Novel 3-Substituted 8-Methoxycoumarin Derivatives as Anti-Breast Cancer Drugs

Scientists have been interested in hybrid coumarin derivatives due to their wide clinical anticancer use. Herein, ethyl 8-methoxycoumarin-3-carboxylate (Compound 1) served as the starting material for the synthesis of a series of novel hybrid coumarin derivatives (Compounds 3–6). Their structure was determined using 13C NMR, 1H NMR, elemental analysis, and mass spectrometry. The in vitro cytotoxic activities of coumarin derivatives (Compounds 3, 5, and 6) and brominated coumarin derivatives (Compounds 4, 8, and 9) against MCF-7 and MDA-MB-231 were evaluated. Several substances have been identified as promising candidates for future study, especially Compound 6 due to its potent activity against β-tubulin (TUB) polymerization, sulfatase, and aromatase enzymes. It also has a role in inducing cell-cycle arrest at the S phase in the MCF-7 cell line, as well as apoptosis.