Green Synthesis of Zinc Oxide Nanoparticle Using Justicia procumbense Leaf Extract and Their Application as an Antimicrobial Agent

Abstract

Justicia procumbense leaf, stem and root samples were investigated by phytochemical analysis. Leaf and stem showed higher bioactive compounds compared to the root part. The current work comprises, the zinc oxide nanoparticles (ZnO NPs) synthesis using aqueous leaf extract of J. procumbense and to assess its effect on antimicrobial activity. Formed ZnO NPs were characterized by UV-vis, FT-IR, XRD, and SEM analysis. The UV-vis spectrum exhibited the absorption peak at 370 nm. The FT-IR results indicated leaf extract active biomolecules responsible for the formation ZnO NPs and it confirms band at 421 cm-1 corresponding to a weak Zn-O stretching. XRD result revealed the hexagonal wurtzite structure with the space group P63mc. The SEM image expresses spherical morphology with a range between 5 to 15 nm. Different concentration of synthesized ZnO NPs was tested against different bacterial (Escherichia coli, Staphylococcus aureus, and Pseudomonas auriginosa) and fungal (Aspergillus niger, A. fumigatous and A. flavus) strains by disk diffusion method. 10 mg concentration of ZnO NPs showed the best antimicrobial effect on all tested bacterial and fungal strains. The potential antimicrobial agents of ZnO NPs can be used for biomedical and pharmaceutical applications. Whereas, the plant leaf extract can be used for other nanoparticles synthesis.