Eco-Friendly Synthesis of Copper Oxide Nanoparticles via Pistachio Seed Coat Extract for Antimicrobial, Antioxidant, and Catalytic Applications

This study investigates the biogenic synthesis of copper oxide nanoparticles (CuO NPs) using the aqueous extract of pistachio seed coat as a stabilizing and reducing agent, and a better alternative to the traditional physicochemical approach. The CuO NPs were synthesized by a sustainable approach and characterized using XRD, UV–visible, FTIR, FESEM-EDX, and HRTEM-SAED, and are emphasized for their significance in comprehending how morphology, size, and surface chemistry affect the performance of CuO NPs. The UV–visible spectrophotometry showed an absorption at 273 nm, demonstrating the formation of CuO NPs. SEM and TEM provided a spherical shape with a size range of 50–100 nm. CuO NPs’ antifungal activity was examined against the fungal strains A. niger and P. chrysogenum, and their antibacterial efficacy was evaluated using the agar well disc diffusion method against E. coli and S. aureus. Staphylococcus aureus had the largest inhibitory zone, measuring 18 mm at 100 µg/mL, while Aspergillus niger had the smallest, measuring 8 mm at 25 mg. The IC₅₀ value of the sample was 319.55 ± 3.21 µg/mL. The IC₅₀ value indicates that the CuO NPs exhibit moderate antioxidant potential. The synthesized CuO NPs exhibited excellent catalytic efficiency in the cyclization reaction of chalcones. The findings of the present study highlight CuO NPs synthesis by an eco-friendly, cost-effective and sustainable method from pistachio shell extract. The synthesized CuO NPs demonstrated notable biological and catalytic activity that underscores their future need in various fields such as pharmaceutical, biomedical and industrial catalysis.