biosynthesis of silver nanoparticles using root extract of the medicinal plant justicia adhatoda: characterization, electrochemical behavior and applications

a facile and green approach has been developed to synthesize silver nanoparticle (ag-nps). this was carried out by a biosynthetic route using justicia adhatoda root extract as reducing and stabilizing agent. the structure, composition, average particle size (~25 nm) and surface morphology of ag-nps were characterized by the x-ray diffraction, transmission electron microscope and atomic force microscope analyses. the possible functional groups in the plant extracts were identified by ft-ir analysis. electrochemical property of the ag-nps was analysed by cyclic voltammetry that displayed an oxidation peak potential at epa = 0.438 v. mechanism of the formation of ag-nps was proposed which showed that the phenolic compounds of the root extract respond for the reduction of silver ions to silver nanoparticles. ag-nps exhibit good antioxidant and antibacterial activities. this biosynthetic approach could open a path for environmentally friendly, simple, cost effective, alternate for conventional synthesis. this prevented hazardous chemicals and was useful for applications in medicine and large scale production of metallic nanoparticles.