Sustainable valorization of <i>Nicotiana glauca</i> biomass for the green fabrication of multifunctional ZnO nanoparticles

The sustainable valorization of plant biomass for the fabrication of advanced functional materials represents a promising strategy for greener materials development. In this study, zinc oxide nanoparticles (ZnONPs) were synthesized via a green route using an ethanolic extract of Nicotiana glauca, an abundant plant species in arid regions, as a natural reducing and stabilizing agent. This approach avoids hazardous chemicals and promotes the use of renewable biological resources in nanomaterial production. Structural analyses confirmed the formation of single-phase hexagonal wurtzite ZnO with an average crystallite size of 26.77 nm, determined by Rietveld refinement. UV–Vis spectroscopy showed a characteristic absorption band at 360 nm, while FTIR results indicated the involvement of plant-derived phytochemicals in nanoparticle nucleation and surface stabilization. SEM–EDX analysis verified nanostructured morphology and high elemental purity. Although the crude extract exhibited strong antioxidant activity, the biosynthesized ZnONPs demonstrated enhanced antibacterial performance (minimum inhibitory concentration <25 μg/mL against Escherichia coli and Staphylococcus aureus) and significant antiproliferative activity towards HeLa cells (IC50 = 24.28 ± 0.35 μg/mL). These findings demonstrate a sustainable pathway for converting renewable plant metabolites into high-value multifunctional metal oxide nanomaterials aligned with green chemistry principles.