Phytosynthesis of stable silver nanoparticles using aqueous extract of Salviar hytidea Benth. and comparison of its antimicrobial Activities with natural plantextract

The present study is the first report on the phytosynthesis of silver nanoparticles from aqueous extract of Salvia rhytidea Benth and comparison of its antimicrobial Activities with natural plant extract. Plant samples were collected at the flowering stage in June 2017 from the heights of Taftan Mountain (length 60 degrees and 44 minutes east longitude and width 28 degrees and 33 minutes north and at an altitude of 1394 m above sea level). After preparation of extract by maceration method, the silver nanoparticles were biosynthesized. Then, parameters such as reaction pH, concentration of AgNO3 and reaction time were studied and optimized. After characterization of nanoparticles by transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques, their antimicrobial activity against Salmonella typhimurium, Escherichia coli, Bacillus cereus and Staphylococcus aureus, Aspergilus Flavus and Penicillium expansum were investigated and compared with aquatic extract by Disk diffusion method and MIC test. The results showed that silver nanoparticles had maximum absorption at 400- 415 nm, an average size of 20-25 nm and a spherical and uniform shape. Antimicrobial activity of showed that the antimicrobial effects were concentration-dependent and in equal concentrations, the nanoparticles had a higher inhibitory effect than aquetic extract, in which at 50µg/mL the highest inhibitory effect was observed against Staphylococcus aureus (19 mm) and Aspergillus flavus (19 mm). Based on the results, plants have a high potential for biosynthesis of nanoparticles that can be used as antiseptic in various industries.