Characterization, antimicrobial and toxicological properties of silver nanoparticles synthesized from Ocimum gratissimum leaves

Abstract

Ocimum gratissimum leaves were used in the synthesis of silver nanoparticles (AgNps) that were non-toxic and also possessed antimicrobial properties against clinically isolated pathogenic strains. Some bioactive agents in the aqueous extract of Ocimum gratissimum leaves (AEOgL) were identified. AgNp synthesis was carried out by incubating the AEOgL and 1 mM AgNO3. The brownish colour obtained upon reduction of silver by the AEOgL was observed. The phytochemicals present are tannins, glycosides, sterols, phenols, alkaloid and terpenoids. There was the presence of a surface plasmon resonance from the UV-visible scan. The synthesized silver nanoparticles were characterized by UV-visible spectrophotometry, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy/Energy Dispersive Analysis (SEM/EDX) and X-ray diffraction analysis. The SEM/EDX analysis indicated that the morphology of the nanoparticles is of a uniform structure and the size of the AgNp was 20 nm. The AgNps showed excellent antimicrobial activity against clinically isolated multi-drug resistant human pathogens used such as Escherichia coli and Staphylococcus aureus. For most biomarkers in the blood biochemistry analysis, there was no significant difference (p<0.05) between the control and treated groups except for alkaline phosphatase. It can concluded from this study that AgNps synthesized from aqueous extract of Ocimum gratissimum had antimicrobial properties and is also non-toxic at the dosage used.