Copper nanoparticles derived from the extract of Ononis natrix (L.): Characterization, antibacterial, and antibiofilm...

Nanoparticles have attracted considerable interest due to their expanding applications in biomedicine, including anticancer and antibacterial activities. This study investigated the synthesis of copper nanoparticles (CuNPs) using an ethanolic extract of Ononis natrix, followed by an assessment of their antibacterial and antibiofilm activities against marine bacteria. Ultraviolet-visible spectroscopy, scanning electron microscopy with energy dispersive X-ray analysis, and Fourier transform infrared spectroscopy were used to describe the CuNPs. They were then tested for their antibacterial and antibiofilm activities. The extract showed significant levels of polyphenols and flavonoids. The formation of CuNPs was confirmed by UV-visible spectroscopy, which displayed a characteristic peak at 408 nm. Fourier transform infrared spectroscopy analysis indicated the presence of bioactive compounds in the plant extract and the CuNPs. X-ray diffraction revealed the crystalline structure of the CuNPs with an average size of 27.6 nm. Cytotoxicity assays using brine shrimp nauplii indicated low toxicity of CuNPs, with an LC50 of 977.23 μg/mL. Significant antibacterial activity of CuNPs against resistant marine bacteria was observed, with MICs ranging between 0.078 to 0.0195 mg/mL. CuNPs exhibited significant anti-adhesion and anti-biofilm activities against tested bacteria, with a percentage of inhibition ranging from 49.48 ± 7.01% to 91.98 ± 6.10%. Scanning electron microscopy confirmed the inhibition of biofilm formation on surfaces treated with CuNPs, showing significant alterations in bacterial morphology. These results suggest multiple applications of CuNPs derived from Ononis natrix, particularly in developing antifouling agents. They underscore the potential of green synthesis of CuNPs with enhanced properties for various environmental applications, with lesser toxic potency.