Green Synthesis and Antimicrobial Activity of Spondias mombin-Derived Iron and Copper Nanoparticles Against Staphylococcus aureus and Aspergillus niger

Abstract

This study examines the antimicrobial capabilities of iron and copper nanoparticles synthesized using 
Spondias mombin leaf extract against clinical isolates of Aspergillus niger and Staphylococcus aureus. The 
iron nanoparticles (Sm-FeNPs) and copper nanoparticles (Sm-CuNPs) were synthesized using a green 
approach and then characterized using techniques such as UV-Vis spectroscopy, X-Ray Diffraction 
Analysis (XRD), Scanning Electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), 
and Particle Size Analysis (PSA). The nanoparticles were then tested at different (5–30 mg/mL) 
concentrations using the agar well diffusion method. By measuring the size of the clear zones surrounding 
the wells, the antimicrobial activity was ascertained. This was followed by the determination of the 
minimum inhibitory concentration (MIC), which aids in determining the lowest concentration at which 
microbial growth can be inhibited. From the results obtained, Sm-CuNPs exhibited quantitatively stronger 
antimicrobial effects than Sm-FeNPs, producing inhibition zones ranging from 6.5–14.0 mm for 
Staphylococcus aureus and 5.25–12.0 mm for Aspergillus niger, compared to 6.0–11.0 mm and 4.0–9.0 mm 
respectively for Sm-FeNPs. Sm-CuNPs achieved a MIC of 10 mg/mL for both organisms, whereas Sm
FeNPs achieved a MIC of 10 mg/mL for Staphylococcus aureus and 20 mg/mL for Aspergillus niger. These 
findings show that Sm-CuNPs were more effective against the two tested microbes. This is attributed to 
their ability to damage cell membranes and generate reactive oxygen species (ROS) that harm microbial 
cells. Since Sm-CuNPs showed significant activity against both bacterial and fungal isolates, it suggests 
their potential usefulness in treating infections caused by Staphylococcus aureus and Aspergillus niger. 
Moreover, the study highlights the ecological benefit of using Spondias mombin leaf extract for 
nanoparticle synthesis, supporting the growing interest in eco-friendly nanotechnology for antimicrobial 
applications.