Biogenic Fabrication of Nanoparticles With Rhododendron arboreum: A Multifunctional Platform With Antibacterial,...

Plant-mediated nanotechnology offers a sustainable alternative to conventional nanoparticle synthesis by reducing reliance on hazardous chemicals and energy-intensive processes. Zinc sulfide nanoparticles (ZnS NPs) were selected for this study due to their wide bandgap, tunable optical properties, and promising biomedical potential compared to other semiconductor nanoparticles. Rhododendron arboreum flower extract, rich in flavonoids, terpenoids, and phenolic compounds, was chosen as a natural reducing and stabilizing agent to enable eco-friendly nanoparticle fabrication. We hypothesized that this phytochemical-rich extract could facilitate the green synthesis of ZnS NPs with distinctive physicochemical features and enhanced biological activity.

ZnS NPs were synthesized via a Soxhlet extract-assisted method and characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and UV-visible spectroscopy.

The nanoparticles exhibited a cubic phase structure with a crystallite size of 2.28 nm, an optical bandgap of 2.8 eV, and peak absorption at 356 nm. SEM analysis revealed irregular morphology. Biological assays demonstrated that the ZnS NPs possessed superior antibacterial activity compared to the flower extract alone, with lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi. The nanoparticles also exhibited significant anti-inflammatory properties by inhibiting protein denaturation of egg albumin protein at different concentrations (6.75-100 µg/mL) with inhibition values ranging from about 60% to 97%. It also showed cytotoxic and pro-apoptotic effects against HCT116 cancer cell lines.

These findings highlight how green synthesis using R. arboreum extract not only provides an eco-friendly route for ZnS NP fabrication but also yields nanoparticles with promising antibacterial, anti-inflammatory, and anticancer potential.