Green synthesis and characterization of copper nanoparticles using Azadirachta indica (neem) leaf extract and evaluation of their antimicrobial activities
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Date
2025-06
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Abstract
The present study demonstrates the green synthesis of copper oxide nanoparticles (CuONPs) utilizing
aqueous extracts of Azadirachta indica (neem) leaves. Fresh neem leaves were processed to obtain the
extract, which served as a bioreducing and stabilizing agent for the synthesis of CuONPs via a simple
aqueous-phase method using copper nitrate. The formation of CuONPs was indicated by a colour
change from brown to sea green and confirmed through X-ray diffraction (XRD), scanning electron
microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) analyses. XRD results
revealed the monoclinic crystalline structure of CuO nanoparticles with an average crystallite size of
approximately 3.3 nm. SEM analysis showed irregular, aggregated morphologies, while FTIR spectra
identified functional groups responsible for the reduction and stabilization of nanoparticles.
Antibacterial activity assessed by the well diffusion method indicated that the biosynthesized CuONPs
exhibited substantial inhibitory effects against Pseudomonas aeruginosa and Klebsiella oxytoca,
but no activity against Staphylococcus aureus. The findings highlight the potential application of
neem-mediated CuONPs as eco-friendly antimicrobial agents, particularly targeting Gram-negative
bacterial strains.
Keywords: Green synthesis, Eco-friendly, CuONPs, Bacterial strains, Multidrug-resistance