antibacterial and anticancer potential of T. vulgaris -mediated ZnO NPs and provides mechanistic insights into their bioactivity, supporting their promise as multifunctional green nanomaterials. • Phytochemical capping by thymol and carvacrol enhances nanoparticles bioactivity. • Achieved crystalline ZnO NPs with primary size of ~13 nm via eco-friendly route. • Exceptional MCF-7 cytotoxicity with IC₅₀ of 34.36 μg/mL via ROS-mediated apoptosis. • Controlled Zn 2+ release profile links structure to multifunctional efficacy. • Predictive synthesis–function framework for plant-mediated nanotherapeutics.