Antimicrobial Activity of ZnO Nanoparticles Prepared Using a Green Synthesis Approach

Zinc oxide nanoparticles (ZnO NPs) were synthesized from cinnamon and bay leaves using chemical and environment-friendly synthesis approaches. The biosynthesized NPs were characterized using X-ray diffraction (XRD), which confirmed their crystalline nature. The morphology of the NPs was analyzed using scanning electron microscopy. The XRD analysis data showed average grain sizes of 9.968, 18.547, and 29.983 nm for the ZnO NPs. Energy-dispersive X-ray spectrum and XRD patterns showed that the synthesized ZnO NPs were unadulterated. These ZnO NPs were then used as antibacterial agents against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae). The antifungal activity of the biosynthesized NPs was also tested against common unicellular fungi (Candida albicans). The results showed that ZnO NPs extracted from cinnamon demonstrated a higher antibacterial activity compared with those of the NPs extracted from bay leaves or the chemically prepared ones.