Antitumor Effect of Some 3d-Metal Complexes of N-Isonicotinoyl-N'-o-Hydroxythiobenzhydrazide

A new ligand, N-isonicotinoyl-N'-o-hydroxythiobenzhydrazide (H_2Iotbh), forms complexes [Co(Iotbh)(H_2O)_2], [M(Iotbh)] [M Ni(II) Cu(II) and Zn(II)] and [M(Iotbh-H)(H_2O)_2] [M = Mn(III), Fe(III)], which were characterized by various physico-chemical techniques. DMSO solution of metal complexes was observed to inhibit the growth of tumor in vitro, whereas the ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor-bearing mice. Tumor-bearing mice administered with the solution of metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implications of the H_2lotbh and its metal complexes in tumor regression and tumor growth associated immunosuppression.