Biosynthesis and antimicrobial studies of zinc oxide nanoparticles of Vernonia amygdalina Leaf with varying concentration of zinc oxide

Abstract

The extract of some plants and their zinc oxide nanoparticles (ZnO-NPs) are observed to be less active on some clinical pathogen, despite the numerous achievement on nanoparticles of plants in the field of medicine.The research reports the effect of varying the concentration of ZnO on the bioactivity of ZnO-NPsof Vernonia amygdalin. Different zinc oxide concentrations (0.2 M, 0.6 M, and 1.0 M) and a constant volume of V.amygdalina leaf were used to synthesize the ZnO-NPs. The ZnO-NPs were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet (UV) spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Based on the EDX analysis, it was deduced that the ZnO-NP is rather pure, with oxygen concentrations of 50.2 % and zinc concentrations of 49.8 %. The SEM investigation confirmed that the ZnO-NPs had a spherical or elliptical shape, and the XRD results showed that the nanoparticles were made of hexagonal wurtzite. The scanning electron microscopy data show that ZnO-NP are spheres, and the UV–Vis spectrometer found an absorption peak at 345 nm. The FTIR analysis confirmed that the stretching vibration frequency of 611.93 cm−1 was due to ZnO. The bioactive potential of ZnO-NP in V. amygdalina leaves was estimated using clinical pathogens such as Proteus mirabilis, Pseudomonas aureginosa, Bacillus cereus, Bacillus subtilis, and Salmonella typhi. At 25 mg/L, V. amygdalina was equally effective as gentamycin against clinical pathogens, with an inhibition zone ranging from 10.40 ± 0.163–11.60 ± 0.82.However, the ZnO-NP with a high concentration of ZnO (0.6 M and 1.0 M) has an inhibition zone above that of gentamycin at 10 mg/L. It therefore implies that the biosynthesis of ZnO-NP from V. amygdalina with high concentrations of ZnO increases the sensitivity of clinical pathogens.