Biosynthesis of Gold Nanoparticles and Their Antimicrobial Activity and Cytotoxicity

nanoparticles are being extensively used in various biomedical applications due to their small size to volume ratio and extensive thermal stability. Present study reports a green chemistry approach for the biosynthesis of gold nanoparticles (AuNPs) by using the leaf extract of Saururus chinensis. The nanoparticles were characterized by UV-Vis spectroscopy, X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses. Elemental and vibrational analyses were done with Energy-Dispersive X-ray analysis (EDAX) and Fourier Transform Infrared Spectroscopy (FTIR) respectively. Bioreduction of gold ions by Saururus chinensis leaf extract resulted in the synthesis of cubic, truncated triangle and irregular structured nanoparticles. These AuNPs showed an absorption peak at 542 (immediately at 50 C) and 544 (after 24 hrs) nm in UV-Vis spectrum corresponding to the plasmon resonance of AuNPs. FTIR spectrum confirmed the involvement of alkenes groups in capping and reduction of AuNPs. Green synthesized AuNPs were found toxic against S. aureus (KCTC 1916), S. substilis (lab culture), E. coli (KCTC 2441), C. albicans (lab culture) and S. cerevisiae (KCCM 1020) both in liquid and solid group media. MTT assay showed 27.6% cell inhibition in lower concentration (0.2 mM) and > 90% cell inhibition after 24 hrs exposure at higher concentrations (0.8 to 1 mM). Extracellular synthesis of AuNPs using leaf extract is a simple, cheap and environmentally benign alternative to physical and chemical procedures.