Green biosynthesis of CuO & Ag–CuO nanoparticles from Malus domestica leaf extract and evaluation of antibacterial, antioxidant and DNA cleavage activities

The reactivity of metallic and bimetallic nanoparticles of copper and silver towards in vitro study has been quantitatively investigated. Here, we report an easy synthesis of nanoparticles by the green method using Malus domestica leaf extract, which acts as a good stabilizing agent. The synthesized CuO and Ag–CuO nanoparticles have shown Surface Plasmon Resonance maxima (SPR) at 335 and 440 nm, respectively. The particles are spherical and crystalline in nature with average sizes between 18 and 20 nm. The Malus domestica leaf-capped nanoparticles have exhibited interesting antibacterial activity with both Gram-positive and Gram-negative bacteria at microgram concentrations. The antioxidant activity of the synthesized nanoparticles has also been measured on the basis of the free radical scavenging activity by the DPPH (1,1-diphenyl 2-picrylhydrazyl) method. Moreover, the DNA cleavage activities of the synthesized nanoparticles have been screened by agarose gel electrophoresis using the E. coli pBR322 plasmid as a target. Hence. owing to the biologically active nature of the synthesized nanoparticles, these greenly synthesized NPs act as a potent therapeutic agent.