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

Cerium oxide nanoparticles (CeO₂ 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 CeO₂ 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 IC₅₀ value of 43.13 μg/mL (Ce-3). Antioxidant assays, including DPPH, ABTS, and hydroxyl radical scavenging, exhibited IC₅₀ values of 202.47, 219.77, and 193.05 μg/mL, respectively, indicating strong free radical scavenging potential. Additionally, corrosion resistance studies of CeO₂ 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 CeO₂ NPs for biomedical and industrial applications.