Fatemeh Nakhjiri - Department of Biology, Payame Noor University, Iran
Mahboubeh Mirhosseini - Department of Biology, Payame Noor University, Iran
Malihe Alsadat Mozaheb - Technical and Vocational University of HazratRoghayeh, Yazd, Iran

Objective(s): Silver nanoparticles (Ag NPs) are not only specific physical and chemical properties but also are considered for their antibacterial activity and ecofriendly.Materials and Methods:In this study a simple, cost effective biologically method for Ag+reducing to Ag NPs using Echinops extractas a stabilizer, and reducing agent.Ag NPs were analyzed using UV-Vis spectrometry,TEM, XRD and FTIR. The role of Echinops concentration, silver nitrate concentration, pHand reaction time on the synthesis of nanoparticles were studied. Antibacterial activity of the Ag NPs werecarried out by disc diffusion method against Staphylococcus aureus and Escherichia coli. Alsothe amount of MBC and MIC for AgNPs against bacteria wereinvestigated.Results: The AgNPs formation were observed as a color change of the mixture from colorless to dark-brownish. The UV-Vis spectroscopy absorbance peak at 420 nm confirmed the presence of Ag NPs. TEM analysis, showed Ag NPs were spherical, triangle and bar particles in shape with size range within 1.32-36.41 nm. XRD study showed particles were crystalline in nature. FTIR analysis detected that Ag NPsare functionalized with biomolecules that are present in the aqueous Echinops extractact as the reducing agents and stabilizing the nanoparticles. The results showed that the time of reaction, temperature, pH, Echinops extract concentration and AgNO3concentration could accelerate the formation of AgNPs.Conclusion: In this study, synthesized Ag NPs havethe efficient antibacterial activity against pathogenic bacteria. Ag NPs havean importantfunction in the field of nanotechnology and nanomedicine.

Antibacterial activity, Echinops extract, Green synthesis, Silver nanoparticle