Biosynthesized copper oxide nanoparticles by Psidium guajava plants with antibacterial, antidiabetic, antioxidant, and photocatalytic capacity

With an increasing focus on green technologies, this research aimed to synthesize copper oxide nanoparticles (CuO-NPs) using leaf extracts from Allahabad Safeda and Hisar Safeda for environmental and health protection. A range of concentrations of leaf extracts were employed in the synthesis of nanoparticles, utilizing 1–9% extract from Allahabad Safeda and 3–11% extract from Hisar Safeda. The synthesized CuO-NPs were characterized by UV–visible spectrophotometry, Dynamic light scattering, Fourier transform infrared spectroscopy, and Scanning electron microscope with energy-dispersive X-ray spectroscopy. CuO-NPs synthesized using 3% Allahabad Safeda extract and 5% Hisar Safeda extract exhibited a particle size of 15.88 nm and 14.05 nm, respectively. CuO-NPs synthesized with Allahabad Safeda extract exhibited superior antibacterial, antioxidant, antidiabetic, and photocatalytic properties. Their antibacterial tests demonstrated significant inhibition zones against Staphylococcus aureus (20.5 cm), Streptococcus latis (20.7 cm), Escherichia coli (19.5 cm), and Pseudomonas aeruginosa (19.7 mm). Additionally, CuO-NPs from Allahabad Safeda extract (70 µg/mL) exhibited 68.23% of scavenging activity against 2,2-diphenyl-1-picrylhydrazyl. Moreover, the same CuO-NPs at 100 µg/mL concentration showed 67.32% α-amylase inhibition and 75.18% α-glucosidase inhibition, confirming their antidiabetic activities. Furthermore, these nanoparticles demonstrated high performance in photocatalytic degradation, by degrading 82.31% methylene blue and 88.54% crystal violet within 150 min of UV irradiation. Overall, the findings highlight the feasibility of CuO-NPs synthesis using Allahabad Safeda extract and their potential applications in antibacterial treatment, combating diabetes, antioxidation, and environmentally friendly dye photodegradation process. Graphical Abstract: (Figure presented.).