Green synthesis of copper oxide nanoparticles using Juglans regia leaf extract and assessment of their physico-chemical and biological properties

Copper oxide nanoparticles (CuO NPs) were green synthesized using walnut leaf extract. Effects of three synthesis parameters namely; amount copper salt (1-4 g), amount of walnut leaf extract (10-40 mL) and furnace temperature (300-500°C), on the particle size as manifested in broad absorption peak (λ max , nm), concentration (absorbance), antioxidant activity and antibacterial activity as minimum inhibitory concentration (MIC) of the fabricated CuO NPs were studied using response surface methodology, based on Box behnken experimental design. The spherical and crystalline monodispersed fabricated CuO NPs with mean particle size of 80 nm, were achieved using optimum synthesis parameters including 1 g copper salt, 14 mL walnut leaf extract and 490°C of furnace temperature. The fabricated CuO NPs at these conditions had maximum antioxidant activity of 83.64% and minimum MIC value of 1.78% w/v against E. coli , with λ max and absorbance values of 226 nm, 4.44% a.u., respectively.