Investigation of antibacterial, antioxidant, cytotoxicity and photocatalytic dye degradation activity of green synthesized copper oxide nanoparticles using Ceropegia debilis plant extract

Present study reveals the synthesis of copper oxide nanoparticles an eco-friendly method using the leaf extract of Ceropegia debilis. An initial phytochemical screening test was performed. UV–visible spectroscopic absorbance at 257 nm confirms the formation of CuO NPs with the band gap of 2.4 eV. The XRD study confirms the crystallinity, monoclinic structure with grain size of 29.9 nm by Debye Scherer equation. The surface morphological features were investigated by SEM and HRSEM, which reveal that NPs were found to be spherical in shape, homogeneously distributed and the average size found to be 42.9 nm. The XPS technique predicts the copper and oxygen elements presence and their oxidation states. Furthermore, agar well diffusion method was carried out to test the growth of inhibition against the bacterial species Escherichia coli and Staphylococcus aureus. The maximum region of inhibition was shown by Escherichia coli at 30 µg/mL. CuO NPs show more scavenging ability than the plant extract with IC₅₀ value of 0.87 ± 0.08. The MTT assay was carried to evaluate the metabolic activities of human breast cancer cell line MCF7 and lung cancer A549 cell line. The percentage of cell inhibition of CuO NPs against MCF7 cell line is 66.9% with IC₅₀ of 40.28 µg/mL, and percentage of cell inhibition against A549 cell line is 58.47% with IC₅₀ of 68.27 µg/mL. Results revealed that synthesized CuO NPs show potent cytotoxic effect towards MCF7 cell line. The green synthesized NPs exhibit excellent photocatalytic degradation efficiency towards methylene blue dye of 95.8% within 105 min. Hence, from the above results, CuO NPs can be considered as a promising material for removal of toxic dyes and also serve as a good antibacterial, antioxidant and cytotoxic agent in biological field.