Green synthesis of Ag-nanoparticles by roots-extract of Rumex nepalensis and their biological potentials

Abstract

The current study has reported the silver-nanoparticle’s green synthesis of silver-nanoparticles using silver ions from silver nitrate and by aqueous-root-extract of R. nepalensis. Initial clue of Ag-nanoparticles (AgNPs) formation was change in the color of solution from light brown to grey followed by broad band of UV-Visible spectrum obtained at 447 nm. Average size of the resulting AgNPs was 17.15 nm and X-Ray Diffraction (XRD) confirmed their crystalline cubic structure. SEM showed high intensity, spherical and cubic shaped AgNPs in addition to some irregular morphologyof AgNPs’ FT-IR analysis indicated incidenceof natural products which reducedthe silver and stabilized the resulting NPs and that is also evident by the rich phenolic (149 mg RE/g) and flavonoids (143mg GAE/g) contents in methanolic rootextract of R. nepalensis. These phenolic and flavonoid contents were also found responsible for antioxidant potency (IC50= 1.533) shown by the same extract. Antibacterial screening of methanolic extract, aqueous extract and biosynthesized AgNPs of R. nepalensis showed inhibition zone (8.0, 6.0 and 8.0mm) and (10.0, 11.0 and 8.0mm)against Escherichia coli and Pseudomonas aeruginosa, respectively. In this study, antibacterial activities of aqueous rootextract of R. nepalensis was found to be the most potent against Pseudomonas aeruginosa.