Sustainable biogenic synthesis of cerium oxide nanoparticles (CeO2 NPs) using Cinnamomum verum bark: An in vitro physicochemical and biological assessment

Green synthesized inorganic nanoparticles are gaining attention as an eco-friendly and sustainable biomaterial in biomedical applications due to the limitations of conventional therapeutics. In this investigation, the cerium oxide nanoparticles (CeO₂ NPs) were synthesized using Cinnamomum verum bark extract and characterized for physicochemical and biological properties. The methanolic bark extract was initially assessed to confirm various phytoconstituents’ presence and, act as a reducing agent in synthesis. Furthermore, CeO₂ NPs were synthesized cost-effectively and further confirmed for the maximum wavelength between 242 and 292 nm; distinct peak at 854.71 cm-¹ further attributed to Ce-O and Ce-O-Ce vibration bonds, confirmed the formation of CeO2 NPs. The average crystalline size from XRD study confirmed 4.18 nm particle, -18.7 ± 5.25 mV of zeta potential, snowflakes-like shape, and average particle diameter of 19.53 ± 0.49 nm using HR-TEM analysis. The oxidation profiling assay confirmed that CeO₂ NPs possess anti-oxidant and pro-oxidant properties, including a maximum (99.47 ± 16.43%) scavenging of ferric ions. Additionally, the anti-inflammatory study indicated 70.41 ± 0.25% of protein denaturation and significant zone of inhibition (22.0 ± 0.25 mm) against Bacillus subtilis compared to other microorganisms. The cytotoxicity and cell proliferation evaluation in NIH3T3 fibroblast cells indicated significant cytoproliferative (118.44 ± 3.81%) nature, implying their potential contribution to tissue regeneration and wound healing. Thus, this preliminary investigation revealed that the potential physicochemical and biological activities of CeO₂ NPs, which required further assessment through preclinical and clinical validations.