In the present study, commercially available six plants leave extracts such as Eucalyptus camaldulensis, Azadirachta indica, Murraya koenigii, Avicennia marina, Rosa rubiginosa and Datura stramonium were utilized for the production of copper nanoparticles (CuNPs). The characterization of particles was performed by UV/Vis, TEM, SEM, EDX and FTIR spectroscopy. TEM images showed the creation of CuNPs having mean size ranged from 48 to 29 nm corresponding to different plant extracts. SEM analysis showed the formation of spherical form of NPs. FTIR spectroscopy verified the availability of phytochemical components as they serves the reducing, covering and stabilizing assistant of the CuNPs. Antimicrobial ability of NPs was performed against various clinical pathogenic strains by Oxford cup method. The synthesized NPs indicated potent antibacterial activity, with relatively low values of MIC between 15 and 60 μg/mL. The antibacterial effect of each CuNPs was observed in the resulting order A. indica > D. stramonium > M. koenigii > R. rubiginosa > A. marina > E. camaldulensis. After 12 h exposure with A. indica synthesized CuNPs, the SEM images of S. typhi showed destruction of cell membrane and cell lysis was clearly observed after interaction with lipopolysaccharide. In conclusion, these obtained CuNPs could be precisely applied in treatment protocols without any covering or core-shell procedures.

Keywords: Antibacterial activity; Copper nanoparticles; Green synthesis; Pathogenic bacteria; Polysaccharides interactions.