Vicoa indica, renowned for its medicinal properties, has recently attracted attention for its potential role in the eco-friendly synthesis of zinc oxide nanoparticles (ZnONPs) using its leaf extract. In this study, the biosynthesis of ZnONPs was thoroughly characterized through a range of analytical and biological methods. UVV is spectroscopy confirmed successful nanoparticle synthesis, with a prominent absorption peak at 374 nm. FTIR analysis identified seven key functional groups involved in the synthesis process, while X-ray diffraction (XRD) revealed the crystalline nature of the nanoparticles. Scanning electron microscopy (SEM) imaging displayed spherical-shaped ZnONPs, and energy-dispersive X-ray analysis (EDAX) confirmed the presence of zinc (Zn) and oxygen (O) in the particles. The ZnONPs exhibited significant antibacterial properties, with the largest inhibition zone (12 mm) against Staphylococcus aureus. In vitro antioxidant assays, including DPPH, ABTS, and SOD tests, demonstrated robust radical scavenging activity. Furthermore, ZnONPs displayed promising anticancer effects, reducing cell viability by 86.61 in A549 lung cancer cell lines, indicating substantial cytotoxicity. This study underscores the sustainable production of ZnONPs from V. indica leaf extract, presenting promising applications in the fields of biology and environmental science. The findings highlight the potential of V. indica-derived nanoparticles to address critical health and environmental challenges. © 2025 Elsevier B.V., All rights reserved.