Synthesis and biological activity of new indole based derivatives as potent anticancer, antioxidant and antimicrobial agents

Indoles have very critical roles to design new biologically active molecules in medicinal chemistry. They display higher biological activities or create new biological properties when compared to the other heteroaromatic compounds. In the present study, 1-ethyl-2-phenyl-3-(thiophen-2-yl)-1H-indole (3), 8-ethyl-8H-benzo[a]thieno[3,2-c]carbazole (4), 1-ethyl-2-phenyl-3-(5-(phenylethynyl)thiophen-2-yl)-1H-indole (6) and 1-ethyl-3-(furan-2-yl)-2-phenyl-1H-indole (7) are prepared via Pd-catalyzed cross-coupling reactions and iodocyclization reactions. It was determined that compound 3 and 7 were also seemed to be better drug candidates at the end of in silico evaluation. Furthermore, compound 7 provided the best antibacterial and antifungal activity against the test indicator strains. It showed a potent antifungal effect on Aspergillus niger ATCC 16404 (MIC: 1.17 µg mL−1; MFC: 2.7 µg mL−1). In addition, while compounds 3, 6 and 7 showed significantly high molybdenum reducing activity compared to trolox, 7 exhibited almost the same antioxidant activity (EC50 = 7.1 µM) compared to the trolox standard (EC50 = 5.07 µM).