Development and characterization of biogenic copper oxide nanoparticles, with an exploration of their antibacterial and antioxidant potential

This study outlines the synthesis of biogenic copper oxide nanoparticles (CuONPs) using an extract derived from Cassia fistula Linn (Cf) leaves through a green synthesis approach. Characterization of the synthesized CfBio-CuONPs was carried out using UV- VIS, FTIR, DLS, XRD, and TEM studies. The CfBio-CuONPs exhibited a prominent peak at 272 nm in UV-VIS spectroscopy, and XRD measurements confirmed their crystalline nature. The FTIR spectrum of CfBio-CuONPs revealed the presence of functional groups such as O-H and aromatic groups. TEM analysis confirmed that the CfBio-CuONPs were predominantly spherical with diameters ranging from 15 to 25 nm. Subsequently, the antibacterial potential of CfBio-CuONPs was evaluated against four pathogenic bacteria, including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Bacillus subtilis. Among these, B. subtilis exhibited the highest zone of inhibition (26.93 +/- 2.01 mm), followed by E. coli (24.25 +/- 1.04 mm), P. aeruginosa (23.98 +/- 0.97 mm), and S. epidermidis (22.97 +/- 1.20 mm). CfBio-CuONPs demonstrated maximum antioxidant activity (78 +/- 1.54%) at a dose-dependent concentration of 2000 mu g/ml. Furthermore, in vitro toxicity assessment using the toxtrak test indicated that CfBio-CuONPs exhibited a significantly stronger toxic effect value/PI against E. coli (93.52%) compared to P. aeruginosa (92.65%), B. subtilis (91.25%), and S. epidermidis (82.89%). These results underscore the notable toxicity of CfBio-CuONPs against E. coli, surpassing that against other bacteria and conventional antibiotics. This study highlights the potential utility of CfBio-CuONPs for eradicating pathogenic microorganisms and suggests potential implications for ecotoxicology.