Vitex negundo and Euphorbia milii leaf extracts aided green synthesis of copper oxide nanostructures for effective inactivation of pathogenic bacteria

[Display omitted] •CuO nanostructures were green synthesized using Vitex negundo and Euphorbia milii leaf extracts.•Experiential reflections of CuO nanostructures could be well to pristine monoclinic unit cell structure.•EDS spectra depicted Cu and O elemental peaks presence with oxygen vacancies.•FESEM images disclosed hierarchical CuO nanoparticles/nanorods and sphere-like CuO nanoparticles formation.•CuO nanostructures disclosed higher antibacterial activity due to oxygen vacancy and more ROS generation. A facile and green route was followed to synthesize copper oxide (CuO) nanostructures using Vitex negundo and Euphorbia milii leaf extracts. Structural, elemental, chemical, spectral, and morphological features of CuO nanostructures were determined by XRD, EDS, FTIR spectroscopy, UV–Vis spectrophotometer and FESEM, respectively. The CuO nanostructures disclosed considerably higher antibacterial activity against selected Gram-positive and Gram-negative pathogenic bacteria over commercial antibiotic (Vancomycin). This enhanced activity could be accredited to the generation of more ROS associated with oxygen vacancy and the size of CuO nanostructures. Particularly, hierarchical CuO nanoparticles/nanorods prepared using V. negundo leaf extract exhibited the highest antibacterial activity due to their lower size range.