Biogenic Synthesis of Cerium Oxide Nanoparticles: Characterization, Biological Activities and Their Corrosion Inhibition Properties

ABSTRACT Cerium oxide nanoparticles (CeO 2 NPs) were synthesized via a green and eco‐friendly method using Parkia biglandulosa leaf extract, which acted as both a reducing and stabilizing agent. The synthesized CeO 2 NPs exhibited a cubic fluorite crystal structure and predominantly spherical morphology, with particle sizes ranging from 10 to 12 nm. Antibacterial studies demonstrated notable activity against Lactobacillus acidophilus , Staphylococcus albus , and Streptococcus mutans , with the highest inhibition zone (32 mm) observed against S. mutans (Ce‐3). The anticancer activity assessed against MCF‐7 breast cancer cells demonstrated an IC 50 value of 43.13 μg/mL (Ce‐3). Antioxidant assays, including DPPH, ABTS, and hydroxyl radical scavenging, exhibited IC 50 values of 202.47, 219.77, and 193.05 μg/mL, respectively, indicating strong free radical scavenging potential. Additionally, corrosion resistance studies of CeO 2 NP‐coated mild steel in 3.5% NaCl solution revealed a maximum inhibition efficiency of 95.44% (Ce‐3), as confirmed by electrochemical impedance spectroscopy. Overall, these findings demonstrated the multifunctional efficacy of P. biglandulosa derived CeO 2 NPs for biomedical and industrial applications.