Green Synthesis of Copper Oxide Nanoparticles Using Pulp and Peel Extracts of Cucurbita pepo Followed by Characterization and Comparative Antimicrobial Evaluation

Green synthesis of nanoparticles represents a promising eco-friendly approach, as it utilizes plant extracts as reducing and stabilizing agents without the need for hazardous chemical reagents. This study aims to evaluate the efficiency of green synthesis in producing copper oxide nanoparticles (CuONPs) using two plant-based extracts derived from pumpkin: pulp juice and peel extract. The synthesized samples were characterized using a range of physicochemical techniques, including Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The results confirmed the formation of pure, well-crystallized nanoparticles in the monoclinic phase, with both samples exhibiting similar particle sizes. However, distinct morphological differences were observed: the pulp-derived CuONPs showed a uniform spherical distribution, while the peel-derived ones displayed significant surface agglomeration. The biological activity of the nanoparticles was assessed against selected bacterial and fungal strains. The pulp-based CuONPs demonstrated selective antibacterial activity against Staphylococcus aureus , whereas the peel-based particles exhibited no antimicrobial effect. These findings highlight the critical role of surface properties in governing biological interactions. Overall, the results support the use of plant extracts as sustainable green agents for the synthesis of multifunctional nanoparticles. Emphasis should be placed on optimizing extract composition to tailor surface characteristics for targeted applications, particularly in photocatalysis and antimicrobial treatments.