Biosynthesis of Co₃O₄ nanoparticles using Ephedra gerandiana and their antibacterial, antifungal, and antioxidant activities

Cobalt oxide nanoparticles (Co₃O₄ NPs) have attracted significant attention in nanotechnology due to their unique physicochemical properties and potential applications in electronics, environmental remediation, and biomedicine. In the present study, Co₃O₄ NPs were synthesized via a green and eco-friendly approach using an extract of Ephedra gerardiana , a medicinal plant rich in bioactive compounds. The synthesized nanoparticles were characterized using UV–Visible spectroscopy, Fourier Transform Infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analysis. UV–Visible spectroscopy revealed a characteristic absorption peak at 633 nm, confirming the formation of Co₃O₄ NPs. FT-IR analysis identified the characteristic Co–O vibrational bands, further verifying cobalt oxide formation. XRD results demonstrated the crystalline nature of the nanoparticles with an average crystallite size of 45.09 nm. The biological activities of the synthesized Co₃O₄ NPs were evaluated through antibacterial, antifungal, and antioxidant assays. Antibacterial studies showed effective inhibition against Escherichia coli and other tested bacterial strains, with inhibition zones ranging from 14.5 to 15 mm. Antifungal activity against Aspergillus niger exhibited inhibition zones of 10–14 mm, which were significantly greater than those produced by the plant extract alone. The antioxidant potential was assessed using the DPPH radical-scavenging assay, in which the nanoparticles exhibited a maximum scavenging efficiency of 83.57%, demonstrating a strong concentration-dependent antioxidant response. These findings indicate that green-synthesized Co₃O₄ NPs possess promising antimicrobial and antioxidant properties and highlight the potential of Ephedra gerardiana -mediated synthesis as a sustainable route for developing functional nanomaterials for biomedical and environmental applications.