Green Synthesis of Silver Nanoparticles from the Leaf Extract of Persea americana: Characterization and Antibacterial Activity Studies

Abstract

Silver nanoparticles (AgNPs) were synthesized using the leaf extract of Persea americana. Characterization of the particles was done by Uv-visible extinction spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD) studies. The particles are spherical to quasi-spherical and the diffraction pattern in the PXRD spectrum and the selected area x-ray diffraction (SAED) confirms the silver being crystallized in to face centred cubic (FCC) structure. The average particle size calculated through PXRD data is 23 nm.  Antibacterial activity of the synthesized AgNPs against the spreading of gram-negative bacteria, Escherichia coli (E. coli) and gram-positive bacteria, Staphylococcuus aureus (S. aureus) were determined and the results were compared with that exhibited by ciprofloxacin, a commercial reference substance. The minimum inhibitory concentrations (MIC) of the AgNPs in their solid solutions in nutrient agar media were found to be 1.00 ×10⁻⁴ g/mL against E – coli and 7.50 ×10⁻⁵ g/mL against S. aureous. The bactericidal efficacy exhibited against S. aureous bacterium, by AgNPs synthesized from Persea americana is superior compared to that exhibited by the reference compound selected for the study.