Green synthesis of silver nanoparticles using aqueous extract of dried Juglans regia green husk and examination of its biological properties

Abstract

Silver nanoparticles (AgNPs) have widespread applications. Recently, the synthesis of NPs using plant extract has attracted much attention. In this study, with an easy and rapid process at room temperature, AgNPs were produced by the aqueous extract of dried Juglans regia green husk, which is considered as a waste. The first sign of AgNPs synthesis was the color change of the sample from light green to yellowish brown. In addition, the production of AgNPs was examined by UV-Vis spectroscopy, dynamic light scattering (DLS), energy dispersive X-ray (EDX), Fourier transform infrared (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis. The antibacterial effect of AgNP on Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus and anticoagulation activity were determined. Synthesized silver colloid had electromagnetic absorbance at approximately 450 nm. The hydrodynamic diameter of monodisperse AgNPs was approximately 67 nm. The face center cubic metallic silver, which was spherical in shape, was in the range 3–50 nm with the average size of 7 nm. The extract showed antioxidant activity against 1,1-diphenyl-2-picryl hydrazyl (DPPH). Phenolic compounds, tannins, flavonoids, reducing sugars, proteins, ascorbic acid and carotenoids existing in the extract acted as reducing agents. AgNPs may be capped by biomolecules having O-H, C=O, N-H and other stabilizing functional groups.

Keywords

• antibacterial activity
• anticoagulation activity
• antioxidant activity
• juglans regia
• silver nanoparticles