Antioxidant and Cholinesterase Inhibitory Activities of Zinc Oxide Nanoparticles Biosynthesized from Neem Leaf Extract
DOI:
https://doi.org/10.33003/fjs-2026-1019-6185Keywords:
Green synthesis, Zinc oxide nanoparticles, Azadirachta indica, Antioxidant, Cholinesterase inhibition, NeuroprotectionAbstract
Green metal oxide nanoparticles has emerged as bioactive nanomaterials with broad therapeutic potential. In this study, zinc oxide nanoparticles biosynthesised using Azadirachta indica (neem) leaf extract (AIZnoNPs) were evaluated for their in vitro antioxidant capacity and cholinesterase inhibitory activity. X-ray diffraction analysis of AlZnONPs revealed a hexagonal wurtzite crystal structure and an average crystallite size of 16.8 nm. Dynamic Light Scattering results showed a gradual decrease in particle size of highly monodisperse particles with a polydispersity index of less than 0.3. The surface area of smaller particles was found to be relatively high from the Brunauer- Emmett- Teller analysis. The complete preparation and characterization report of AlZnONPs is currently under review and not detailed here. Antioxidant activity was assessed using DPPH, ABTS, ferric reducing antioxidant power (FRAP), nitric oxide (NO) scavenging, lipid peroxidation (LPO) inhibition, iron chelation, and copper chelation assays, while neuroprotective potential was evaluated through inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The nanoparticles demonstrated concentration-dependent activity across all assays. The strongest antioxidant responses were recorded for ABTS (IC₅₀ = 210.21 µg/mL), DPPH (IC₅₀ = 290.96 µg/mL), and copper chelation (IC₅₀ = 168.76 µg/mL), while FRAP analysis revealed a dose-dependent increase in reducing power (absorbance =0.6099 ± 0.005 at 100 µg/mL). Enzyme inhibition assays showed notable AChE inhibitory activity(IC₅₀ = 245.70 µg/mL) compared to BChE (IC₅₀ = 1160.85 µg/mL). All activities were significantly lower than reference standards, indicating moderate but measurable bioactivity attributable to the phytochemical composition of A. indica extract and the nanoscale properties of the particles.
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Copyright (c) 2026 Oyesolape Basirat Akinsipo, Francis Olumide Oladapo, Adetoro Ajibike Osanyibi, Fatimoh Titilope Arole, Oluwaseun Adenike Orugun
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