Environmentally benevolent synthesis and characterization of silver nanoparticles using <i>Olea ferruginea</i> Royle for antibacterial and antioxidant activities
Abid Hussain, Ansar Mehmood, Ghulam Murtaza, Khawaja Shafique Ahmad, Aneela Ulfat, Muhammad Faraz Khan, Tariq Saif Ullah
Abstract
Abstract In this study, we reported an easy, rapid, cost-effective and environmentally benign method for the fabrication of silver nanoparticles (Ag-NPs) using Olea ferruginea as reducing, capping and stabilizing agent. For this, an aqueous extract of leaf and bark of O. ferruginea was treated with 1 mM AgNO 3 , which reduces Ag ions to Ag-NPs by establishing reddish brown color. The synthesized Ag-NPs were spherical crystals, with a mean size of 23 and 17 nm for leaf- and bark-mediated Ag-NPs, respectively. Fourier transform infrared spectroscopy affirmed the role of leaf and bark extracts of O. ferruginea as reducing, capping and stabilizing agent. These biosynthesized Ag-NPs showed profound antibacterial activity against Gram-negative ( Pseudomonas aeruginosa and Escherichia coli ) and Gram-positive ( Streptococcus pneumonia and Staphylococcus aureus ) bacteria. The highest antibacterial activity was shown by bark Ag-NPs against S. aureus (14.00 mm), while leaf Ag-NPs showed higher activity against S. pneumonia (13.00 mm). Additionally, they produced effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) as compared to plant extracts and positive control. It was observed that the bark-mediated Ag-NPs had higher percentage (90%) of scavenging potential than the leaf-mediated Ag-NPs (78%). The significance of the current study is the synthesis of eco-friendly, easy and cost-effective Ag-NPs as biomedical products.