Green synthesis of nanoparticles using Calendula officinalis extract from silver sulfate and their antibacterial effects on Pectobacterium caratovorum

Abstract

Abstract Pectobacterium caratovorum subsp. cacatovorum (Pcc) is one of the most important plant pathogens that cause a wide range of symptoms, such as soft rot in a wide range of plants. So in this work to control these pathogens, silver nanoparticles (NPs) were prepared by marigold flower extract using silver sulfate salt, for the first time. There are several ways to produce silver NPs; but, the use of plants in the synthesis of NPs has received much attention in recent years due to low cost, high production speed, efficiency, and environmental compatibility. The prepared silver NPs were characterized by UV–visible (UV–vis) spectroscopy, Fourier transforms infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS). Field Emission Scanning Electron Microscopy (FESEM) was used to determine the morphology and size of the NPs. Also, their antibacterial effect was evaluated by three methods of determining the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) and biofilm inhibition against Pcc. The present study showed that the green method produced uniform silver NPs with small size and antibacterial properties. It also showed that silver NPs synthesized due to the different chemical structure of silver sulfate salt have a weaker antibacterial effect than similar NPs synthesized from other silver salts. The MIC and MBC records were 40 and 160\xa0ppm, respectively. The NPs showed a bimodal effect on biofilm formation as the lowest biofilm formation achieved in 2.5 and 40\xa0ppm, respectively.