Heterocyclic compounds can specifically regulate bacterial development by targeting specific bacterial enzymes and metabolic pathways. The ESKAPE pathogens are multidrug-resistant and cause nosocomial infections, which is one of the greatest challenges in clinical practice. The search for novel agents to combat resistant bacteria has become one of the most important areas of antibacterial research today. Heterocyclic compounds offer a valuable strategy in the fight against resistance as they can be designed to interact with bacterial targets that are less prone to developing resistance mechanisms. Bacterial histidine kinases (HKs), which are a component of two-component bacterial systems, are a promising target for new antibacterial compounds. We have designed and synthesized novel indole derivatives as antibacterial agents. Among the series, indole-coumarin (4b) and bisindole (4e) have shown the best inhibitory activity against S. aureus. Further, in silico docking studies show that compounds 4b and 4e could target histidine kinases in bacteria.

Telomere shortening and the induction of senescence and/or cell death may result from inhibition of telomerase activity in cancer cells. Herein, the properties of carbazole–triazole compounds targeting telomerase in human breast cancer cells are explored. All derivatives were evaluated for loss of viability in MCF-7 breast cancer cells, with compound 5g identified as the most potent within the examined series. Green synthesis was employed using water, a reusable nano-Fe₂O₃-catalyzed reaction, and an electrochemical method for the synthesis of tetrahydrocarbazole and triazoles. The crystal data of compound 4 is also reported. Furthermore, in silico analysis predicted that compound 5g may target human telomerase. Molecular docking analysis of compound 5g towards hTERT predicted a binding affinity of −6.74 kcal/mol. In flow cytometry assays, compound 5g promoted apoptosis and cell cycle arrest in the G2-M phase. Finally, compound 5g inhibited the enzymatic activity of telomerase in human breast cancer cells. In conclusion, a green synthesized series of carbazole–triazoles that target telomerase in cancer cells is reported.