Copper Oxide nanoparticles were synthesized from Copper Sulphate and Areca Catechu leaves by using green synthesis method. Utilizing X-ray diffraction, the crystalline characterizations of synthesized nanoparticles were investigated. The optical properties pertaining to bio inspired green copper oxide synthesized nanoparticles were examined, and the energy band gap was also estimated. Functional group of CuO nanoparticles were confirmed using FTIR analysis. By Scanning Electron Microscope (SEM), the structural form of copper oxide nanoparticles made by green synthesis was evaluated. Green synthesized CuO NPs have been shown to have antimicrobial activity against gram negative bacteria.