Optimization of Green synthesis of silver nanoparticles using an aqueous extract of Foeniculum vulgare Mill. Seeds and evaluation of its antioxidant activity

In this study, silver nanoparticles were synthesized using aqueous extracts from seeds of Foeniculm vulgare. The free radical scavenging activity and total phenolic content of the aqueous extracts were assayed by the DPPH and Folin Ciocalteu methods, respectively. In addition, silver nanoparticles were successfully prepared and characterized by UV-Vis spectroscopy, particle size analyzer, energy dispersive X-ray analysis (EDAX), Fourier transform-infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). Several parameters were varied in order to optimize synthesis of the silver nanoparticles, including pH, volume of extract, volume of silver ion solution and reaction time. The mean diameter of the silver particles was 40 nm. FT-IR revealed the presence of the same functional groups in synthesized nanoparticles as in the crude extract. Energy-dispersive X-ray spectroscopy (EDAX) showed the presence of elemental silver in the synthesized nanoparticles. TEM showed that major parts of nanoparticles have a spherical morphology, in which several nanoparticles were agglomerated. The silver nanoparticles also showed antioxidant activity. This fast and convenient method of synthesis can be used for the large-scale production of nanoparticles and can serve as an environmentally-friendly method with a variety of biotechnological, pharmaceutical and medical applications.