Document Type : Original Article
Authors
1
Department of Chemistry, Faculty of Science, El-Menoufia University, Shebin El -Kom, Egypt
2
DepDepartment of Chemistry, Faculty of Science, El-Menoufia University, Shebin El -Kom, Egyptartment of Chemistry, Faculty of Science, Menoufia University
3
Department of Pathology, Faculty of Medicine, El-Menoufia University, Shebin El-Kom, Egypt
4
Department of Chemistry, Faculty of Science, Tobruk University, Libya
Abstract
The escalating prevalence of multidrug resistance (MDR) worldwide has spurred a critical imperative
to explore and innovate novel therapeutic modalities and potent antimicrobial agents. Amide Schiffbase
ligands (referred to as H3L1 and H3L2) have emerged as promising candidates for combating a
spectrum of pathogens including Gram-negative bacteria, Gram-positive bacteria, and certain
antifungal strains, amid the scarcity of novel antibiotics. Concurrently, β-naphthylamide (PAβN), a
peptidomimetic compound, has garnered attention as an efflux pump inhibitor (EPI) aimed at
surmounting efflux-mediated multidrug resistance. In this investigation, the antibacterial efficacy of
two Schiff base ligands synthesized through the condensation of (N-(2-amino phenyl)-2-
hydroxybenzamide) with hydroxybenzaldehyde, and (N-(2-aminoethyl)-2-hydroxybenzamide) with
hydroxybenzaldehyde, alongside their respective complexes [H3L1.Cu(OAc)2].2H2O,
[H3L1CuCl2].2H2O, [H3L1Ag2(SO4)], [H3L1Hg(SO4)(H2O)]·2H2O, [H3L2Cu(OAc)2]·2H2O, and
[H3L2CuCl2]·3H2O). The ligands and their complexes were characterized using elemental and
spectroscopic techniques such as IR, UV-VIS, Mass Spectra, 1H-NMR and ESR measurements as well
as Magnetism, Conductivity, Thermal Analyses (DTA and TGA) and Electronic microscope. The
conductivity measurements confirmed non electrolytic in nature, however, The electron microscope
data indicate that, the complexes were found in nano-form. ESR spectra for Cu(II) complexes showed
axial type with d(x2-y2) ground state. The compounds were assessed individually against a spectrum of
bacteria including Escherichia coli (ATCC:10536), Klebsiella pneumoniae (ATCC:10031),
Staphylococcus aureus (ATCC:13565), Streptococcus mutans (ATCC:25175), and Candida albicans
(ATCC:10231), encompassing antibiotic-susceptible strains. Preliminary results of minimum inhibition
concentration (MIC) assays revealed notable antimicrobial activity exhibited by the complexes
[H3L1.Cu(OAc)2].2H2O, [H3L1CuCl2].2H2O, [H3L1Ag2(SO4)], [H3L1Hg(SO4)(H2O)]·2H2O,
[H3L2Cu(OAc)2]·2H2O, and [H3L2CuCl2]·3H2O) when compared to the ligands in isolation. Further
analysis via fractional inhibitory concentration (FIC) indices demonstrated enhanced MIC values
indicative of additive and synergistic effects upon combining Nano metal amide Schiff base complexes
with H3L1 and H3L2. These findings underscore the therapeutic promise inherent in the combined
utilization of these metal complexes.
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