The green synthesis, characterization and evaluation of the biological activities of silver nanoparticles synthesized from Iresine herbstii leaf aqueous extracts

Silver has been used since time immemorial in different chemical form to treat burns, wounds and several infections caused by pathogenic bacteria. Advancement of biological process of nanoparticles synthesis is evolving into a key area of nanotechnology. The current study deals with the synthesis. characterization of silver nanoparticles using Iresine herbstii and evaluation of their antibacterial, antioxidant and cytotoxic activity. The reaction mixture turned to brownish gray color after 7 days of incubation and exhibits an absorbance peak around 460 nm characteristic of Ag nanoparticle. Scanning electron microscopy (SEM) and EDX analysis showed silver nanoparticles were pure and polydispersed and the size were ranging from 44 to 64 nm. X-ray diffraction (XRD) studies revealed that most of the nanoparticles were cubic and face centered cubic in shape. Fourier transform infrared spectroscopy (FTIR) showed nanoparticles were capped with plant compounds. Biosynthesized silver nanoparticles showed potent antibacterial activity against human pathogenic bacteria. Phytosynthesized nanoparticles exhibited strong antioxidant activity as well as cytotoxicity against HeLa cervical cell lines. The approach of green synthesis seems to be cost efficient, eco-friendly and easy alternative to conventional methods of silver nanoparticles synthesis. The powerful bioactivity demonstrated by the synthesized silver nanoparticles leads towards the clinical use as antibacterial, antioxidant as well as cytotoxic agent. (C) 2012 Elsevier B.V. All rights reserved.