Green Synthesis of Silver Nanoparticles from Aqueous Extracts of Trachyspermum ammi L. Seed and Evaluation of the Antioxidant Activity of this Extract

Research into the preparation of nanomaterials has increased during the past few decades due to the unique industrial properties of these materials. The nanoparticles produced by chemical methods have generated concern due to the hazardous and toxic materials used to make them and possible environmental damage. Silver nanoparticles are of interest because of their biological and medical applications. However the toxic nature of some of the chemical methods to make nanomaterials are in contrast with principles of green chemistry. For this reason, a variety of biological systems have been used. In this study, aqueous extracts of Ajowan (Trachyspermum ammi L. ) were prepared and this extract was used to reduce silver (I) to silver nanoparticles. Ajowan, a herbaceous plant, belongs to the family Umbelliferae. The nanoparticles obtained by this method were characterized by transmission electron microscopy, infrared spectroscopy, ultraviolet-visible spectroscopy and particle size analysis, which showed an average diameter of 40 nm for synthetic nanoparticles. In addition, the antioxidant properties of the aqueous extract and a solution containing silver nanoparticles was measured using the DPPH technique. Finally, the total phenolic content of the extract was evaluated.