Phytochemical-Mediated ZnO Nanoparticles from Chromolaena odorata: Structural Characterisation and Antimicrobial Efficacy against Multidrug-Resistant Clinical Isolates, Nigeria
Hannah Ndidiamaka Okorie
Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, Agbani 402004, Nigeria.
Chigozie Peace Okorie
Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Medicine University of Nigeria, Enugu Campus, Enugu 400001, Nigeria.
Goodnews Onyedikachi Ikeh *
Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, Agbani 402004, Nigeria.
Angel Chihurumnanya Leonard
Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, Agbani 402004, Nigeria.
Nwoke Obinna Chidubem
Department of Pharmacology and Therapeutics, Faculty of Basic Clinical Sciences, College of Medicine, University of Nigeria.
Igwe Chidiebere Collins
Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Enugu State University of Science and Technology, Agbani 402004, Nigeria.
Anthony A. Attama
Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka 410001, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Nanoparticles (NPs), ranging from 1–100 nm, exhibit unique properties due to their compact atomic arrangement, enhancing mechanical, electrical, magnetic, optical, catalytic, and antibacterial characteristics compared to macroscopic materials. The rising threat of multidrug-resistant pathogens necessitates novel antimicrobial agents. This study explores the green synthesis of zinc oxide nanoparticles (ZnO NPs) using Chromolaena odorata leaf extract with zinc acetate dihydrate (Sample A), zinc sulphate (Sample S), and zinc nitrate (Sample N) as precursors. The NPs were characterised using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) analysis, and ultraviolet-visible (UV-Vis) spectroscopy. XRD revealed wurtzite ZnO structures with crystallite sizes of 9.1–9.2 nm (A), 3.2–15.9 nm (S), and 7.5–38 nm (N). SEM showed spherical (A), irregular (S), and rod-like (N) morphologies, while EDX confirmed Zn and O as primary elements with trace phytochemical-derived elements. FTIR identified phenolic and flavonoid capping, and BET indicated high surface areas (235.505–325.475 m²/g). UV-Vis spectra displayed absorption peaks at 374–383 nm, consistent with ZnO’s bandgap. Antimicrobial assays demonstrated significant activity against multidrug-resistant clinical isolates from Enugu State University Teaching Hospital, Nigeria, including bacteria and Candida albicans, with Sample S’s high surface area correlating with enhanced efficacy. These findings highlight the role of precursor chemistry in tailoring NP properties and underscore the potential of Chromolaena odorata-mediated ZnO NPs as effective antimicrobial agents. The NPs’ biocompatibility and high surface area suggest further applications in wound healing and photocatalysis, warranting future in vivo and mechanistic studies.
Keywords: Antimicrobial activity, BET analysis, Chromolaena odorata, EDX spectroscopy, FTIR spectroscopy, green synthesis