R ubus ellipticus fruits extract-mediated cuprous oxide nanoparticles: in vitro antioxidant, antimicrobial, and toxicity study

The aim of the present study was to synthesize biologically active cuprous oxide nanoparticles (Cu2O-NPs) using green nanotechnology from aqueous extract of Rubus ellipticus fruits. The structural characterization of aqueous extract-mediated cuprous oxide nanoparticles (Ru-Cu2O-NPs) was performed using X-ray powder diffraction (XRD), Transmission electron microscope (TEM), Field emission scanning electron microscope (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and UV–Vis spectroscopy. Using standard techniques, Ru-Cu2O-NPs were also evaluated for their biological activities (antioxidant, antimicrobial, and anticancer) and toxicity. The XRD patterns and Rietveld refinement confirmed the phase purity of Ru-Cu2O-NPs with an average crystallite size of 25 nm. The FE-SEM and TEM images showed the formation of octahedron cages with a grain size of 0.82 ± 0.04 μm on average. The XPS analysis confirmed the presence of Cu1+ ions with many chemisorbed species on the surface. The determination of functional groups was carried out using FTIR with Cu–O stretching vibration at 635 cm−1. Tauc’s plot determined that the optical bandgap of the synthesized Ru-Cu2O-NPs was 1.28 eV. Compared to aqueous fruit extract, Ru-Cu2O-NPs showed significantly lower antioxidant activity. Furthermore, they showed higher antimicrobial activity (MIC) against Bacillus subtilis and Rosellinia necatrix (7.81 µg/mL), Staphylococcus aureus (15.62 µg/mL), and Escherichia coli, Pseudomonas aeruginosa, and Fusarium oxysporum (31.2 µg/mL). The Ru-Cu2O-NPs showed no toxicity against BM MSCs and HC cells at 12.5 µg/mL concentration, whereas the Ru-Cu2O-NPs showed anticancer activity against colon cancer cell lines (SW480 and SW620) at 100 g/mL concentration. These results indicate that Ru-Cu2O-NPs have good antimicrobial and anticancer properties but have low toxicity thus making them suitable for use in pharmaceuticals and food industries.