Green Synthesis, Characterization, and Antifungal Activity of Copper Oxide Nanoparticles Using Murraya koenigii Leaf Extract

The biosynthesis of nanoparticles has gained significant attention as a cost-effective and environmentally friendly alternative to conventional chemical and physical synthesis methods. In this study, copper oxide (CuO) nanoparticles were synthesized through a green synthesis approach using aqueous extract of Murraya koenigii (curry leaves powder) as a natural reducing and stabilizing agent. Copper sulfate pentahydrate (CuSO₄•5H₂O) was used as the metal precursor for the synthesis process. The bio-reduction reaction was initiated by mixing the plant extract with the copper sulfate solution under controlled heating and continuous stirring conditions. The formation of CuO nanoparticles was confirmed by a visible color change in the reaction mixture, indicating the reduction of copper ions and nanoparticle formation. The synthesized nanoparticles were characterized using ultraviolet–visible (UV–Vis) spectroscopy to investigate their optical and physicochemical properties, Fourier transform infrared spectroscopy (FTIR) to identify functional groups responsible for reduction and stabilization, and X-ray diffraction (XRD) analysis to determine the crystalline structure of the CuO nanoparticles. Furthermore, the antimicrobial potential of the biosynthesized CuO nanoparticles was evaluated against fungal cultures to assess their antifungal activity. The results demonstrate that Murraya koenigii extract can serve as an effective, eco-friendly, and sustainable bio-resource for the synthesis of CuO nanoparticles with potential applications in antimicrobial and biomedical fields.