Biological Synthesis of Cobalt Oxide Nanoparticles Using Ziziphus oenopolia Leaf Extract

In this article, cobalt oxide nanoparticles were synthesized from the leaf extract of Ziziphus oenopolia by using cobaltous chloride hexahydrate. The prepared samples were characterized and subjected to the antimicrobial activity of some pathogens. The first confirmation of the formation of the cobalt oxide nanoparticles resulted from the reaction mixture's color change from light brown to dark brown at room temperature. Further, UV-Visible spectrum analysis showed a strong absorption band at the visible region around 269 nm, confirming the formation of stable cobalt oxide nanoparticles. From the FT-IR spectrum, the peaks at 3626, 2978, 1689,1519,1396 and 578 cm-1 show the presence of OH stretching, C=O group, C=C stretching, C-C bonds and cobalt oxide nanoparticles. The X-ray diffraction showed their crystalline nature with a face-centered cubic structure; the surface morphology revealed an irregular shape. The antibacterial studies have been carried out against four bacterial strains such as Staphylococcus aureus, Streptococcus aureus, Escherichia coli and Klebisella pneumonia; E. coli showed the highest zone of inhibition. The antifungal studies were exhibited against Candida albicans, Candida vulgaris, Aspergillus flavus and Aspergillus niger; Aspergillus niger showed the highest zone of inhibition.