Synthesis of Silver Nanoparticles from Cymbopogon flexuosus Leaves Extract and Their Antibacterial Properties

Here we report synthesis of silver nanoparticles using leaf extracts of four varieties of lemongrass (Cymbopogon flexuosus) namely krishna, neema, pragati and suvarna and their antibacterial activities against drug resistant bacteria Staphylococcus aureus, Pseudomonas aeruginosa and Acinatobacter bamunnii. Silver nanoparticles were synthesized by the bio-reduction of silver nitrate solution (1 mM) using water extracts of lemongrass leaves. Synthesis of silver nanoparticles was confirmed by the presence of an absorbance peak at 430-450 nm in UV-visible spectrum. Thus synthesized silver nanoparticles were analyzed by Dynamic Light Scattering (DLS) technique which revealed their z-average (nm) size 40-100 nm. The silver nanoparticles were tested for their antibacterial potential against drug resistant bacteria by agar well diffusion method. The results revealed that all the silver nanoparticles (4 mg/ml) tested exhibited strong antibacterial activities against S. aureus and P. aeruginosa with zone of inhibition ranged from 24-27 and 17-23 mm, respectively while less effective against A. bamunnii with zone of inhibition ranged 13-14 mm. In conclusion, lemongrass leaf extract can be used to synthesize silver nanoparticles of potential antibacterial activities against drug resistant bacteria.