New anticancer zinc(II) complexes comprising thiosemicarbazones of saturated ring: structure, DNA/protein binding, DNA cleavage, topoisomerase‐1 inhibition and anti‐proliferation studies

Abstract

The reaction of the thiosemicarbazones (CH2)4CNN(H)C(S)NHR (R = H, Me) with zinc(II) acetate in methanolic solution proceeds readily under mild conditions to form stable mononuclear complexes Zn[(CH2)4CNNC(S)NHR]2. DNA interaction studies show that the zinc(II) complexes bind to DNA via groove mode and exhibit efficient DNA cleavage activity in the presence of hydrogen peroxide. Also, the complexes display a binding affinity to bovine serum albumin protein with KBSA values of ca 105 M−1. Topoisomerase catalytic inhibition studies suggest that both complexes are efficient topoisomerase‐I impeders. Furthermore, the anti‐proliferative effects of the two complexes on five human tumor cell lines (Caki‐2, MCF‐7, CaSki, NCI‐H322M and Co‐115) indicate that both complexes have the potential to act as effective anticancer drugs. Copyright © 2016 John Wiley & Sons, Ltd.