Synthesis, characterization, anti-tumor activity, photo-luminescence and BHb/HHb/Hsp90 molecular docking of zinc(II) hydroxyl-terpyridine complexes

Abstract

Six zinc(II) complexes [Zn(Br)2L1] (1), [Zn(Br)2L2] (2) and [Zn(Br)2L3] (3), [Zn(I)2L1] (4), [Zn(I)2L2] (5) and [Zn(I)2L3] (6) have been obtained by the reactions of ZnBr2 or ZnI2 with p-hydroxyl-4′-phenyl-terpyridine(L1), m-hydroxyl-4′-phenyl-terpyridine(L2) and o-hydroxyl-4′-phenyl-terpyridine(L3), which were characterized by elemental analysis, FT-IR and NMR, as well as single crystal X-ray diffraction. Comparing to cisplatin, compounds 1–6 show higher antiproliferative activity against human lung carcinoma cell line (A549), human ileocecal colorectal adenocarcinoma cell line (HCT-8) and human breast cancer cell line (MCF-7). As the concentration of compounds 1–6 increases in the BHb/HHb-compound system, the fluorescent intensity of bovine hemoglobin (BHb) and human hemoglobin (HHb) reduces with a static quenching mechanism. The binding constant and the number of binding sites for the interaction of the compounds with BHb and HHb were calculated. Molecular docking studies suggest that the binding process of these compounds with heat shock protein 90 (Hsp90), BHb and HHb is a spontaneous molecular interaction process, in which van der Waals forces and hydrogen bonds play major roles, and π-π interaction also has influence on binding process. These results suggest that compounds 1–6 can be candidates for further evaluation as chemotherapeutic agents against human tumor.