Synthesis, cytotoxic activity and DNA-interaction studies of novel anthraquinone–thiosemicarbazones with tautomerizable methylene group

A series of novel anthraquinone–thiosemicarbazone derivatives in a tautomerizable keto-imine form was synthesized and tested for their in vitro cytotoxic activity against human cancer cells (HeLa, MDA-MB-361, MDA-MB-453, K562, A549) and human normal MRC-5 cells. Several compounds efficiently inhibited cancer cell growth at micromolar concentrations, especially against K562 and HeLa cells. As determined by flow cytometric analysis, anthraquinone–thiosemicarbazone caused significant increase in the number of sub-G1 phase of HeLa cells and apoptosis in a concentration-dependent manner. Also, inhibition of caspase-3, -8, and -9 with specific caspase inhibitors reduced the apoptosis mediated by the tested compounds in HeLa cells. All anthraquinone–thiosemicarbazones exhibit calf thymus DNA-binding activity, but no cleavage of plasmid DNA was observed. [Display omitted] •Tautomerizable anthraquinone–thiosemicarbazones were prepared and tested for their cytotoxic potential.•The compounds promoted apoptosis by a caspase dependent manner in cervix adenocarcinoma HeLa cells.•All derivatives exhibit calf thymus DNA-binding activity, but no cleavage of plasmid DNA was detected.