Biosynthesis of silver nanoparticles using Endod (Phytolacca dodecandra) leaf extract and evaluation of their antibacterial activity

Abstract

Nowadays, the applications of metal nanoparticles are growing rapidly in different fields due to their unique properties such as size and shape. Among the different metal nanoparticles, silver nanoparticles (Ag NPs) have attracted considerable attention. In recent years, biosynthesis of Ag NPs has gained much interest from researchers. Ethiopian flora has a potential to provide cost-effective non-hazardous reducing and stabilizing compounds in preparing Ag NPs. In this study, leaf extracts of endod (Phytolacca dodecandra) were used as a reducing and stabilizing agent for the synthesis of Ag NPs because it is cost effective, eco-friendly and has medicinal property. During the synthesis of the nanoparticles, we used 8 % (w/v) of 25 mL P. dodecandra leaf extract and 5 mM of 50 mL silver nitrate solution. The synthesised Ag NPs were characterized by using UV–Vis absorption, FTIR and XRD spectroscopy. Antibacterial susceptibility of green-produced Ag nanoparticles was examined against Gram-positive and Gram-negative microorganisms. The UV-Visible spectrum of the colloidal solutions has a maximum absorbance observed at 424 nm. FTIR spectrum analysis revealed the presence of functional groups in the leaf extract which are responsible for the reduction of Ag⁺ to Ag^o.  XRD spectrum showed the crystallinity and face-centered cubic (FCC) structure of the synthesized Ag nanoparticles. The particle size of silver nanoparticles calculated using the Debye-Scherrer formula was found to be equal to 22 nm.  The antibacterial susceptibility test showed an inhibition zone of 22 mm against S. aureus and an inhibition zone of 21 mm against S. typhi.