Investigation of Antibacterial Activity of Green Synthesized Zinc Oxide Using the Flower Extract of Plumeria Rubra.
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Abstract
Green-synthesized zinc oxide (ZnO) metal oxide nanoparticles (MNPs) have attracted considerable attention in advanced research fields owing to their unique properties and wide-ranging applications in biosensors, cosmetics, drug delivery, and antibacterial formulations [1, 2]. With the rising threat of microbial contamination and multidrug-resistant pathogens, which are now recognized as major global health concerns and leading causes of mortality, the exploration of effective antimicrobial agents has become crucial. In this context, we report a facile single-pot green synthesis of ZnO nanoparticles (KG-ZnO) employing aqueous flower extract of Plumeria rubra (locally known as Kathgolap) as a reducing, capping, and stabilizing agent, along with an evaluation of their antibacterial activity against four distinct bacterial strains. The aqueous extract of Plumeria rubra flowers was utilized as a reducing and capping agent for the eco-friendly synthesis of KG-ZnO MNPs. The optical properties, structure and morphology of the as-synthesized KG-ZnO metal oxide nanoparticles have been characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) supported with energy dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The disc diffusion method on Mueller-Hinton agar was employed to test the antimicrobial efficacy of KG-ZnO MNPs. Inhibition zones were measured after a 24-hour incubation at 37°C. X-ray diffraction (XRD) analysis using Rietveld refinement confirmed the hexagonal wurtzite phase with crystallite sizes of 51 nm for KG-ZnO. UV–visible spectroscopy showed band gaps of 2.98 eV. The green-synthesized KG-ZnO displayed significant antibacterial activity against both Gram-positive and Gram-negative bacteria. For E. coli, inhibition zones were 11.5 mm and 12.5 mm, for P. aeruginosa, inhibition zones were 8.5 mm and 10 mm, for S. flexneri, the inhibition zones were 9.0 mm and 10.5 mm, and finally, for S. aureus, the zones were 9.0 mm and 10.0 mm, for KG-ZnO NPs at 200 μg/disk and 400 μg/disk, respectively. Hence, the green-synthesized KG-ZnO nanoparticles have the potential to be used as a bactericidal component.
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Publication Details
- Type of Publication:
- Conference Name: 1st International Conference on Science and Humanities for Sustainable Development
- Date of Conference: 23/10/2025 - 23/10/2025
- Venue: Dhaka University of Engineering & Technology, Gazipur
- Organizer: Faculty of Science, DUET, Gazipur