Green Synthesis, Characterization, Antioxidant, Antibacterial and Antibiofilm Activity of Piper betle-mediated Silver Nanoparticles Against Foodborne Pathogens

Abstract

The present study aimed to synthesize silver nanoparticles (AgNPs) using Piper betle leaf extract through a green and eco-friendly approach and to evaluate their antioxidant, antibacterial, and antibiofilm activities against selected foodborne pathogens. Piper betle-mediated silver nanoparticles (PB-AgNPs) were synthesized using an aqueous leaf extract as a natural reducing and stabilizing agent. The formation of PB-AgNPs was confirmed by a visible color change and further characterized using UV–visible spectroscopy, dynamic light scattering (DLS), zeta potential analysis, and scanning electron microscopy (SEM). The synthesized PB-AgNPs exhibited a characteristic surface plasmon resonance peak at 459 nm, with nanoscale particle size and moderate colloidal stability. The SEM analysis revealed predominantly spherical nanoparticles with an aggregated morphology. The antioxidant activity of PB-AgNPs was evaluated using the DPPH assay, which demonstrated a concentration-dependent free radical scavenging activity with an IC_₅₀ value of approximately 170 μg/mL. The antibacterial activity assessed using the agar well diffusion assay showed significant inhibition against Escherichia coli MTCC 41 and Staphylococcus aureus ATCC 13565. Furthermore, the PB-AgNPs exhibited strong concentration-dependent antibiofilm activity, as evidenced by the crystal violet staining assay. The findings of the present study suggest that PB-AgNPs possess promising antioxidant, antibacterial, and antibiofilm properties and may serve as potential alternative antimicrobial agents for food safety and biomedical applications.