Four dioxomolybdenum(VI) complexes were synthesized by reacting [MoO2(acac)2] with N-ethyl-2-(5-bromo-2-hydroxybenzylidene) hydrazinecarbothioamide (1), N-ethyl-2-(5-allyl-3-methoxy-2-hydroxybenzylidene) hydrazinecarbothioamide (2), N-methyl-2-(3-tert-butyl-2-hydroxybenzylidene) hydrazinecarbothioamide (3), and N-ethyl-2-(3-methyl-2-hydroxybenzylidene) hydrazinecarbothioamide (4). The molecular structures of 1, 2, and all the synthesized complexes were determined using single crystal X-ray crystallography. The binding properties of the ligand and complexes with calf thymus DNA (CT-DNA) were investigated via UV, fluorescence titrations, and viscosity measurement. Gel electrophoresis revealed that all the complexes cleave pBR 322 plasmid DNA. The cytotoxicity of the complexes were studied against the HCT 116 human colorectal cell line. All the complexes exhibited more pronounced activity than the standard reference drug 5-fluorouracil (IC50 7.3μM). These studies show that dioxomolybdenum(VI) complexes could be potentially useful in chemotherapy.
Two nickel(II) complexes with formula NiL1 and NiL2 (HL1 = S-allyl-4-methoxybenzylidene hydrazinecarbodithioate, HL2 = S-allyl-1-napthylidenehydrazinecarbodithioate) have been synthesized and characterized by elemental analysis, FT-IR, NMR, UV-vis spectroscopy and ESI mass spectrometry. The crystal structure of complex 1 has been determined by single crystal X-ray diffractometry. Both HL1 and HL2 ligands are coordinated to the metal in thiolate form. In complexes, squareplanar geometry of the nickel is coordinated with two bidentate ligand units acting through azomethine nitrogen and thiolato sulfur atoms. To explore the potential medicinal value of the complexes with calf thymus DNA and bovine serum albumin (BSA) were studied at normal physiological conditions using fluorescence spectral techniques. The DNA binding constant values of the complexes were found in the range from 5.02 × 10(4), 3.54 × 10(4), and the binding affinities are in the following order 1 > 2. In addition, nickel complexes 1 and 2 shows better binding propensity to the bovine serum albumin (BSA) protein, giving a Ksv value 5.8 × 10(4), 4.47 × 10(4) respectively. From the oxidative cleavage of the complexes with pBR322 DNA, it is inferred that the effects of cleavage are dose-dependent. In addition, in vitro cytotoxicity of the complexes assayed against Vero and HeLa cell lines have shown higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing cancer cells even at various concentrations.
New derivatives of thiosemicarbazone Schiff base with isatin moiety were synthesized L1-L6. The structures of these compounds were characterized based on the spectroscopic techniques. Compound L6 was further characterized by XRD single crystal. The interaction of these compounds with calf thymus (CT-DNA) exhibited high intrinsic binding constant (k(b)=5.03-33.00×10(5) M(-1)) for L1-L3 and L5 and (6.14-9.47×10(4) M(-1)) for L4 and L6 which reflect intercalative activity of these compounds toward CT-DNA. This result was also confirmed by the viscosity data. The electrophoresis studies reveal the higher cleavage activity of L1-L3 than L4-L6. The in vitro anti-proliferative activity of these compounds against human colon cancer cell line (HCT 116) revealed that the synthesized compounds (L3, L6 and L2) exhibited good anticancer potency.