An investigation of the antimicrobial and antioxidant efficacy of copper oxide (I) nanoparticles: A green approach from Myrica esculenta fruit extract

Abstract

The current research emphasized the creation of copper oxide nanoparticles (Cu2O NPs) employing aqueous and methanol fruit extracts of Myrica esculenta, which were applied as a capping and reducing agent. Advanced characterization techniques like XRD, FTIR, FESEM, TEM, Raman, and UV–Vis spectroscopy were applied to ascertain the structure and characteristics of the Cu2O NPs. The results revealed the synthesis of uniformly spherical Cu2O NPs in both aqueous and methanol extracts, with the latter showing particles embedded in a sheet-like structure. The mean crystallite sizes were determined to be 25.45 and 22.04 nm for Cu2O NPs derived from the aqueous and methanol extracts. Furthermore, the antioxidant potential of the extracts and as-prepared Cu2O NPs was assessed using a DPPH assay. At the same time, their antimicrobial activity was accessed through the disc diffusion technique (for bacteria), poisoned food method (for fungi), and minimum inhibitory concentration assay. The results revealed that Cu2O NPs derived from the methanol extract exhibited significant antioxidant potential (IC50 of 57.38 µg/mL) compared to those derived from the aqueous extract (IC50 of 71.60 µg/mL). The methanol extract-based Cu2O NPs displayed higher antimicrobial efficacy against Bacillus subtilis (15.62 µg/mL) and Staphylococcus aureus (31.25 µg/mL). In contrast, aqueous extract-based Cu2O NPs exhibited similar and higher activity against B. subtilis (31.25 µg/mL). Additionally, Cu2O NPs of methanol extract showed higher antifungal potential than aqueous extract-mediated NPs. These findings highlight the immense potential of these bio-inspired NPs for various biomedical applications, owing to their exceptional biological properties.