Green Synthesis of Silver Nanoparticles Using Aqueous Extract of Rosmarinus Officinalis L.: Synthesis and Antibacterial Activities

A green approach by using aqueous extract of Rosmarinus officinalis L. for silver nanoparticles (AgNPs) synthesis was developed and optimized. Parameters affecting the synthesis of AgNPs, such as temperature, extract pH, silver nitrate and extract (ratio of plant mass to extraction solvent volume) concentrations were investigated and optimized. Optimum conditions for the synthesis of silver nanoparticles (AgNPs) are as follows: Ag concentration, 1 mM, extract concentration, 2 g/L, pH=9 and temperature, 45 °C. Biosynthesized silver nanoparticles were characterized using UV Visible absorption spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM). TEM and DLS analyses shown the synthesized AgNPs were predominantly spherical in shape with sizes in the range of 20-40 nm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNPs were determined for several pathogens include Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus cereus and Staphylococcus aureus. The antibacterial activity of the synthesized AgNPs was compared with several antibiotic drugs as control. This eco friendly and cost-effective synthesis method can be potentially use for large-scale production of silver nanoparticles.