Azadirachta indica -Mediated Synthesis of Iron Oxide Nanozymes with Superior Peroxidase-Like Catalytic Efficiency

Zahid H Shar; Muqadus Abbasi; Nusrat N Memon; Anoosha Maryam; Pawan Kumar; Pirah Ismail; Pirah Zahir

doi:10.61919/fh1edm46

Authors

Zahid H Shar Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Muqadus Abbasi Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Nusrat N Memon Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Anoosha Maryam Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Pawan Kumar Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Pirah Ismail Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author
Pirah Zahir Dr M.A Kazi institute of Chemistry, University of Sindh Jamshoro, Pakistan Author

DOI:

https://doi.org/10.61919/fh1edm46

Keywords:

Green synthesis; Azadirachta indica; iron oxide nanozymes; peroxidase-like activity; OPD oxidation; catalytic efficiency

Abstract

Background: Metal-based nanomaterials with natural enzyme-like activity, nanozymes are gaining popularity as alternatives to biological enzymes due to their superior stability and cost-effectiveness. The catalytic efficacy of iron oxide nanozymes may be diminished by aggregation during chemical production. Objective: This study aimed to synthesize iron oxide nanozymes using Azadirachta indica leaf extract and compare their structural composition and OPD–H₂O₂ peroxidase-like catalytic activity with chemically synthesized nanozymes. Methods: Iron oxide nanozymes were synthesized using chemical co-precipitation and Azadirachta indica-mediated green synthesis. The synthesized materials were characterized by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Peroxidase-like activity was evaluated using oxidation of o-phenylenediamine (OPD) in the presence of hydrogen peroxide(H₂O₂). Kinetic parameters were estimated using Michaelis–Menten analysis. Results: Green-synthesized nanozymes showed comparatively reduced aggregation and lower residual chlorine signal than chemically synthesized nanozymes. Azadirachta indica-mediated nanozymes generated the maximum absorbance at 451 nm in the OPD–H₂O₂ assay, suggesting more peroxidase-like activity. Kinetic analysis revealed that green-synthesized nanozymes had a higher Vmax and a roughly 5.4-fold higher Vmax/Km-based catalytic effectiveness than chemically synthesized nanozymes. Conclusion: Iron oxide nanozymes with enhanced catalytic performance were generated by Azadirachta indica-mediated synthesis, most likely as a result of phytochemical-assisted stabilization and surface modification. Before biosensing or environmental usage, additional phase characterization, replicate-based validation, and application-specific testing are needed

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