Design, Synthesis, In Vitro Biological Evaluation, and In Silico Analyses of Novel Pyrano[3,4‑b]indole-Containing Compounds as Promising Multitarget Candidates for Alzheimer’s Disease and Cancer Therapy

Abstract

Alzheimer’s disease (AD) is a neurodegenerative disease associated with decreased activity of the cholinergic system in the brain. Identifying a drug that has no side effects and can prevent or delay the progression of this neurodegenerative disease is crucial. In this study, 11 novel pyrano[3,4-b]indole derivatives (ECA-ECM) were designed and synthesized as AChE and BChE inhibitors, and their structures were elucidated by spectroscopic analyses. Enzyme activity studies were conducted in vitro. Inhibitory potentials for both cholinesterase enzymes were determined by in silico analyses, and protein–ligand interactions were elucidated. The ECB compound (AChE IC50 = 35.31 ± 0.81 nM and BChE IC50 = 28.91 ± 0.19 nM) is a potential candidate as a dual AChE/BChE inhibitor. These findings indicate that the synthesized pyrano[3,4-b]indole derivatives have inhibitory potential for AD. The cytotoxic activities of the synthesized compounds were evaluated in vitro. The ECK compound showed a strong cytotoxic effect in five different human cancer cell lines in the ranging concentrations from 10.37 ± 1.43 to 29.34 ± 1.71 μM. The ECD compound exhibited strong cytotoxic activity at a concentration of 9.27 ± 0.97 μM in the colon cancer cell line. The cytotoxic activities of ECK and ECM were found to be below 25 μM in four human cancer cell lines. In silico analyses, including molecular docking, molecular dynamics simulations, and binding free energy calculations, confirmed that the synthesized compounds are potential candidates targeting AChE and BChE. Consequently, the synthesized compounds showed promising results for the treatment of AD and cancer.