Green Synthesis of Copper Oxide Nanoparticles (CuONPs) using Clematis simensis, Characterization and their Antibacterial Activity against MultiDrug Resistant Bacteria

Abstract

Recent advancements in material science and green nanotechnology have led to the development of bioinspired nanoparticles, which offer promising alternatives for combating multidrugresistant bacteria, a major public health concern. The unique, antibactericidal properties of CuONPs offer invaluable possibilities for combating multidrug-resistant bacterial infections. In the present study, copper oxide nanoparticles were synthesized by a cost-effective, eco-friendly, and single-step method using ethanolic leaf (ET) extract of clematis simensis (CS) acting as a reducing agent. CS-CuONPs and ethanolic leaf extract were characterized by UV-Vis, FT-IR, GC-MS, XRD, DLS, SEM, and TEM. UV-Vis spectrum showed a characteristic peak at 286 nm, indicates the formation of CS-CuONPs. Phytochemical, GC-MS, and FTIR analysis of ethanolic leaf extract of C. simensis revealed the presence of polyphenolic compounds, flavonoids, and their related bioactive compounds like Eugenol and methyl eugenol, with the broad peak 3599.77 cm-1 indicating the OH functional group responsible for reducing, capping, and stabilizing agents in the synthesis of CS-CuONPs. The XRD diffractogram proved the existence of a crystalline structure of CS-CuONPs with an average size of 22.7 nm, and the DLS analysis of CS-CuONPs was -28.3 mV, which confirms moderate stability and high surface negative charge. SEM and TEM analysis revealed that the CS-CuONPs were predominantly pseudo-spherical with some irregular shapes, and had an average particle size of 22.65 nm.The CS-CuONPs have shown strong antibacterial activities against the tested Gram-positive bacteria B. subtilis, with the highest zone of inhibition of 30±0.4 mm and minimum inhibitory concentration of 100µg/mL. In addition, E. faecalis and K. pneumoniae showed moderate susceptibility with the zone of inhibition of 20±0.2 mm for both bacteria in comparison with Positive controls (Ciprofloxacin). The results suggest that clematis simensis, with its rich phytochemical profile, enhances nanoparticle stability and antibacterial efficacy. Therefore, CSCuONPs show potential as an effective alternative for combating MDR bacteria.