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11th Edition of World Nanotechnology Conference

March 23-25, 2026

March 23 -25, 2026 | Singapore
World Nano 2026

Mechanistic insight and in-vitro validation of phytochemical-functionalized ZnO nanoparticles as antioxidant and antimicrobial therapeutics against antimicrobial-resistant E. coli

Callistus Izunna Iheme, Speaker at Nanomaterials Conference
Federal University of Technology Owerri, Nigeria
Title : Mechanistic insight and in-vitro validation of phytochemical-functionalized ZnO nanoparticles as antioxidant and antimicrobial therapeutics against antimicrobial-resistant E. coli

Abstract:

Antimicrobial resistance (AMR) poses a significant threat to the global health sector. Zinc oxide nanoparticles (ZnO NPs) were synthesized with aqueous crude extract of Azadirachta indica, and the phytochemical compositions determined using Gas chromatography coupled to mass spectroscopy (GC-MS). They were further characterized using advanced spectroscopes and microscopes. The results showed arrays of ZnO NPs nanorods with maximal absorption wavelengths of 320 nm. The GC-MS revealed the presence of twenty volatile phytochemicals associated with the synthesized ZnO NPs. Among the volatile compounds, in silico study revealed Scoparone as the most bioactive compound. The ZnO NPs were separately functionalized with Scoparone-rich portion of the extract (ZnO NPs-S), and Ampicillin (ZnO NPs-amp). Subsequently, the nanoparticles were assessed for their antioxidants, and in vitro antimicrobial properties on antimicrobial-resistant Escherichia coli. In vitro study assessed the colony counts (cfu) of the E. coli in the presence of the antimicrobials; dehydrogenase inhibitory properties of ZnO NPs-S, ZnONPs-amp, extract of A. indica, and Ampicillin (standard drug). At the concentration of 500 μm/mL, 57.89% and 89.74% of the enzyme activities were inhibited by ZnO NPs-S, and ZnONPs-amp respectively. In silico study revealed Scoparone component of ZnO NPs-S as the most viable competitor of nicotinamide adenine dinucleotide (NAD+) for E. coli malate and histidinol dehydrogenases binding pockets. Antioxidant analysis revealed that ZnO NPs exhibited poor antioxidant potential. Conclusively, ZnO NPs-S exhibited good antimicrobial properties against antimicrobial-resistant E. coli, and was enhanced through conjugation with Ampicillin.  The application of the nanoparticles could ameliorate the increasing threat posed by AMR to the global health sector. Further toxicological, pharmacokinetic, and pharmacodynamic studies are encouraged on the nanoparticles.

Biography:

Dr. CI Iheme is a dedicated Toxicologist with over 11 years of experience in biochemistry, toxicology, and bioinformatics. A talented Lecturer offering expertise in building future experts in nanomedical studies with thought-provoking instruction. Seeks to expand student knowledge through lectures, group projects, and lively discussions. Always at the forefront of his field through the personal ethos of continuous professional development. A member of several professional associations, including the Nigeria Society for Biochemistry and Molecular Biology (NSBMB), the Society for Forensic and Analytical Science of Nigeria (SFASN), and others. Research interests border nanoscience for solutions to health problems. Several of his research articles are published in peer-reviewed journals.

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