Green synthesis of zinc oxide nanoparticles using Pulicaria undulata extract: Evaluation of antibacterial and larvicidal efficacy against Aedes aegypti

The present study reports the green synthesis and characterization of zinc oxide nanoparticles (ZnO NPs) using <i>Pulicaria undulata</i> extract and evaluates their larvicidal and antibacterial potential. UV-Visible spectroscopy confirmed ZnO NP formation by a sharp peak at 294 nm, indicating surface plasmon resonance and nanoparticle stability. Scanning electron microscopy (SEM) revealed irregular, agglomerated nanoparticles with heterogeneous morphology, while X-ray diffraction (XRD) confirmed a crystalline wurtzite hexagonal structure with high purity and crystallinity. Fourier-transform infrared spectroscopy (FTIR) identified hydroxyl, carboxylic, and Zn-O functional groups, highlighting the role of plant phytochemicals in nanoparticle stabilization. Histopathological analysis demonstrated significant tissue damage in <i>Aedes aegypti</i> larvae treated with ZnO NPs, including midgut disruption and muscular degeneration, suggesting strong larvicidal activity. Antibacterial assays against <i>Escherichia coli</i> and <i>Staphylococcus aureus</i> showed concentration-dependent zones of inhibition, with <i>S. aureus</i> exhibiting higher susceptibility. SEM images of bacterial cells post-treatment revealed severe morphological damage, including membrane rupture and shrinkage, confirming the antibacterial mechanism <i>via</i> structural disruption. Overall, the biosynthesized ZnO NPs exhibit promising eco-friendly properties with effective larvicidal and antibacterial activity, indicating their potential applications in mosquito vector control and antimicrobial therapeutics.