Novel Zn(II)-complex with hybrid chalcone-thiosemicarbazone ligand: Synthesis, characterization, and inhibitory effect on HTLV-1-infected MT-2 leukemia cells.

Chalcone and thiosemicarbazone have attracted attention due to their easy synthetic procedure and high success in the development of antiviral and antitumor, however, there are few biological data on the evaluation of chalcone-thiosemicarbazone hybrids and their complexation with metal ions. In this sense, the present work reports the synthesis and characterization of the hybrid (Z)-2-((E)-3-(4-chlorophenyl)-1-phenylallylidene)hydrazine-1-carbothioamide (CTCl) and its Zn(II)-complex (CTCl-Zn). The compounds were cell-based evaluated in terms of cytotoxicity against human T-cell lymphotropic virus type 1 (HTLV-1) infected leukemia cells (MT-2) and the experimental data were correlated with molecular docking calculations. The ligand and Zn(II)-complex were easily synthesized with a good yield - 57% and 79%, respectively. The dynamic of E/Z isomers with respect to the imine bond configuration of CTCl was evidenced by 1H NMR experiments in DMSO‑d6, while the X-ray diffraction of CTCl-Zn showed that Zn(II) ion is tetracoordinated to two ligands in a bidentate mode and the metal ion lies on an intermediate geometry between the see-saw and trigonal pyramid. The ligand and complex exhibited low toxicity and the Zn(II)-complex is more cytotoxic than the ligand, with the corresponding IC50 value of 30.01 and 47.06 μM. Both compounds had a pro-apoptotic effect without the release of reactive oxygen species (ROS) and they can interact with DNA via minor grooves driven by van der Waals forces.