The unexpected formation of biologically active Cu(II) Schiff mono-base complexes with 2-thiophene-carboxaldehyde and dipropylenetriamine: crystal and molecular structure of CudptaSCl2

Theoretical and Experimental In-vitro Studies of Novel Thiophene Based Organotellurium(IV) Complexes

Schiff bases are one of the important classes of organic compounds containing imine or azomethine functional groups with potential biological applications in medicinal chemistry. Nowadays, these compounds have attracted the scientific community's attention due to their ability to act as ligands in the formation of stable metal complexes with significant biological activity. In this connection, we have designed and synthesized six novel thiophene-based organoltellurium (IV) complexes using a novel N-((5-methylthiophen-2-yl) methylene)-2-nitroaniline (5MTCONA) schiff base. These complexes underwent analytical investigation (TGA, Powder XRD, SEM, EDAX) as well as spectral analysis (FT-IR, NMR, Mass spectrometry, UV-Vis). The in-vitro pharmacological evaluation of these compounds has been carried out as antimicrobial and antioxidant agents. To further corroborate our findings, we have implemented computational analyses (Semi empirical PM3 method, Molecular Docking, and ADMET) of all the compounds with Spartan-14, Hex-8.0., Swiss ADME software. Precisely, our study integrates experimental and theoretical aspects, offering innovative insights in the field of pharmaceutical sciences.

Cu(II), Mn(II) and Zn(II) complexes of hydrazones with a quaternary ammonium moiety: synthesis, experimental and theoretical characterization and cytotoxic activity

In this paper, Cu(II), Mn(II) and Zn(II) complexes with N,N,N-trimethyl-2-oxo-2-(2-(1-(thiazol-2-yl)ethylidene)hydrazinyl)ethan-1-aminium chloride (HL1Cl) were synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and DFT calculations. In all three complexes, a ligand (L1) is coordinated in a deprotonated formally neutral zwitterionic form via NNO donor set atoms. Cu(II) and Zn(II) form mononuclear penta-coordinated complexes [CuL1(N₃)(CH₃OH)]BF₄ and [ZnL1(N₃)₂], respectively, while Mn(II) forms a binuclear [Mn₂L1₂(μ-_1,1-N₃)₂(N₃)₂]·2CH₃OH complex, with unusual distorted trigonal-prismatic geometry around the metal centers. The antimicrobial activity of these complexes was tested against a panel of Gram-negative and Gram-positive bacteria, two yeasts and one fungal strain. The binuclear Mn(II) complex showed antifungal activity of similar intensity to amphotericin B. Based on the results of the brine shrimp test and DPPH radical scavenging activity, the most active Cu(II) and Mn(II) complexes were selected for evaluation of cytotoxic activity against five malignant cancer cell lines (HeLa, A375, MCF7, PC-3 and A549) and one normal cell line HaCaT. Both complexes showed significant activity. It should be pointed out that the activity of the Mn(II) complex against the MCF7 breast cancer cell line is only slightly weaker than that of cisplatin, but with selectivity to the tumor cell line in comparison to normal HaCaT cells, which is non-existent in the case of cisplatin.

Synthesis and physicochemical, DFT, thermal and DNA-binding analysis of a new pentadentate N3S2 Schiff base ligand and its [CuN3S2]2+ complexes

A new N₃S₂ pentadentate Schiff base ligand derived from 5-bromothiophene-2-carbaldehyde, (E)-N1-((5-bromothiophen-2-yl)methylene)-N2-(2-((E)-((5-bromothiophen-2-yl)-methylene amino) ethyl ethane-1,2-diamine, is prepared. The ligand and its complexes are subjected to extensive physical and theoretical analyses and the results are consistent with their predicted compositions. Dicationic Cu(ii) complexes ([CuN₃S₂]X₂) with a coordination number of 5 are proposed on the basis of the spectral data with N₃S₂ serving as a pentadentate ligand. The prepared complexes display a square pyramidal geometry around the Cu(ii) center. TG shows different thermal behavior for the N₃S₂ ligand and its complexes. Solvatochromism of the complexes is promoted by the polarity of the solvent used. A one-electron transfer Cu(ii)/Cu(i) reversible redox reaction is promoted by CV. SEM and EDS of the free ligand and its complexes support the morphology and composition changes observed upon the complexation of Cu(ii). As an outstanding goal to develop anticancer new metal chemotherapy, preliminary studies of the binding of the desired complexes with DNA were carried out, as it is through judging the strength of interactions that a future drug can be designed and synthesized. The viscosity and absorption results obtained for complex 1 indicated its enhanced CT-DNA binding properties as compared to those of complex 2 with K_b values of 3.2 × 10⁵ and 2.5 × 10⁵ M⁻¹, respectively.

A new N₃S₂ pentadentate Schiff base ligand derived from 5-bromothiophene-2-carbaldehyde, (E)-N1-((5-bromothiophen-2-yl)methylene)-N2-(2-((E)-((5-bromothiophen-2-yl)-methylene amino) ethyl ethane-1,2-diamine, is prepared.

A new Schiff base coordinated copper(II) compound induces apoptosis and inhibits tumor growth in gastric cancer

Background

Gastric cancer, as a multifactorial disorders, shows cytological and architectural heterogeneity compared to other gastrointestinal cancers, making it therapeutically challenging. Cisplatin is generally used in clinic for gastric cancer treatment but with toxic side effects and develops resistance. Anti-tumor properties of copper and its coordinated compounds have been explored intensively in recent years.

Methods

In this study, we synthesized a novel Schiff base copper coordinated compound (SBCCC) and examined its antitumor effects in two gastric cancer cell lines SGC-7901 and BGC-823 as well as a mouse model of gastric cancer.

Results

The results show that SBCCC can significantly inhibit the proliferation of gastric cancer cells in a dose- and time-dependent manner. The IC50 of SBCCC in SGC-7901 and BGC-823 cells is 1 μM, which is much less than cisplatin’s IC50. SBCCC induces apoptosis and causes cell cycle arrest at the G1 phase. SBCCC induces apoptosis via multiple pathways including inhibition of NF-κB, ROS production and autophagy.

Conclusions

The synthesized SBCCC induced cancer cell death via inhibition of NF-κB, ROS production and autophagy. The multiple cell-killing mechanisms were important to overcome therapeutic failure because of multidrug-resistance of cancer cells. SBCCC, with a lower IC50 compared to cisplatin, could render it the potential to overcome the side-effect for clinical application.

Cu(ii) complexes of a tridentate N,N,O-donor Schiff base of pyridoxal: synthesis, X-ray structures, DNA-binding properties and catecholase activity

DNA binding and catecholase activities of two Cu(ii) complexes [Cu(L₁)X] (X = N₃, NCS) of pyridoxal derived ligands are reported.

One new azido bridged dinuclear copper(ii) thiosemicarbazide complex: synthesis, DNA/protein binding, molecular docking study and cytotoxicity activity

Biological potential of a copper(ii) complex found to exhibit in vitro antiproliferative activity towards two cell lines, AGS and A549 cancer cells.

Four copper(II) compounds synthesized by anion regulation: Structure, anticancer function and anticancer mechanism

Copper (Cu) compounds are a promising candidate for next generation metal anticancer drugs. Therefore, we regulated anions to synthesize four mononuclear and binuclear Cu(II) compounds derived from thiosemicarbazone Schiff base ligands and characterized them. Four of these compounds showed very high cytotoxicity to cancer cell lines in vitro. These Cu(II) compounds strongly promoted the apoptosis of BEL-7404 cells and had a capacity to arrest the cell cycle at S phase of those cells. Furthermore, reactive oxygen species (ROS), mitochondrial membrane potential and Western blot analyses revealed that these Cu(II) compounds exert their cytotoxicity through an ROS-mediated intrinsic mitochondrial pathway accompanied by the regulation of Bcl-2 family proteins.

A Schiff base-derived copper (II) complex is a potent inducer of apoptosis in colon cancer cells by activating the intrinsic pathway

Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II) complex on HT-29 colon cancer cells. The Cu(BrHAP)2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87  μg/ml after 72 h of treatment. HT-29 cells treated with Cu (II) complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25  μg/ml, the Cu(BrHAP)2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II) complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP)2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.

Coordination behavior of tetraaza [N₄] ligand towards Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes: synthesis, spectroscopic characterization and anticancer activity

Novel eight Co(II), Ni(II), Cu(II), Cu(I) and Pd(II) complexes with [N(4)] ligand (L) i.e. 2-amino-N-{2-[(2-aminobenzoyl)amino]ethyl}benzamide have been synthesized and structurally characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and molar conductivity measurements. On the basis of IR, mass, electronic and EPR spectral studies an octahedral geometry has been proposed for Co(II), Ni(II) complexes and Cu(II) chloride complex, square-pyramidal for Cu(I) bromide complex. For Cu(II) nitrate complex (6), Pd(II) complex (8) square planar geometry was proposed. The EPR data of Cu(II) complexes in powdered form indicate d(x2-y2) ground state of Cu(II) ion. The antitumor activity of the synthesized ligand and some selected metal complexes has been studied. The palladium(II) complex (8) was found to display cytotoxicity (IC(50)=25.6 and 41 μM) against human breast cancer cell line MCF-7 and human hepatocarcinoma HEPG2 cell line.

Structural studies and anticancer activity of a novel (N6O4) macrocyclic ligand and its Cu(II) complexes

A novel (N6O4) macrocyclic ligand (L) and its Cu(II) complexes have been prepared and characterized by elemental analysis, spectral, thermal (TG/DTG), magnetic, and conductivity measurements. Quantum chemical calculations have also been carried out at B3LYP/6-31+G(d,p) to study the structure of the ligand and one of its complexes. The results show a novel macrocyclic ligand with potential amide oxygen atom, amide and amine nitrogen atoms available for coordination. Distorted square pyramidal ([Cu(L)Cl]Cl·2.5H2O (1), [Cu(L)NO3]NO(3)·3.5H2O (2), and [Cu(L)Br]Br·3H2O (4) and octahedral ([Cu(L)(OAc)2]·5H2O (3)) geometries were proposed. The EPR data of 1, 2, and 4 indicate d1x2(-y)2 ground state of Cu(II) ion with a considerable exchange interaction. The measured cytotoxicity for L and its complexes (1, 2) against three tumor cell lines showed that coordination improves the antitumor activity of the ligand; IC50 for breast cancer cells are ≈8.5, 3, and 4 μg/mL for L and complexes (1) and (2), respectively.

Synthesis, characterization, DNA binding and cleavage studies of chiral Ru(II) salen complexes

Interaction of chiral Ru(II) salen complexes (S)-1 and (R)-1 with Calf Thymus DNA (CT-DNA) was studied by absorption spectroscopy, competitive binding study, viscosity measurements, CD measurements, thermal denaturation study and cleavage studies by agarose gel electrophoresis. The DNA binding affinity of (S)-1 (6.25 x 10(3)M(-1)) was found to be greater than (R)-1 (3.0 x 10(3)M(-1)). The antimicrobial studies of these complexes on five different gram (+)/(-) bacteria and three different fungal organisms showed selective inhibition of the growth of gram (+) bacteria and were not affective against gram (-) and fungal organisms. Further, the (S)-1 enantiomer inhibited the growth of organisms to a greater extent as compared to (R)-1 enantiomer.

In vivo anticancer, anti-inflammatory, and toxicity studies of mixed-ligand Cu(II) complexes of dien and its Schiff dibases with heterocyclic aldehydes and 2-amino-2-thiazoline. Crystal structure of [Cu(dien)(Br)(2a-2tzn)](Br)(H2O)

A new series of complexes of the type [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], where dien=diethylenetriamine and dienXX=Schiff dibase of diethylenetriamine formed with 2-furaldehyde (dienOO), 2-thiophenecarboxaldehyde (dienSS), or pyrrol-2-carboxaldehyde (dienNN); Y=Cl, Br or NO(3); and 2a-2tzn=2-amino-2-thiazoline, were synthesized and their structure established by C, H, N and Cu analysis; IR and electronic spectra; magnetic susceptibility; and molar conductivity. The isolated complexes are monomers, paramagnetic, and electrolytes of types 1:1 or 1:2. In both types of solid state complexes, [Cu(dien)(2a-2tzn)Y(2)] and [Cu(dienXX)(2a-2tzn)Y(2)], dien and its Schiff dibases are bonded to Cu(II) in a tridentate fashion through 3N atoms. The coordination sphere is completed by the endocyclic nitrogen of the thiazoline moiety and by two Cl, Br, or NO(3) groups with distorted octahedral geometry. The proposed structure of these compounds was supported by X-ray analysis of [Cu(dien)(Br)(2a-2tzn)](Br)(H(2)O). The coordination polyhedron around the copper atom can be described as a distorted square pyramid [Cu(dien)(Br)(2a-2tzn)](+). Its basal plane is occupied by the four nitrogen atoms of the dien and thiazoline ligands with Cu-N distances ranging between 1.996(6) and 2.032(3)A, and the axial position is occupied by one of the two bromine atoms (Br1) with a Cu1-Br1 bond distance of 2.782(1)A. The second bromine atom (Br2) is 4.694(2)A from the copper atom, which exists as a discrete anion and is responsible for the cationic nature of the complex. Results regarding toxicity, antitumor, and anti-inflammatory activities of the investigated compounds are promising and allow the selection of a lead compound for further biological studies.