[en] A new approach to the synthesis of ZnO with a green method has been carried out using the cucurbitaceous aqueous extract in alkaline medium at room temperature. The plant extract is an alternative to toxic chemicals. The synthesised oxide was characterized by UV-visible spectrophotometry, x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and EDX for the structural, morphological and optical properties. Physico-chemical properties of catalyst were determined by the methods of Brunauer–Emmett–Teller surface area analysis (BET). The XRD, FTIR, SEM and EDX analyses confirmed the structure of isolated ZnO powder. Also, the antibacterial activity is assessed against standard strains of Gram-negative bacteria (Pseudomonas aeruginosa ATCC 9027), Gram-positive bacteria (Staphylococcus aureus ATCC 6538) using the Mueller-Hinton agar well diffusion. The adsorption potential of the synthesised compound against metribuzin was equally investigated. Batch adsorption tests were performed. The experimental adsorption equilibrium data were fitted to the Langmuir, Freundlich and Temkin models. The best fits were obtained for Langmuir isotherm. (paper)