Synthesis and anticancer activities of thiosemicarbazones derivatives of thiochromanones and related scaffolds

A series of novel thiosemicarbazone analogs (4a–t, 6a–j) were synthesized and evaluated for their cytotoxic activities. The obtained results showed that thiochromanone-based thiosemicarbazones substituted primarily at the C-8 position exhibited higher cytotoxicity than the corresponding 1,1-dioxo-thiochromanone-, benzothiazepine-, and 1,1-dioxo-benzothiazepine-based analogs. Significantly, compound 4c (8-fluoro thiochromanone thiosemicarbazone) was found to be the most active and exhibited potent cytotoxicity against the MCF-7, SK-mel-2, and DU145 cancer cell lines, with IC50 values of 0.42, 0.58, and 0.43 µM, respectively. In addition, the mechanism of compound 4c induced MCF-7 cell apoptosis was preliminarily investigated through cell cycle, Annexin V-FITC/PI staining, and ROS assays, indicating that compound 4c may exert its anticancer property through ROS-mediated apoptosis.