ASSESSMENT OF ANTIMICROBIAL ACTIVITIES OF ZINC NANOPARTICLES SYNTHESIZED FROM AQUEOUS LEAF EXTRACTS OF OCIMUM GRATISSIMUM AND VERNONIA AMYGDALINA

Abstract

Synthesis of nanoscale metals has been reported for environmental pollution effects and health problems which have made green synthesis via plant extracts to be preferred. As a viable alternative, use of plant extracts for effective synthesis of nano metallic particles has therefore been deployed due to safety and simple methodology. This study explored the potential of Ocimum gratissimum and Vernonia amygdalina leaf extracts as reducing agents for the synthesis of zinc nanoparticles. The extracts were utilized to reduce Zn²⁺ ions, and the resulting nanoparticles were characterized using UV-vis spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The XRD analysis revealed average particle size of 20.78 nm for nanoparticles synthesized with Ocimum gratissimum and 19.56 nm for Vernonia amygdalina. The antimicrobial properties of the synthesized nanoparticles were evaluated against Bacillus thuringiensis (ATCC 789794.1), Staphyloccoccus aureus (ATCC 20923) and Escherichia coli (ATCC 25922). The results showed significant inhibition zones ranging from 8-19 mm for O. gratissimum and 6 – 18 mm for V. amygdalina-mediated nanoparticles. In comparison, doxycycline demonstrated 18-20 mm zones of inhibition, while deionized water showed no inhibitory effect. This study has demonstrated the effectiveness of the plants leaf extracts in synthesizing zinc nanoparticles with potent antimicrobial properties.