Biogenic Synthesis of Copper Oxide Nanoparticles Using Falcaria vulgaris L. Leaf Extract and Assessment of Its Antibacterial Activity against Salmonella Paratyphi-A

The copper oxide nanoparticle has attracted increasing attention among all metal oxides due to its distinctive properties and applications. Chemical and physical methods of synthesizing copper oxide nanoparticles are challenged by high reagent costs, equipment limitations, and environmental hazards. Following green chemistry principles, copper oxide nanoparticles were synthesized using Falcaria vulgaris leaf extract as a bio-reducing agent and copper nitrate as a source of copper in this study. As a result, copper oxide nanoparticles can be produced without the use of organic chemicals, and this method is non-toxic, economically viable, easily scaled up, and takes less time to produce. The formation of copper oxide nanoparticles was confirmed by the dominant surface plasmon resonance (SPR) peak at 350 nm. Based on scanning electron microscope (SEM) images, the particles were spherical and morphologically sized between 58–200 nm. Energy dispersive X-ray spectroscopy (EDX) analysis confirmed the presence of Cu and O in the pyhto-synthesized nanoparticles. Fourier transform infrared (FTIR) spectroscopy as well showed a distinct peak of Cu–O stretching vibration positioned at 609.36 cm^–1. The structural characterization was performed utilizing X-ray diffraction (XRD) in line with reflections of the face-centered cubic (fcc) phase of the copper oxide nanoparticles. The average particle size of nanoparticles was found to be 82.9 nm by using XRD analysis and Scherrer equation. In addition, since Salmonella Paratyphi-A is less studied than many other bacteria, we examined the antibacterial properties of copper oxide nanoparticles, against this relatively resistant bacterium. By checking the inhibition zone and minimum concentration of phyto-synthesized nanoparticles, it was determined that they effectively inhibited bacteria growth.