Microbial DNA gyrase
is regarded as an outstanding microbial target.
Hence, 15 new quinoline derivatives (5–14) were designed and synthesized. The antimicrobial activity of the
afforded compounds was pursued via in vitro approaches.
The investigated compounds displayed eligible MIC values, particularly
against G-positive Staphylococcus aureus species. Consequently, an S. aureus DNA gyrase supercoiling assay was performed, using ciprofloxacin
as a reference control. Obviously, compounds 6b and 10 unveiled IC50 values of 33.64 and 8.45 μM,
respectively. Alongside, ciprofloxacin exhibited an IC50 value of 3.80 μM. Furthermore, a significant docking binding
score was encountered by compound 6b (−7.73 kcal/mol),
surpassing ciprofloxacin (−7.29 kcal/mol). Additionally, both
compounds 6b and 10 revealed high GIT absorption
without passing the blood brain barrier. Finally, the conducted structure−activity
relationship study assured the usefulness of the hydrazine moiety
as a molecular hybrid for activity either in cyclic or opened form.