Developing a Copper(II) Isopropyl 2-Pyridyl Ketone Thiosemicarbazone Compound Based on the IB Subdomain of Human Serum Albumin-Indomethacin Complex: Inhibiting Tumor Growth by Remodeling the Tumor Microenvironment

To develop a next-generation metal agent and dual-agent multitargeted combination therapy, we developed a copper (Cu) compound based on the properties of the human serum albumin (HSA)-indomethacin (IND) complex to remodel the tumor microenvironment (TME). We optimized a series of Cu(II) isopropyl 2-pyridyl ketone thiosemicarbazone compounds to obtain a Cu(II) compound (C4) with significant cytotoxicity and then constructed an HSA-IND-C4 complex (HSA-IND-C4) delivery system. IND and C4 bind to the hydrophobic cavities of the IB and IIA domains of HSA, respectively. In vivo, the HSA-IND-C4 not only showed enhanced antitumor efficacy relative to C4 and C4 + IND but also improved their targeting ability and decreased their side effects. The antitumor mechanism of C4 + IND involved acting on the different components of the TME. IND inhibited tumor-related inflammation, while C4 not only induced apoptosis and autophagy of cancer cells but also inhibited tumor angiogenesis.

A novel water-soluble thiosemicarbazone Schiff base ligand and its complexes as potential anticancer agents and cellular fluorescence imaging

A novel fluorescent ligand (H₂LCl⋅1.5CH₃OH, 1) was synthesized and metal complexes of 1 with Mn(II), Fe(III), Ni(II), Cu(II), and Zn(II) were obtained as Mn(HL)₂Cl₂ (2), Fe(HL)₂Cl₃⋅3H₂O (3), Ni(L)(HL)Cl⋅8H₂O (4), Cu(HL)Cl₂⋅4H₂O (5), Zn(H₂L)Cl₃ (6), respectively. These compounds were identified by spectroscopic methods, elemental analysis, molar conductivity, and single-crystal X-ray crystallography. According to the crystal structure of 4 nickel (II), center is surrounded by two ligands in a distorted octahedral geometry. The ligand and its complexes are soluble in water and have excellent stability. In vitro anti-proliferative activity of these compounds was evaluated against human breast adenocarcinoma (MCF-7) and human lipo-sarcoma (SW-872) as cancer cells and human fibroblasts (HFF-2) as normal cells by MTT assay. Interestingly, complex 5 exhibited excellent activity against both cancer cells with low IC₅₀ value 22.18 ± 0.35 μg/mL (35.66 ± 0.56 μM) for SW-872 and 79.41 ± 3.54 μg/mL (127.6 ± 5.69 μM) for MCF-7 among the compounds and in comparison with paclitaxel (PTX) which acts finely. Morphological changes were evaluated by flow cytometry that revealed apoptosis is the main cause of cell death. Likewise, cell cycle studies indicated the cell cycle arrest in the G₁ and S phases for complex 5 against MCF-7 and SW-872 cancer cells, while complex 6 could arrest the MCF-7 and SW-872 cells in G₂ and G₁ phases, respectively. All of the compounds are fluorescent which enabled us to monitor the uptake and intracellular distribution in living human cancer cells by fluorescence microscopy.

Thiosemicarbazonecopper/Halido Systems: Structure and DFT Analysis of the Magnetic Coupling

Experimental magnetic studies performed on the [{CuLX}2] system (HL = pyridine-2-carbaldehyde thiosemicarbazone, X = Cl−, Br−, I−) point to the larger electronegativity in X, the lower magnitude of the antiferromagnetic interactions. In order to confirm this and other trends observed and to dip into them, computational studies on the [{CuLX}2] (X = Cl− (1), I− (2)) compounds are here reported. The chemical and structural comparisons have been extended to the compounds obtained in acid medium. In this regard, chlorido ligands yield the [Cu(HL)Cl2]∙H2O (3) complex, whose crystal structure shows that thiosemicarbazone links as a tridentate chelate ligand to square pyramidal Cu(II) ions. On the other hand, iodido ligands provoke the formation of the [{Cu(H2L)I2}2] (4) derivative, which contains pyridine-protonated cationic H2L+ as a S-donor monodentate ligand bonded to Cu(I) ions. Crystallographic, infrared and electron paramagnetic resonance spectroscopic results are discussed. Computational calculations predict a greater stability for the chlorido species, containing both the neutral (HL) and anionic (L−) ligand. The theoretical magnetic studies considering isolated dimeric entities reproduce the sign and magnitude of the antiferromagnetism in 1, but no good agreement is found for compound 2. The sensitivity to the basis set and the presence of interdimer magnetic interactions are debated.

Synthesis, characterization, thermal properties, antimicrobial evaluation, ADMET study, and molecular docking simulation of new mono Cu (II) and Zn (II) complexes with 2-oxoindole derivatives

One of the interesting research fields is developing and assessing novel metal-containing medications. A new isatin-3-thiosemicarbazone derivative 4 was synthesized by two different methods based on hydrazone derivatives 2 and 3. Additionally, the chelation of thiosemicarbazone with copper (II) and zinc (II) forms a monobasic tridentate (ONS) complex with two five-member rings and a tetrahedral geometry structure. The structure of synthesized complexes was characterized using elemental analysis, FT-IR, mass spectra, and ¹H/¹³C NMR. Thermogravimetric analysis revealed the upgrading of the thermal stability of metal complexes compared to their thiosemicarbazone ligand. The stoichiometric ratio of the coordination confirmed the formation of 1:1 (M: L) stoichiometry. In vitro antimicrobial activity was screened against two gram-positive, two gram-negative, and one fungal strain. Both ligand 4 and Zn complex 6 displayed high antimicrobial activity compared with copper complex 5 based on the zone of inhibition. Further, MIC and MBC were determined for both zinc and ligand. The zinc complex 6 displayed excellent antimicrobial activity with (MIC = 3.9-27.77 μg/mL) against bacterial strains and (MIC = 7.81 μg/mL) against C. albicans, as well as exhibited MBC values ranging between (MBC = 6.51-45.58 μg/mL) and (MFC = 13.58 μg/mL), respectively, and demonstrated bactericidal and fungicidal behavior. The in-silico ADMET study for ligand and two complexes were determined and showed non-AMES toxicity, non-carcinogenic, and obey the rule of five. A comparative docking study provided more insight into the binding mechanisms and suggested that antimicrobial activity may be due to inhibition of different targets.

A turn-on bis-BODIPY chemosensor for copper recognition based on the in situ generation of a benzimidazole–triazole receptor and its applications in bioimaging

A bis-BODIPY-based fluorescent probe (BODIPY-NN) is developed for Cu2+ detection in aqueous solutions and living cells. The sensing mechanism is based on the in situ generation of a benzimidazole–triazole receptor induced by Cu2+ ions.

Antibacterial activity of metal complexes based on cinnamaldehyde thiosemicarbazone analogues

The development of microbial antibiotic resistance has become one of the biggest threats to global health and the search for new molecules active against resistant pathogenic strains is a challenge that must be tackled. In many cases nosocomial infections are caused by bacteria characterized by multi-drug resistance patterns and by their ability to produce biofilms. These properties lead to the persistence of pathogens in the hospital environment. This paper reports the synthesis and characterization of three thiosemicarbazone derivatives based on a compound containing the cinnamaldehyde natural scaffold but possessing different logPow values. These molecules are then used as ligands to prepare complexes of the Cu(II) and Zn(II) ions. All these compounds, ligands and complexes, were screened in vitro on stains of Escherichia coli and Klebsiella pneumoniae for their antibacterial activity. Despite their molecular similarity they revealed variegated behaviors. Only two of them present interesting antimicrobial properties and have also been studied to verify their stability in solution. The compound with the lowest partition coefficient is the most promising. The minimal bactericidal concentration on K. pneumoniae and E. coli of these substances are very interesting and demonstrate that the use of metalloantibiotics is a promising device to fight antibiotic resistance.

Trinuclear copper(ii) bromide complex [C3H5N3Br]2n[Cu3Br8]n. Structure, magnetic properties and DFT calculations

Halidocuprates(ii) show unusual magnetic properties and a high degree of structural flexibility.

Synthesis of 2-acetylpyridine-N-substituted thiosemicarbazonates of copper(ii) with high antimicrobial activity against methicillin resistant S. aureus, K. pneumoniae 1 and C. albicans

The basic interest in the present study pertains to developing metal based antimicrobial agents, as several microorganisms have built resistance to the conventional drugs.