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. 2022 Feb 3;7(6):4970-4990.
doi: 10.1021/acsomega.1c05801. eCollection 2022 Feb 15.

In Vitro Antimicrobial Evaluation, Single-Point Resistance Study, and Radiosterilization of Novel Pyrazole Incorporating Thiazol-4-one/Thiophene Derivatives as Dual DNA Gyrase and DHFR Inhibitors against MDR Pathogens

Affiliations

In Vitro Antimicrobial Evaluation, Single-Point Resistance Study, and Radiosterilization of Novel Pyrazole Incorporating Thiazol-4-one/Thiophene Derivatives as Dual DNA Gyrase and DHFR Inhibitors against MDR Pathogens

Hazem Ali Mohamed et al. ACS Omega. .

Abstract

A series of thiazol-4-one/thiophene-bearing pyrazole derivatives as pharmacologically attractive cores were initially synthesized using a hybridization approach. All structures were confirmed using spectra analysis techniques (IR, 1H NMR, and 13C NMR). In vitro antimicrobial activities, including the minimum inhibitory concentration (MIC), minimum bactericidal/fungicidal concentration (MBC/MFC), and time-kill assay, were evaluated for the most active derivatives 4a, 5a, 7b, 10, and 13. These derivatives were significantly active against the tested pathogens, with compound 7b as the most active derivative (MIC values range from 0.22 to 0.25 μg/mL). In the MBC and MFC, the active target pyrazole derivatives showed -cidal activities toward the pathogenic isolates. Further, the inhibition of biofilm formation of Staphylococcus aureus and Staphylococcus epidermidis was also carried out. Additionally, these derivatives displayed significant antibiofilm potential with a superior % reduction in the biofilm formation compared with Ciprofloxacin. The target derivatives behaved synergistically with Ciprofloxacin and Ketoconazole, reducing their MICs. Hemolytic results revealed that these derivatives were nontoxic with a significantly low hemolytic activity (%lysis range from 3.23 to 15.22%) compared with Triton X-100 and showed noncytotoxicity activity with IC50 values > 60 μM. In addition, these derivatives proved to be active DNA gyrase and DHFR inhibitors with IC50 ranging between 12.27-31.64 and 0.52-2.67 μM, respectively. Furthermore, compound 7b showed bactericidal activity at different concentrations in the time-kill assay. Moreover, a gamma radiation dose of 10.0 kGy was efficient for sterilizing compound 7b and enhancing its antimicrobial activity. Finally, molecular docking simulation of the most promising derivatives exhibited good binding energy with different interactions.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Structures of the antibiotics containing pyrazole or thiazole/tetrahydrothiazole moieties as bioactive cores and our designed derivatives.
Scheme 1
Scheme 1. Synthesis of Pyrazole Derivatives Containing Thiazol-4-one Moieties
Scheme 2
Scheme 2. Synthesis of Thiazolin-4-one and 4-Aminothiophene-3-carboxylate Derivatives Containing Pyrazole Moieties
Scheme 3
Scheme 3. Suggested Mechanism with the Intermediates (A, B, and C) for the Synthesis of 4-Amino-thiophene-3-carboxylate Derivatives Containing Pyrazole Moieties 7a and 7b
Scheme 4
Scheme 4. Synthesis of 4-Oxothiazoles and Thiazolo[3,2-a]pyridine Derivatives Having a Pyrazole Scaffold
Figure 2
Figure 2
Reduction % of biofilm-forming S. aureus and S. epidermidis by the potent compounds 4a, 5a, 7b, 10, and 13 compared with Ciprofloxacin.
Figure 3
Figure 3
In vitro time-kill evaluation of (a) 7b and (b) CIP against clinical bacterial isolates at 2 × MIC.
Figure 4
Figure 4
In vitro time-kill evaluation of (a) 7b and (b) KCA against clinical Candida isolates at 2 × MIC.
Figure 5
Figure 5
(a) 2D and 3D binding mode of compound 7b inside the active site of DNA gyrase (2XCT). (b) 2D and 3D binding mode of compound 5b inside the active site of DNA gyrase (2XCT).
Figure 6
Figure 6
2D and 3D binding mode of compound 4a inside the active site of DHFR (1DLS)
Figure 7
Figure 7
(a) 2D and 3D binding mode of compound 10 inside the active site of DHFR (1DLS). (b) 2D and 3D binding mode of compound 7b inside the active site of DHFR (1DLS).

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