Green and facile synthesis of silver nanoparticles (Ag NPs) using Rhamnus prinoides (Gesho) leaf extract for antibacterial, antioxidant and photocatalytic activities

Abstract

The current work describes a simple and environmentally friendly method of creating silver nanoparticles (AgNPs) by employing leaf extract from Rhamnus prinoides (Gesho) as a capping and reducing agent. This environmentally friendly process provides a sustainable substitute for biological synthesis method. By adjusting the AgNO₃ concentration, extract-to-silver nitrate ratio, pH, and incubation duration, the biosynthesis conditions were adjusted. UV-Vis spectroscopy (λ_max = 407 nm) verified the production of AgNPs, while FTIR analysis revealed the functional groups in charge of stabilization and reduction. SEM photos displayed a uniform spherical shape, TGA proved their thermal stability up to 680°C, and XRD examination showed a face-centered cubic crystalline structure with an average particle size of 9.45 nm. The synthesized AgNPs exhibited significant antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes, outperforming the plant extract alone. Additionally, the AgNPs demonstrated strong antioxidant potential in a DPPH assay, with an IC₅₀ value of 48.85 μg/mL and excellent photocatalytic degradation of malachite green dye (95 % efficiency under visible light for 100 min). These results suggest that AgNPs synthesized using Rhamnus prinoides leaf extract have potential applications in antibacterial, antioxidant, and photocatalytic activities, making them promising candidates for biomedical and environmental applications.