Antioxidant and antibacterial activities of biosynthesized silver nanoparticles using aqueous Terminalia catappa leaf extracts as novel reducing agent

Abstract

In this study, silver nanoparticles (AgNPs) were successfully synthesized from aqueous Terminalia catappa leaf extract that acts as a novel reducing agent. Various parameters, including pH, temperature and reaction time, were determined. The UV-visible spectra showed the main peak at 416 nm, which was the characteristic surface plasmon resonance of AgNPs. The spherical shape and particle size of 49 ± 0.01 nm were observed from SEM, TEM and laser particle size analysis (LPSA). FTIR spectra of the leaf extract exhibited the characteristic functional groups that should be responsible for Ag+ ion reduction. The EDX spectrum proved that the obtained sample is silver. The antioxidant activity of AgNPs treated with the leaf extract as determined by the DPPH assay was higher compared to that of Terminalia catappa leaf extract, and the treated AgNP sample exhibited high antibacterial potential against both Gram-positive and Gram-negative bacteria.