Benzamides of 2-(aminophenyl)benzimidazoles and 2-(aminophenyl)indoles as Anticancer Scaffolds: Synthesis, In Silico and In Vitro Evaluation.

Background/Objectives: Indoles and benzimidazoles are important nitrogen-containing heterocyclic scaffolds and are a cornerstone of synthetic drugs. In this study, benzamides of 2-aminophenylindoles and 2-aminophenylbenzimidazoles were synthesized and evaluated for their potential. Further, they were also subjected to computational studies for their ADMET profiling and binding with target proteins. Methods: The synthesized compounds were characterized by ATR-FTIR, 1H NMR, 13C NMR and electrospray ionization mass spectroscopy (ESI-MS). They were screened for their in vitro antibacterial activity by the Microplate Alamar Blue Assay (MABA) and for their anticancer potential by the MTT assay against the HeLa, PC3 and 3T3 cell lines. Further, the compounds were assessed for their ADMET profiles by the Deep-PK platform, and binding with selected kinases was assessed by AutoDock Vina v1.2.7, followed by MD simulations in GROMACS. Density functional theory (DFT) calculations were also performed to investigate the electronic properties of the synthesized compounds. Results: All synthesized compounds were inactive in antibacterial assays and mildly active against cancer cells. N-[4-(1H-benzimidazol-2-yl-phenyl]benzamide (4-APB-B) exhibited good activity against the HeLa cell line (IC50: 5.48 ± 0.01 µM) while showing very low cytotoxicity against the 3T3 cell line (selectivity index: 10.7), against which doxorubicin was highly active, indicating selectivity towards specific cancer cells. Docking studies indicated favorable binding affinities towards the selected kinase targets. Further, ligands with the best binding affinities in docking studies were subjected to MD simulations of 100 ns, and DFT studies were also performed to assess the electronic properties of the synthesized compounds. Conclusions: Our study provides a pathway for the synthesis of 2-phenylbenzimidazoles and 2-phenylindoles and demonstrates that the synthetic compound 4-APB-B possesses remarkable selective cytotoxic activity and can serve as a lead molecule for further development into a successful anticancer agent.