Abstract:
The search for safer and environmentally friendly nanoparticle-synthesis methods is becoming more
prominent in sustainable nanotechnology. In this study, phytochemical-assisted green synthesis of
silver nanoparticles (AgNPs) was achieved using Eucalyptus globulus leaf extract (ELE), a rich
source of phenolics, flavonoids, and tannins. The ELE concentrations ranging from 1–6% w/v
provided differential phytochemical availability, directly influencing nanoparticle nucleation, growth,
and stabilization. UV–Vis spectroscopy confirmed surface plasmon resonance bands at 420-422 nm
responsible for AgNPs. FTIR analysis confirmed the presence of O–H, C=O, and C=C functional
groups responsible for both reduction and capping of the AgNPs. TEM imaging demonstrated a
concentration-dependent decrease in particle agglomeration, with 6% w/v ELE producing
predominantly spherical nanoparticles averaging 12.90 nm. XRD analysis indicated crystalline facecentred cubic structures of AgNPs. Antibacterial assays showed significant inhibitory activity against
Staphylococcus aureus and Klebsiella pneumoniae, with MIC values surpassing those of Neomycin.
These findings established that phytochemical-assisted green synthesis of AgNPs has a promising
antimicrobial potential against the pneumonia-causing pathogens with controlled morphology and
bioactivity.
