Rosmarinus officinalis leaf extract mediated green synthesis of silver nanoparticles and investigation of its antimicrobial properties

Green synthesis of metallic nanoparticles (NPs) has been reported using plant extracts, which has dual properties of stabilizing and emulsifying agents. Development of biologically inspired synthesis of nanoparticles has evolved as an important branch in nanotechnology. In this work, silver nanoparticles (Ag-NPs) were synthesized at room temperature using rosemary (Rosmarinus officinalis Linn.) leaf extract. Formation of green Ag-NPs was confirmed by some thoughtful techniques like as UV-visible, FTIR, SEM & TEM, and XRD. Polyphenols in R. officinalis leaf extract acts as reducing and stabilizing agents for the formation of size controlled Ag-NPs and after 30 min nucleation started to proceed. Surface plasmon resonance (SPR) confirmed the formation of Ag-NPs with maximum absorbance at lambda(max) of 450 nm. The Fourier transform infrared spectroscopy (FT-IR) spectra of leaf extract shows the presence of phenolic functional groups which reduces silver ion to Ag-NPs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show the spherical morphology of Ag-NPs with the size range of 10-33 nm. X-ray diffraction (XRD) spectra show four prominent peaks of the crystalline metallic Ag-NPs. At last antimicrobial activities of green NPs were examined and results showed that Green synthesized Ag-NPs had effective antibacterial and antifungal activities. By these deals, green synthesis of NPs as an eco-friendly and inexpensive method in large scale for medicinal and industrial application severely recommended. (C) 2015 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.