Green Fabrication of Copper Oxide Nanoparticles from Zingiber officinale as a Reducing and Stabilizing Agent for Antibacterial Effectiveness

Abstract

Aims: This study aimed to fabricate copper oxide nanoparticles (CuO NPs) using aqueous ginger (Zingiber officinale) rhizome extract as a reducing and stabilising agent and to evaluate their antibacterial activity against selected clinical bacterial isolates. Methodology: The fabricated CuO NPs were characterised by ultraviolet–visible (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and atomic force microscopy (AFM). Antibacterial activity was assessed by agar well diffusion, while minimum inhibitory concentrations (MICs) were determined using a resazurin-based broth microdilution assay. Results: A colour change from green to light yellow indicated CuO NP formation. UV–vis spectroscopy showed a distinct absorption peak at 290 nm. FTIR analysis identified absorption bands associated with functional groups including hydroxyl, amine, alkane, alkene, and ether groups. AFM showed an average particle diameter of 49.92 nm. At 1000 mg/mL, inhibition zones of 9, 15, 17, 13, and 11 mm were observed against Staphylococcus aureus, Aerococcus viridans, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa, respectively. MIC values were 62.5 mg/mL for A. viridans, E. coli, and P. aeruginosa and 125 mg/mL for S. aureus and K. pneumoniae. Conclusion: Ginger-mediated green fabrication produced CuO NPs with measurable antibacterial activity against both Gram-positive and Gram-negative isolates. The findings support further investigation of these green-fabricated nanoparticles as potential antibacterial materials.