Green synthesis of gold and silver nanoparticles using Zingiber officinal Root extract and evaluation of their antibacterial activity

Abstract

Nowadays bacterial resistance has become one of the major problems in the field of medicine. The bacteria cause contamination or death of the host cell with the mechanism of toxicity. In recent decades, the use of nanoparticles has become prevalence as an antibacterial agent. For example, silver and gold nanoparticles are widely used as antibacterial agents in various industries. The synthesis of these particles is done in both chemical and green methods. Green synthesis method, which is known as an environmentally friendly and inexpensive method, is used to extract plants, fungi, etc. to restore and stabilize synthesized nanoparticles. Methods: In this work, we synthesized gold and silver nanoparticles using the ginger plant, and were evaluated the formation of nanoparticles and their size using transmission electron microscope, UV/Vis spectroscopy, zeta size analyzer, and infrared Fourier transform spectroscopy. The fresh ginger plant was finely chopped and extracted using alcohol and filtered with Whatman filter. In order to prepare serial concentrations of synthesized nanoparticles, broth culture medium was prepared and also a half McFarland suspension of the bacterium was added into this culture medium. After incubation of the nanoparticles with bacterial suspension in the incubator, the solutions were placed on agar culture media to obtain the minimum inhibitory concentration for each of the nanoparticles. Result: The chemical synthesized silver nanoparticles showed an inhibitory effect on Staphylococcus aureus and Escherichia coli by chemical methods at a concentration of 6.932 and 13.864 μg/ml, respectively. However, silver nanoparticles synthesized with plant extract at concentrations of 1.733 and 0.43325 μg / ml, inhibited the growth of Staphylococcus and Escherichia coli, respectively. In the case of chemical and green gold nanoparticles, Escherichia coli showed a high resistance to this nanoparticle, but in both syntheses, an inhibitory effect was observed on Staphylococcus aureus at a concentration of 17.952 μg/ml. Conclusion: The data obtained from the spectra, images, and information on the Gas Chromatography on the extract of ginger showed that the extract was properly reduced the nanoparticles and using the results obtained from bacterial tests, it can be concluded that the more antibacterial effect associated with the green synthesized nanoparticles could be due to the synergistic effect of the extract.