Molecular Networking‐Driven Chemical Profiling, Characterization, and Antibacterial Effects of Cuo Nanoparticles Synthesized from Citrus Unshiu Peel Extract

Molecular networking has emerged as a new in silico tool for analyzing liquid chromatography-mass spectrometry (LC-MS) data for better annotation and elucidation of novel compounds and different pathways. Green synthesized nanoparticles (NPs) have gained considerable attention as a result of their effectiveness in possessing good antimicrobial activity. Their eco-friendly nature and cost-effective synthesis have positioned them as sustainable nanomaterials in various fields. However, not much is known about the mechanism underlying the green synthesis of NPs. Therefore, herein, the copper oxide NPs (CuO NPs) are fabricated, and ultrahigh performance liquid chromatography-quadrupole time of flight mass spectrometry based molecular networking is utilized to understand the phytochemical relationship between the crude extract and the NPs, outlining metabolites that might be involved in reduction. Moreover, CuO NPs synthesized from Citrus unshiu fruit peels are tested for their antimicrobial and cytotoxic activities. Various characterization methods, such as X-ray diffraction, UV-vis spectroscopy, scanning electron microscopy-energy dispersive X-ray analysis, Fourier transform infrared, dynamic light scattering, and transmission electron microscopy, are employed to provide comprehensive insights into the atomic and structural characteristics of NPs. Molecular network reveals the presence of different metabolites such as isosakuranetin-7-O-rutinoside, hesperidin, skullcapflavone II, homoorientin, eupatorin-5-methylether, scoparin, and vitexin, which are recognized as antimicrobial and reducing agents. Additionally, the synthesized CuO NPs show exceptional antibacterial efficacy with a low minimum inhibitory concentration on Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Salmonella typhimurium, highlighting the potential of using LC-MS to explain the antimicrobial properties and green synthesis pathway.