Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using <i>Citrus sinensis</i> Leaf Extract for Antifungal Activity Against <i>Macrophomina phaseolina</i>

ABSTRACT Zinc oxide nanoparticles (ZnO‐NPs) were synthesized by an environmentally benign and cost‐effective method using Citrus sinesis (orange) leaves aqueous extract, and tested for antifungal activity against Macrophomina phaseolina . Comprehensive characterization was performed using UV–vis spectroscopy, zeta potential, particle size analysis (PSA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and x‐ray diffraction (XRD) techniques. UV–vis analysis confirmed nanoparticle fabrication with an absorption peak at 281 nm, while PSA showed an average particle size of 75 nm. FTIR study demonstrates broad absorption peaks at 3496 and 2325 cm −1 , corresponding to hydroxyl (OH −1 ) and carbon dioxide (CO 2 ) groups, respectively. A band at 1580 cm −1 indicates the carbonyl (C═O) functional group; stretching vibrations observed at 715 cm −1 confirm the formation of ZnO‐NPs. The crystalline structure was confirmed by the XRD analysis with 71.5 nm crystallite size, and SEM images revealed a coarse, grainy surface morphology. Antifungal assays displayed a complete fungal growth inhibition (100%) at 0.144 and 0.288 mg/mL. These results highlight the antifungal potential of ZnO‐NPs, supported by stability, favorable cost, and reusability for practical application.