Green synthesis of silver nanoparticles using leaves extract of Ajuga iva: characterizations, toxicity and photocatalytic activities

Currently, there is great interest worldwide in the use of plant-mediated green technologies to minimize the harmful effects caused by known traditional methods in the manufacture of nanoparticles. Therefore, the objective of this study was to develop a facile, eco-friendly, and cost-effective green approach for the synthesis of silver nanoparticles (Ag-NPs) using Ajuga iva extract. The synthesized nanoparticles (NPs) were characterized firstly by a visual indicator, in which the color of mixture will change from pale yellow to dark brown under optimal synthesis conditions. After that, the characterization was continued by ultraviolet-visible (UV-Vis) spectroscopy and scanning electron microscopy coupled with energy-dispersive spectrometry (SEM-EDX). The obtained results reveal that Ag-NPs were polygonal, with sizes ranging from 100 to 300 nm. Their characteristic peak absorbance was situated around 450 nm. The EDX analysis reveals a high percentage of silver atoms, which confirms the synthesis of silver NPs. Moreover, the FTIR study revealed that the Ag-NPs were capped by biomolecules. The in vitro toxicity activity, evaluated on model immune cells, showed an absence of any significant toxicity at the concentrations used since they did not affect either the cell viability of splenocytes and thymocytes, and the biological activity of B-lymphocytes. In addition, the photocatalytic activity of these biosynthesized NPs was studied against methylene blue, under solar irradiation where they showed an efficiency of 48.6% after 90 min of exposure. All those results make Ag-NPs synthesized by Ajuga iva a promising candidate for various biological and industrial applications.