New heterocyclic chalcones. Part 6. Synthesis and cytotoxic activities of 5- or 6-(3-aryl- 2-propenoyl)-2(3H)-benzoxazolones

Abstract

A number of chalcones bearing an oxazole cycle were synthesized by Claisen-Schmidt condensation of 5-acetyl-2(3 H )-benzoxazolone or 6-acetyl-2(3 H )-benzoxazolone and the appropriate aldehydes. The chalcones were evaluated for cytotoxic activity against several tumor cell lines - BV-173 (human B cell precursor leukemia), MCF-7 and MDA-MB-231 (human breast adenocarcinoma) using the MTT-dye reduction assay. The tested compounds exhibit concentration- dependent cytotoxic effects at micromolar concentrations. Exposure of the BV-173 tumor cell line to compound 3f results in strong monoand oligonucleosomal fragmentation of genomic DNA, as evidenced by a 'cell death detection' ELISA kit, which unambiguously indicates that the induction of apoptosis is implicated in the cytotoxic mode of action of the tested compound.