The biological significance of benzopyran-4-ones as cytotoxic agents against multi-drug resistant cancer cell lines and isoxazoles as anti-inflammatory agents in cellular assays prompted us to design and synthesize their hybrid compounds and explore their antiproliferative activity against a panel of six cancer cell lines and two normal cell lines. Compounds 5a-d displayed significant antiproliferative activities against all the cancer cell lines tested, and IC50 values were in the range of 5.2-22.2 μM against MDA-MB-231 cancer cells, while they were minimally cytotoxic to the HEK-293 and LLC-PK1 normal cell lines. The IC50 values of 5a-d against normal HEK-293 cells were in the range of 102.4-293.2 μM. Compound 5a was screened for kinase inhibitory activity, proteolytic human serum stability, and apoptotic activity. The compound was found inactive towards different kinases, while it completely degraded after 2 h of incubation with human serum. At 5 μM concentration, it induced apoptosis in MDA-MB-231 by 50.8%. Overall, these findings suggest that new benzopyran-4-one-isoxazole hybrid compounds, particularly 5a-d, are selective anticancer agents, potentially safe for human cells, and could be synthesized at low cost. Additionally, Compound 5a exhibits potential anticancer activity mediated via inhibition of cancer cell proliferation and induction of apoptosis.
Keywords: antiproliferative; apoptosis; benzopyranone; chromone; drug discovery; isoxazole; protein tyrosine kinase.