Novel cyclohepta[b]thiophene derivative incorporating pyrimidine, pyridine, and chromene moiety as potential antimicrobial agents targeting DNA gyrase

Abstract

The emergence of drug-resistant microbes is responsible for high morbidity and mortality worldwide. In our endeavors to cultivate novel and effectual antimicrobial agents, we present the triumphant synthesis of a novel class of cyclohepta-thieno-pyrimidins 4-8, cyclohepta[b]thiophene appended 2-imino-2H-chromene-3-carboxamide and 3-imino-3H-benzo[f]chromene-2-carboxamide derivatives 9-11 molecules, to enrich their biological behavior. The desired molecules had undergone in-vitro appraisal for their antimicrobial activity, demonstrating encouraging results. Besides, the time-kill kinetics, antibiofilm activity and the DNA gyrase inhibition of the active thiophene compounds were evaluated. The DNA gyrase inhibition by the active thiophenes was also determined with IC50 values to range between (5.3-18.7µM) compared with Levofloxacin and Ciprofloxacin. Also, the sum of the Fractional Inhibitory Concentration Index (ΣFICI) was used to assess synergy between thiophenes and Levofloxacin. Additionally, the antimicrobial activity of the most active thiophene derivative was analyzed after ɣ -irradiation. Moreover, the in-silico prediction methodology was contemplated for foretelling the physicochemical, pharmacokinetic and ADME traits of the most active synthesized compounds and the standard reference drugs: Levofloxacin and Ciprofloxacin. The docking examination was carried out for the most promising derivatives 1, 2, 3, 4, 9, Novobiocin, and Levofloxacin inside the active site of DNA gyrase, and their respective docking scores were contrasted with the scores of the above-mentioned standard drugs.