Spectroscopic characterization, antioxidant and antitumour studies of novel bromo substituted thiosemicarbazone and its copper(II), nickel(II) and palladium(II) complexes

Exploring the antimalarial and antioxidant efficacy of transition metal(II) chelates of thiosemicarbazone ligands: spectral investigations, molecular docking, DFT, MESP and ADMET

Malaria, a relentless and ancient adversary, continues to cast its shadow over vast swathes of the globe, afflicting millions of people and have a heavy toll on human health and well-being. Despite substantial progress in the fight against this parasitic disease in recent decades, malaria still persists as a substantial global health concern, especially in some specific region which have limited resources and vulnerable populations. Thus, to ascertain an combating agent for malaria and its associated dysfunction, 4-(4-ethylphenyl)-3-thiosemicarbazide and benzaldehydes based two new thiosemicarbazone ligands (1-2) and their cobalt(II), nickel(II), copper(II), zinc(II) metal complexes (3-10) were synthesized in the present research work. The synthesized compounds were comprehensive characterized through spectral and physical investigations, demonstrating octahedral stereochemistry of the complexes. Further, the antimalarial and antioxidant potential of the compounds (1-10) were analyzed by micro assay and DPPH assay protocols, respectively, to examine the therapeutic aspect of the compounds. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. The complexes (5), (6), (10) shows significant efficiency for malarial and oxidant dysfunctions whereas Zn(II) complex (6) exhibit highest potency with 1.02 ± 0.07 and 2.28 ± 0.05 µM IC50 value. Furthermore, to support the highest antimalarial potency of the (3-6) complexes and their associated ligand (1), the computational studies like molecular docking, DFT, MESP and ADMET analysis were executed which were supported the biological efficacy of the complex (6) by providing numerous parameters like binding interaction electronegativity, electrophilicity, HOMO value and electron density.

Design, synthesis, biomedical investigation, DFT calculation and molecular docking of novel Ru(II)-mixed ligand complexes

A novel series of bioactive water-soluble mononuclear Ru(II)-mixed ligand complexes of 2,2'-bipyridyl and V-shaped Schiff base ligands were synthesized and structurally characterized. Biomedical activities of Ru(II) complexes have been tested in view of antioxidant activities, interaction with calf thymus DNA (CT-DNA), and anticancer performance. The optimized structure of these complexes has been further supported by density functional theory (DFT) calculations. Further, validation of the interaction studies of some complexes was accomplished by carrying out molecular docking studies with DNA using molecular operating environment (MOE) software are reported.Communicated by Ramaswamy H. Sarma.

Structurally different mono-, bi- and trinuclear Pd(ii) complexes and their DNA/protein interaction, DNA cleavage, and anti-oxidant, anti-microbial and cytotoxic studies

A series of new structurally different Pd(ii) complexes was obtained by the reactions between K₂[PdCl₄], 3-methoxysalicylaldehyde-4(N)-substituted thiosemicarbazone [H₂L1–H₂L4] and bis(diphenylphosphino)ethane [dppe].

[Cytotoxic effect of palladium (II) inclusion compounds in beta-cyclodextrin]

INTRODUCTION

Thiosemicarbazones and palladium (II) complexes have antineoplastic activities with mild side effects, for which they are considered new alternative antineoplastic drugs. However, the IC50 ranges of these complexes vary due to differences in their structure and solubility and their sensitivities for various cellular targets. Beta-cyclodextrin is an additive used to improve the solubility and stability of various drugs for therapeutic use, but the combination of beta-cyclodextrin with palladium (II) complexes and thiosemicarbazones has not been tested yet.

OBJECTIVE

To study the cytotoxic effect of palladium (II) inclusion complexes in beta-cyclodextrin.

MATERIALS AND METHODS

We tested the cytotoxic activity of palladium complexes combined with beta-cyclodextrin in the breast cancer cell line MCF-7 using a sulforhodamine B assay.

RESULTS

We tested the antiproliferative activity of palladium (II) complexes with and without the ligands MePhPzTSC and Ph2PzTSC and with and without beta-cyclodextrin in MCF-7 cells and compared them to that of cisplatin. All combinations showed antiproliferative activity; however, the activity was greater for the combinations that included beta-cyclodextrin: ([Pd (MePhPzTSC) 2] • ß-CD and [Pd (Ph2PzTSC) 2] • ß-CD), at concentrations of 0.14 and 0.49 μM, respectively. The IC50 for this complex was 5-fold lower than that of the ligand-free combinations (1.4 and 2.9 μM, respectively). The IC50 for free palladium (II) complex was 0.571.24 μM and that for cisplatin was 6.87 μM.

CONCLUSIONS

Beta-cyclodextrin significantly enhanced the cytotoxic activities of palladium (II) complexes and thiosemicarbazones probably by improving their solubility and bioavailability. The addition of beta-cyclodextrin is a possible strategy for designing new anticancer drugs.

Crystal structure of bis-(aceto-phenone 4-benzoyl-thio-semicarbazonato-κ(2) N (1),S)nickel(II)

In the asymmetric unit of the title complex, [Ni(C16H14N3OS)2], the nickel ion is tetra-coordinated in a distorted square-planar geometry by two independent mol-ecules of the ligand which act as mononegative bidentate N,S-donors and form two five-membered chelate rings. The ligands are in trans (E) conformations with respect to the C=N bonds. The close approach of hydrogen atoms to the Ni(2+) atom suggests anagostic inter-actions (Ni⋯H-C) are present. The crystal structure is built up by a network of two C-H⋯O inter-actions. One of the inter-actions forms inversion dimers and the other links the mol-ecules into infinite chains parallel to [100]. In addition, a weak C-H⋯π inter-action is also present.

In vitro antiproliferative activity of palladium(ii) thiosemicarbazone complexes and the corresponding functionalized chitosan coated magnetite nanoparticles

Magnetite functionalized nanoparticles with Pd(L³)₂ and Pd(L⁴)₂ show antiproliferative activity against DU-145 and HuTu80; Pd(L²)₂ is found to be a promising pharmacological agent.

cis-Dioxomolybdenum(VI) complexes of a new ONN chelating thiosemicarbazidato ligand; synthesis, characterization, crystal, molecular structures and antioxidant activities

5-Chloro-4-methyl-2-hydroxybenzophenone S-propyl-4-phenyl-thiosemicarbazone (H2L) and its cis-dioxomolybdenum(VI) complexes, in the general formula [MoO2(L)R-OH)] (R: methyl, 1; ethyl, 2; n-propyl, 3; n-butyl, 4; n-pentyl, 5), were synthesized and characterized by micro analysis, electronic, infrared and (1)H and (13)C NMR spectra. The crystal structures of complexes, 1 and 3, have been solved by direct methods (SIR92) and refined to the residual indexes R1=0.098 and R1=0.052 respectively. Complexes 1 and 3 are crystallized in the triclinic space group P-1 with Z=2. The crystal study of complex 1 showed the first example of intermolecular hydrogen bond for this type of molybdenum-thiosemicarbazone complexes. The hydrogen bond is between the hydroxyl proton of attached alcohol and an oxo oxygen (in MoO2(2+) unit) of another complex molecule, and its bond distance (1.767(1)Å) is shorter than from the σ-coordination bonds in complex 1. Antioxidant activities of the compounds were determined by using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. Ligand showed 23.61% DPPH radical scavenging activity at 250 mg/L concentration. Cupric Reducing Antioxidant Capacity (CUPRAC) was also evaluated and trolox-equivalent antioxidant capacity (TEAC) values were found for ligand, 1 and 3 as 0.51, 0.33 and 0.30 respectively.