Development of new (E)-N'-substituted benzylidene-5-(piperazin-1-yl) benzofuran-2-carbohydrazides: A potent moiety as antimicrobial agents

In this work, we report for the first-time synthesis of some new (E)-N'-substituted benzylidene-5-(piperazin-1-yl) benzofuran-2-carbohydrazides (9a-9r) from new scaffold moiety 5-(piperazin-1-yl)-1-benzofuran-2-carbohydrazide (8) as the antimicrobial agents. All newly synthesized compounds were characterized by FT-IR, 1H-NMR, 13C-NMR, and mass spectrometry. The antimicrobial activity of the compounds was evaluated using the agar well diffusion method. The minimum inhibitory concentration (MIC) of the synthesized compounds was determined using serial dilution concentrations of 10 mu g/mL, 20 mu g/mL, 40 mu g/mL, 80 mu g/mL, 160 mu g/mL and 320 mu g/mL respectively. Compounds (9a-9r) were tested against gram-positive S. aureus and gram-negative E. Coli and P. aeruginosa for their inhibitory effects as anti-bacterial agents and C. albicans for their inhibitory effects as antifungal agents. The synthesized series was found to be most active against gram-positive bacterial strain S. aureus wherein compounds 9g and 9j having MIC 40 mu g/mL showed the best activity. Out of the series, compound 9h was found to be moderately active with MIC 320 mu g/mL against antifungal strain C. albicans. The docking studies also suggested compounds 9g and 9j to be potent inhibitors of DNA gyrase in S. aureus bacterial strain. The purity of synthesized compounds was confirmed by the high-performance liquid chromatography (HPLC) method and thin layer chromatography (TLC) method.