Green Synthesis of Silver Nanoparticles using Aqueous Extract of Prunus africana and their Antimicrobial Activities

The alarming effect of antibiotic resistance prompted the search for alternative medicine to resolve the microbial resistance conflict. Over the last two decades, scientists have become increasingly interested in metallic nanoparticles to discover their new dimensions. Prunus africana is a traditional medicinal plant rich in phytochemicals. In this study, we expand this knowledge by synthesizing anti-bacterial silver nanoparticles (AgNPs) using Prunus africana stem bark extract as a reducing, capping, and stabilizing agent. The biosynthesis of AgNPs was carried out using 0.1 M silver nitrate and 2% w/v stem bark extract. The effect of temperature, contact time, and concentrations on the synthesis of AgNPs was examined using UV-Vis spectra. The formation of AgNPs was indicated by the development of a dark-brown color from red-brown. Using a UV-Vis spectrophotometer, the surface plasmon resonance observed at 432.5 nm indicated the formation of silver nanoparticles. Probable vibrational stretches that are characteristic of silver nanoparticles, such as OH and C = O vibrations, were identified using an FT-IR spectrophotometer. The characteristic peaks of the XRD pattern confirmed the synthesis of pure AgNPs with an average crystalline size of 17.07 nm. The TEM (transmission electron microscopy) analysis confirmed that the synthesized AgNPs were spherical with sizes ranging from 15.95 nm to 43.04 nm. The DLS analysis confirmed the stability of AgNPs in solution at -12.44 mV. The synthesized silver nanoparticles (AgNPs) exhibited antibacterial activity against four bacterial strains ( Pseudomonas aeruginosa , Escherichia coli, Staphylococcus aureus , Bacillus subtilis ) and one fungus ( Candida albicans ).