Biosynthesis, characterization and antimicrobial activities of zinc oxide nanoparticles from leaf & seed extracts of Malva neglecta Wallr.

Abstract

Plant-based nanoparticles have a number of benefits over traditional physicochemical approaches, and they may be used in a variety of medical and biological applications. In recent study, a green synthesis approach for zinc oxide nanoparticles (ZnO NPs) using Malva neglecta Wallr. leaf (MWL) and seed (MWS) aqueous extracts were reported. MWL mediated ZnO NPs (MWL-ZnO-NPs) and MWS mediated ZnO NPs (MWS-ZnO-NPs) were synthesized using an environmentally friendly and simple technique with minimal reaction time and calcination temperature. The structural and chemical characterization of the biosynthesized ZnO NPs was performed using UV-Vis, FTIR, XRD, TGA, TEM, and EDX. Synthesized nanoparticles showed the UV–Visible spectroscopy absorption peak at 372 and 376 nm for MWL and MWS-ZnO-NPs, respectively, which confirm the synthesis of ZnO NPs. Furthermore, the FTIR spectrum indicated bioactive functional groups and metal-oxygen groups. The TEM analysis displayed that two different synthesized ZnO NPs, exhibited a somewhat spherical structure with an average particle size between 40 and 50 nm, regardless of the type of extract. EDX analysis approved the Zn and O in the synthesized ZnO NPs. The XRD results revealed that MWL-ZnO-NPs had a similar crystal structure to MWS-ZnO-NPs. The dose-dependent free radical scavenging capability of zinc oxide nanoparticles was determined using the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) test. Furthermore, the antibacterial activity of ZnO NPs was investigated using the paper disc diffusion technique against two clinical strains of Escherichia coli and Staphylococcus aureus using the zone of inhibition and minimum inhibitory concentration (MIC).