Green Synthesis of Silver Nanostructures Using Aqueous Extract of Dracocephalum kotschyi and Evaluation of Antioxidant Properties of Herbal Extracts and Antibacterial Feature of Green- Synthesized Nanostructures

Abstract

Silver nanoparticles have a profound role in the field of high sensitivity biomolecular detection, catalysis, biosensors and medicine. In the present study, aqueous extract of Dracocephalum kotschyi has been used for the synthesis of silver nanoparticles. In this study, we evaluated the antioxidant features and the possibility of biosynthesis of AgNPs using an aqueous extract of Dracocephalum kotschyi and also evaluated the antibacterial activities of the synthesized nanoparticles. An eco-friendly and cost-effective protocol for the synthesis of Ag nanoparticles by utilizing a renewable natural resource, aqueous solution of Dracocephalum kotschyi, was proposed. Synthesized nanoparticles were characterized by UV–Vis spectroscopy, SEM, EDS, and XRD pattern. At first, the extract of Dracocephalum kotschyi was assessed to determine and confirm the presence of an antioxidant feature. Resuscitation of one mM silver nitrate solution was carried out by the herbal extract. The solution containing AgNPs obtained from green synthesis had a maximum optical density at 225 nm. In addition, the presence of AgNPs was approved by energy-dispersive X-ray spectroscopy (EDS). Images of the scanning electron microscope demonstrated that the synthesized AgNPs had the shape of rods and the size distribution of 48-51 nm. One of the benefits of this method is a uniform size distribution. Moreover, the effects of reaction time and concentration of the herbal extract were assessed by ultraviolet-visible (UV-Vis) spectroscopy. In the end, we assessed the antibacterial impact of the synthesized AgNPs against some pathogenic bacterial strains. According to the results, the produced nanostructures had a proper impact on two bacteria of Escherichia coli and Staphylococcus aureus. According to the results of the present study, Dracocephalum kotschyi can be a suitable compound for the synthesis of nanostructures due to its indigenous cultivation and great medicinal properties.