Novel 2-amino-1,4-naphthoquinone hybrids: Design, synthesis, cytotoxicity evaluation and in silico studies

In the present work, a novel series of 2-amino-1,4-naphthoquinones bearing oxyphenyl moiety (5a-5m) were designed and synthesized via a two-step route and evaluated for their in vitro cytotoxic activity against three different cancer cell lines (MCF-7, HL-60 and U937) and normal human cell line (HEK-293) by MTT assay. Compounds 5b (4-nitro-benzyl-) and 5k (4-bromo-benzyl-) were identified to possess the highest cytotoxic activity against MCF-7 cancerous cells (IC₅₀ values of 27.76 and 27.86 μM, respectively). At the same time, none of the compounds exert significant toxicity against HEK-293 normal human kidney cells. Cell cycle analysis showed that the selected derivatives increased the population of MCF-7 cells in the S phase at 25 and 50 μM concentrations. Annexin V-FITC/PI staining assay also confirmed that compounds 5b and 5k induced apoptosis in the cell death pathway. Molecular docking and molecular dynamics studies were also performed to evaluate the probable interactions between the hybrids and human ATP binding domain of topo IIα protein. Our findings may provide new insight for further development of novel naphthoquinone-containing compounds.