Molecular hybridization has a wide application in medicinal chemistry to obtain new biologically active compounds. New isatin-indole molecular hybrids 5a-n have been synthesized and characterized by various spectroscopic tools. The in vitro antimicrobial potential of the prepared compounds 5a-n was assessed using diameter of the inhibition zone (DIZ) and minimum inhibitory concentration (MIC) assays against a panel of Gram-negative bacteria, Gram-positive bacteria and fungi. Most of the synthesized compounds 5a-n showed weak activities against Gram-negative bacteria while compounds 5b and 5c exhibited good activities against Gram-positive bacteria. On the other hand, compound 5j emerged as the most active compound towards Candida albicans (C. albicans), with an MIC value of 3.9 µg/mL, and compound 5g as the most active congener towards Asperagillus niger (A. niger), with an MIC value of 15.6 µg/mL. Moreover, compound 5h manifested the best anti-P. notatum effect, with an MIC value of 7.8 µg/mL, making it equipotent with compound 5g.
Keywords: 5-methoxyindole; antibacterial; antifungal; isatin.