Development and radiosterilization of new hydrazono-quinoline hybrids as DNA gyrase and topoisomerase IV inhibitors: Antimicrobial and hemolytic activities against uropathogenic isolates with molecular docking study.

This study aimed to synthesize new potent quinoline derivatives based on hydrazone moieties and evaluate their antimicrobial activity. The newly synthesized hydrazono-quinoline derivatives 2, 5a, 9, and 10b showed the highest antimicrobial activity with MIC values ≤1.0 µg/ml against bacteria and ≤8.0 µg/ml against the fungi. Further, these derivatives exhibited bactericidal and fungicidal effects with MBC/MIC and MFC/MIC ratio ≤4. Surprisingly, the most active compounds displayed good inhibition to biofilm formation with MBEC values ranging between (40.0 ± 10.0 - 230.0 ± 31.0) and (67.0 ± 24.0 - 347.0 ± 15.0) µg/ml against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. The hemolytic assays confirmed that the hydrazono-quinoline derivatives are non-toxic with low % lysis values ranging from 4.62% to 14.4% at a 1.0 mg/ml concentration. Besides, compound 5a exhibited the lowest hemolytic activity value of ~4.62%. Furthermore, the study suggests that the hydrazono-quinoline analogs exert their antibacterial activity as dual inhibitors for DNA gyrase and DNA topoisomerase IV enzymes with IC50 values ranging between (4.56 ± 0.3 - 21.67 ± 0.45) and (6.77 ± 0.4 - 20.41 ± 0.32) µM, respectively. Additionally, the recent work advocated that compound 5a showed the reference SAL at the É£-radiation dose of 10.0 kGy in the sterilization process without affecting its chemical structure. Finally, the in silico drug-likeness, toxicity properties, and molecular docking simulation were performed. Besides, the result exhibited good oral-bioavailability, lower toxicity prediction, and lower binding energy with good binding mode rather than the positive control.

Sulfaguanidine Hybrid with Some New Pyridine-2-One Derivatives: Design, Synthesis, and Antimicrobial Activity against Multidrug-Resistant Bacteria as Dual DNA Gyrase and DHFR Inhibitors.

Herein, a series of novel hybrid sulfaguanidine moieties, bearing 2-cyanoacrylamide 2a-d, pyridine-2-one 3-10, and 2-imino-2H-chromene-3-carboxamide 11, 12 derivatives, were synthesized, and their structure confirmed by spectral data and elemental analysis. All the synthesized compounds showed moderate to good antimicrobial activity against eight pathogens. The most promising six derivatives, 2a, 2b, 2d, 3a, 8, and 11, revealed to be best in inhibiting bacterial and fungal growth, thus showing bactericidal and fungicidal activity. These derivatives exhibited moderate to potent inhibition against DNA gyrase and DHFR enzymes, with three derivatives 2d, 3a, and 2a demonstrating inhibition of DNA gyrase, with IC50 values of 18.17-23.87 µM, and of DHFR, with IC50 values of 4.33-5.54 µM; their potency is near to that of the positive controls. Further, the six derivatives exhibited immunomodulatory potential and three derivatives, 2d, 8, and 11, were selected for further study and displayed an increase in spleen and thymus weight and enhanced the activation of CD4+ and CD8+ T lymphocytes. Finally, molecular docking and some AMED studies were performed.

Design, synthesis, antimicrobial activity and molecular docking studies of some novel di-substituted sulfonylquinoxaline derivatives.

2,3-Dioxo-1,2,3,4-tetrahydroquinoxaline-6-sulfonyl chloride 1 was prepared via reaction of o-phenylene diamine with oxalic acid followed by chlorosulfonation with excess chlorosulfonic acid. A series of new sulfonylquinoxaline derivatives 2-6 were obtained upon reacting compound 1 with different types of amines. 2,3-Dichloro-6-morpholinosulfonylquinoxaline derivative 6 was subjected to further chemical reactions to afford many derivatives of 6-morpholino 2,3-disubstitutedquinoxalines, thus reaction of compound 6 with different secondary amines yielded mono and di secondary aminoquinoxaline derivatives 7-10 depending on the reactivity difference of the two chlorine atoms. Hydrazinolysis of compound 7 furnished hydrazino quinoxaline derivatives 11a-c. Additionally triazolo and pyrazolyl quinoxaline derivatives 12-14 were obtained through the reaction of compound 11a with phenyl isothiocyanate, formylpyrazole and ethyl acetoacetate. All the synthesized compounds were screened for their antibacterial and antifungal activities. Compounds 7a, 9b, 10a, 10c, 10f and 11c showed good to moderate antimicrobial activity against the tested Gram-positive, Gram-negative bacteria and fungi with MIC values ranging from 2.44 to 180.14 µM. Their MBC values were also evaluated using the same tested microorganisms. Moreover, screening against multi-drug resistant strains revealed the promiscuity of these new derivatives, especially compound 7a that showed comparable antibacterial activity (MIC 4.91-9.82 µM) with Norfloxacin (MIC 2.44-9.80 µM). Furthermore, these compounds were evaluated as DNA Gyrase inhibitors and the obtained results were in the range of 15.69-23.72 µM. Immunomodulatory effect was also investigated and compounds 7a, 11c, 10f, 10c, 10a and 9b showed high immunostimulatory action with ratio (142.6 ± 0.4, 135.7 ± 0.5, 117.8 ± 0. 39, 112.5 ± 0. 83, 86.4 ± 0. 47, 72.8 ± 0. 77) respectively. Molecular docking studies of the promising derivatives into DNA Gyrase binding site proved the usefulness of hybridizing quinoxaline scaffold with SO2 and morpholine moieties as a hopeful strategy in designing new DNA Gyrase binding molecules.

Antimicrobial evaluation of thiadiazino and thiazolo quinoxaline hybrids as potential DNA gyrase inhibitors; design, synthesis, characterization and morphological studies.

A series of thiadiazino[5,6-b]quinoxaline and thiazolo[4,5-b]quinoxaline derivatives was designed and synthetized from the reaction of 2,3-dichloro-6-(morpholinosulfonyl)quinoxaline (2) with thiosemicarbazide or thiocarbohydrazide and thiourea derivatives to give nineteen quinoxaline derivatives 3-16. All the synthesized compounds were evaluated for in vitro antimicrobial potential against various bacteria and fungi strains that showed considerable antimicrobial activity against tested microorganisms. The most potent compounds 2, 7, 9, 10, 12 and 13c were exhibited bactericidal activity, in addition to fungistatic activity by dead live assay. Moreover, these compounds showed a significant result against all multi-drug resistance (MDRB) used especially compound 13c that displayed the best results with MICs of MDRB (1.95, 3.9, 2.6, 3.9 µg/mL) for stains used in this study, compared with Norfloxacin (1.25, 0.78, 1.57, 3.13 µg/mL). Also, cytotoxicity on normal cell (Vero cells ATCC CCL-81) by MTT assay was performed with lower toxicity results. Additionally, morphological studies, immunostimulatory potency and DNA gyrase inhibition assay of most active compounds was done. A molecular docking study has also been carried out to support the effective binding of the most promising compounds at the active site of the target enzyme S. aureus DNA gyrase (2XCT).