The Cerium oxide nanoparticles (CeO2 NPs) are prepared through green synthesis by using the Artabotrys hexapetalus leaf extracts. X-ray diffraction studies proved that synthesized CeO2 NPs exhibited cubic structure. SEM images taken for CeO2 NPs exhibited mesh like structure. EDAX analysis was used to identify the elemental compositions. Various functional groups were confirmed by FT-IR spectrum. UV–Vis spectra shows the direct band gap at 3.15 eV for CeO2 NPs. The antibacterial activity studies were done using K. pneumonia, S. aureus, S. dysenteriae and E. coli bacterial strain for CeO2 NPs. Cytotoxic effects of the CeO2 NPs were observed in cultured (MCF-7) human breast cancer cell line. © 2022 Elsevier B.V., All rights reserved.