Synthesis, antimicrobial and antioxidant bioevaluation of silver nanoparticles using leaf extract of Sarcochlamys pulcherrima

Abstract

In the present study, aqueous leaf extract of an underutilized vegetable Sarcochlamys pulcherrima was used to establish a straightforward, economical, and environmentally benign method for the synthesis of silver nanoparticles (AgNPs) with potent antioxidant and antibacterial activity. The synthesized AgNPs were characterized by UV-Vis spectroscopy, FT-IR spectroscopy, X-Ray diffraction (XRD)- and transmission electron microscopy (TEM) analysis. In the UV-Vis spectrum, the AgNP samples exhibited characteristic surface plasmon resonance band within 405–432 nm. The average crystallite size of the AgNPs calculated from the XRD data was found to be within the range of 15.6–25.6 nm. TEM analyses showed that most of the synthesised nanoparticles were spherical having dimensions in the range of 6–61 nm. The AgNPs exhibited significant antioxidant activity in the DPPH radical scavenging assay with a maximum of 89.12% inhibitory potential for the sample SP-8 and showed efficient anti-microbial potential against pathogenic bacterium Bacillus subtilis and Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) value of the sample SP-1 was found to be 0.78 μg/mL against P. aeruginosa which is at per with the MIC value of the standard neomycin (0.78 μg/mL). The minimum bactericidal concentrations (MBC) of the as-synthesized AgNPs for the selected bacterial strains were determined at concentrations of 25.0 μg/mL (B. subtilis) and 1.56 μg/mL (P. aeruginosa). This study concludes that the leaf extracts of the edible plant S. pulcherrima can be successfully utilised for convenient synthesis of AgNPs with antioxidant and antimicrobial potential.