Synthesis, cytotoxicity assessment, and interaction and docking of novel palladium(II) complexes of imidazole derivatives with human serum albumin

Biological interaction of Pt complex with imidazole derivative as an anticancer compound with DNA: Experimental and theoretical studies

This investigation is applied to find out interesting information on DNA binding mode with Pt(II) derivative of two N, N bidentate ligands in treating cancer. Thus, one new water-soluble platinum complex with FIP and phen with a new formula of [Pt(phen)(FIP)](NO3)2 was prepared and specified. DFT data can be used to evaluate geometry parameters. Based on the ADMET prediction, this complex can be considered a drug-like agent. Cytotoxicity property was evaluated against some human cancerous MCF7, A549, and HCT116 cell lines. Accumulation of Pt complex, cisplatin, and oxaliplatin in each cancerous cell was determined, which is probably related to their lipophilicity and solubility properties. The binding mode of the complex to ct-DNA was investigated by fluorescence spectroscopy, circular dichroism, and molecular docking simulation. The viscosity of DNA by different concentrations of EB and Pt complex titration shows Pt complex interacts with DNA via groove binding like the spectroscopic binding result. In the MD study, DNA helix, RMSD, and RMSF analysis showed that DNA stability decreased and that the majority of residues left the initial state. DNA increased residual deviations and flexibility are linked to an increase in its gyratory radius, which is consistent with the findings of the experiments.

Spectroscopic study and molecular simulation: Bovine serum albumin binding with anticancer Pt complex of amyl dithiocarbamate ligand

Until now, many methods have been proposed to treat cancer, such as radiation therapy and drug therapy, but none of them have caused a complete cure for cancer. Heavy metal complexes such as cisplatin are among the compounds used as drugs in chemotherapy against cancer cells. These compounds cause cell death and have anti-cancer properties, but they have side effects. The biochemical mechanism of cisplatin is related to its interaction with DNA through covalent binding. To reduce the toxicity of metallodrugs, new complexes can be designed containing S, S- bidentate ligands such as diethyldithiocarbamate. Moreover, anti-cancer compounds probably interact with proteins, such as HSA, before passing the cancerous cell membrane and DNA as a target. So, the function of proteins and their stabilities are expected to change. In this research, the mode of binding of [Pt (bpy) (amyl.dtc)]NO3 complex with BSA was evaluated by various thermodynamic methods. Negative binding enthalpy and entropy changes amounts show that the connection between the Platinum compound and BSA occurs via the van Der Waals type of hydrogen bond. The negative Gibbs free energy change was obtained through isothermal titration, which showed interaction proceeds spontaneously. Moreover, the emission titration data showed that protein fluorescence quenching by platinum agent titration is static. Binding, quenching constants, and binding site number were obtained by the Stern-Volmer equation, and only one binding site was determined for this interaction. A Scatchard plot with a positive slope shows the Pt agent-BSA formation is proceeding positively cooperative. The kinetic study displayed that the absorption monitoring followed the second-order model. Finally, molecular docking simulation showed that the position of the Pt agent on protein is placed I under region II.

Molecular docking and spectroscopic study of bovine serum albumin interaction with new anticancer Pt complex with isopentyl dithiocarbamate ligand

Although cisplatin is useful in the treatment of cancer, it has a series of side effects that limit its use. Dithiocarbamates reduce the toxicity of platinum due to their structure and the presence of S, and N donating groups. In this article, the interaction of [Pt(bpy)(isopentyl.dtc)]NO3, where bpy is bipyridine and isopentyl.dtc is isopentyl-dithiocarbamate, with BSA, bovine serum albumin has been studied. The molecular binding method, including UV-Vis and fluorescence titration, was carried out in conditions including pH = 7.4 and temperatures of 27 and 37 °C. The negative values of enthalpy (ΔH°b) and entropy (ΔS°b) show that the driving forces of this interaction are hydrogen and van der Waals, and the negative value of the Gibbs free energy, ΔG°b indicates that the interaction proceeds spontaneously. The fluorescence results showed that the quenching mechanism is the static type and the Stern Volmer constant, KSV, was also obtained. The fluorescence titration method data displayed that the quenching mechanism is static. Binding constant (Kb), binding point (n), Hill coefficients, nH, Hill constant, KH, number of binding sites, g, BSA melting temperature, Tm, were also obtained. Finally, the molecular docking method result shows the binding constant, Ki and binding free energy for the platinum complex are -6.53 and 16.39 kcal mol-1, respectively, and also the proper position of binding on BSA can be considered the site I in the subdomain IIA.

Investigating the anticancer properties of the two new platinum complexes with iso- and tert-pentylglycine by the DFT, molecular docking, and ADMET assessment and experimental confirmations

In this study, two new anticancer platinum complexes formulated as [Pt(bpy)(L)]NO3 were synthesized using the iso and tert-pentylglycine ligands, two structural isomer ligands, to investigate side branches effect on the complex-DNA interaction. According to the comparative results of the ADMET assessment, these compounds can be considered as the drug-like molecules and oral medication. Mechanism of tumor inhibition and DNA binding parameters indicated the higher ability of the tert-isomer and also, both complexes acted through the disruption of the base pairs and stacks of helicity by the endothermic process. Fluorescence spectroscopy showed that the quenching mechanism is static for both drugs with large binding constant and high binding affinity towards the DNA. Also, the amount of binding constant of the tert -isomer was about 14 times of another structural isomerous complex. CD spectra indicated the conversion of the B-DNA into A-DNA form via electrostatic interaction for positively charged complexes. The cytotoxic data showed that both compounds have antiproliferative effects against the MCF-7 cell line and the inhibitory effect of the iso-derivative was better than the tert-one. Docking studies showed that the desolvation energy and hydrogen bond are more effective between the other interactions. The torsional free energy for both complexes mainly provided the groove binding along with partially electrostatic and intercalate binding. According to the density-functional theory data and because of positive electron density on the surface of complexes and facilitating of the metal drug to DNA phosphate groups approaching, both complexes may be good candidates for the anticancer drugs. Two new anticancer Pt(II) complexes were synthesized with glycine derivatives. In vitro cytotoxicity effects were tested against the human breast cancer cell line of MCF-7. Moreover, the modes of DNA binding with synthesized compounds were investigated using ADME prediction, DFT, molecular docking and spectroscopic methods.

Synthesis, characterization and antibacterial applications of pyrazolyl-sulfonamides and their palladium complexes

Pyrazolylsulphonamides compounds and their palladium complexes exhibiting good potential anti-bacterial activities.

Novel Biocompatible Amino Acids-Functionalized Three-dimensional Graphene Foams: As the Attractive and Promising Cisplatin Carriers for Sustained Release Goals

Application of amino acids-immobilized porous materials for drug delivery studies has been attracted a lot of attention in the recent years. In this study, amino acids-grafted graphene foams were prepared by anchoring of Alanine (Ala), Cysteine (Cys) and Glycine (Gly) amino acids on the surface of graphene oxide (GO) nanostructures and used as the novel biocompatible carriers to control releasing of the cisplatin as the cytotoxic anticancer drug. The characterization of prepared compounds was done by the FT-IR, Raman, TGA, N₂ adsorption-desorption isotherms, SEM, and TEM techniques. Adsorption and in vitro release behavior of amino acids-functionalized foams were studied using ICP standard method. The results show that the drug loading amount and the drug releasing rate are significantly enhanced upon functionalization process. The Ala-Foam sample with the larger surface area and pore volume showed a higher loading content (4.53%) than other samples. In addition, the MTT test on the two MCF-7 and HepG2 human cancer cell lines exhibited an acceptable biocompatibility and sustainable drug releasing from the carriers up to 48 h, leading to the dosage frequency decrease and the patient compliance improvement.

Antibacterial activities and DNA-cleavage properties of novel fluorescent imidazo-phenanthroline derivatives

Design and biological activities of fluorescent imidazo-phenanthroline derivatives; (E)-5-((4-((4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenoxy)methyl)benzylidene)amino)- isophthalicacid, 2 and 2-(4-(((5-chloroquinolin-8-yl)oxy)methyl)phenyl)-1H-imidazo[4,5f] [1,10]phenanthroline, 3, have been reported. Their characterizations were performed by spectroscopic techniques. Their promising photophysical behaviours were observed in absorbance and fluorescence studies. The antibacterial activities of the compounds were determined against seven different microorganisms; Bacillus subtilis ATCC 6633(G + ), Pseudomonas aeruginosa ATCC 29853(G-), Escherichia coli ATCC 35,218 (G-), Enterococcus faecalis ATCC 292,112 (G + ), Salmonella typhimurium ST-10 (G-), Streptococcus mutans NCTC 10,449 (G + ), and Staphylococcus aureus ATCC 25923(G + ). MIC values of 3 was determined as 156,25 μM on all tested bacteria. A preliminary study of the structure-activity relationship (SAR) also revealed that the antimicrobial activity depended on the substituents on the phenyl ring. The electron withdrawing Cl-substitued compound 3 most favour for antimicrobial activity even at lowest concentration compared to other compounds. DNA-cleavage activities of the compounds were also investigated. The interactions of the compounds with supercoiled pBR322 plasmid DNA were obtained by agarose gel electrophoresis. All imidazo-phenanthroline derivatives were found to be highly effective on DNA, even at the lowest concentrations because of their planar nature which provides ease of bind to the helix structure of DNA.

Kinetic and Thermodynamic Investigation of Human Serum Albumin Interaction with Anticancer Glycine Derivative of Platinum Complex by Using Spectroscopic Methods and Molecular Docking

In this paper, a new anticancer Pt (II) complex, cis-[Pt (NH₃)₂(tertpentylgly)]NO₃, was synthesized with glycine-derivative ligand and characterized. Cytotoxicity of this water-soluble Pt complex was studied against human cancer breast cell line of MCF-7. The interaction of human serum albumin (HSA) with Pt complex was studied by using UV-Vis, fluorescence spectroscopy methods, and molecular docking at 27 and 37 °C in the physiological situation (I = 10 mM, pH = 7.4). The negative [Formula: see text] and positive [Formula: see text] indicated that electrostatic force may be a major mode in the binding between Pt complex and HSA. Binding constant values were obtained through UV-Vis and fluorescence spectroscopy that reveal strong interaction. The negative Gibbs free energy that was obtained by using the UV-Vis method offers spontaneous interaction. Fluorescence quenching the intensity of HSA by adding Pt complex confirms the static mode of interaction is effective for this binding process. Hill coefficients, n_H, Hill constant, k_H, complex aggregation number around HSA, <J>, number of binding sites, g, HSA melting temperature, T_m, and Stern-Volmer constant, k_SV, were also obtained. The kinetics of the interaction was studied, which showed a second-order kinetic. The results of molecular docking demonstrate the position of binding of Pt complex on HSA is the site I in the subdomain IIA.

Some new anticancer platinum complexes of dithiocarbamate derivatives against human colorectal and pancreatic cell lines

Cisplatin, carboplatin and oxaliplatin and their analogs are effective anticancer agents, but their clinical using is limited by some serious side effects. S,S donor ligands such as dithiocarbamates can be used to reduce some side effects. In this study, some novel water soluble complexes with formula of [Pt(bpy)(R.dtc)]NO₃, where bpy is bipyridine and R.dtc is amyl-, isopentyl- or tertamyl-dtc (n-pentyl-, 3-metyl-butyl- and 2-methylbutan-dithiocarbamate, respectively) have been synthesized and characterized by elemental analysis, conductivity measurements and chemical analysis. The cytotoxic activities of synthesized complexes were investigated against human adenocarcinoma colorectal cell line (HT29) and human pancreatic cell line (Panc1), and compared with cisplatin and oxaliplatin, which display more anticancer activity for [Pt(bpy)(isopentyl.dtc)]NO₃. The experimental fluorescence and circular dichroism results illustrated partially groove binding of [Pt(bpy)(amyl.dtc)]NO₃ and [Pt(bpy)isopentyl.dtc)]NO₃ on DNA, while [Pt(bpy)(tertamyl.dtc)]NO₃ complex, can bind to DNA via intercalation. Finally, molecular docking simulation data of DNA interaction with three synthesized complexes showed [Pt(bpy)(amyl.dtc)]NO₃ complex has the highest tendency and negative docking energy in structural change of DNA.Communicated by Ramaswamy H. Sarma.

Polymyxins interaction to the human serum albumin: A thermodynamic and computational study

Polymyxin B and E (colistin), are a group of cationic charged cyclic antibiotic lipopeptides that are frequently used in the clinics to treat infections caused by the multidrug-resistant gram-negative bacteria. Since the interactions with the blood plasma drug-transport proteins may play a critical role in determining their pharmacological and pharmacokinetic profiles, we studied the binding properties of polymyxins to the human serum albumin (HSA) under simulated physiological conditions by the combination of biophysical approaches, such as isothermal titration calorimetry (ITC), fluorescence anisotropy, circular dichroism (CD) buttressed by computational studies. The HSA binding to the polymyxins was relatively strong (K_a ≈ 1.0 × 10⁷ M^-1). Molecular docking indicated that polymyxins bind to the cleft of HSA between domains I and III via the electrostatic interactions. This evidence was further confirmed by the entropy-driven interaction for the polymyxins bound HSA. Far UV-CD experiments showed that the secondary structure of HSA doesn't alter and its stable structure is preserved. Collectively, these investigations revealed that the polymyxins bind preferentially to the partially unfolded intermediate forms of the protein structure; however, HSA molecule does not undergo any significant conformational changes upon binding. This is promising as it may limit the unfavorable side effects of the medicine. On the whole, the results provide quantitative and qualitative insight of the binding interaction between HSA and polymyxins, which is important in understanding their effect as therapeutic agents.

Inhibitory effects of oxali-Platin as a chemotherapeutic drug on the function and structure of bovine liver catalase

Communicated by Ramaswamy H. Sarma.

Insights into the binding mechanism of BODIPY-based photosensitizers to human serum albumin: A combined experimental and computational study

Photodynamic therapy (PDT) is a noninvasive and effective approach in clinical cancer treatments. Boron-dipyrromethene (BODIPY)-based derivatives have emerged as novel and promising photosensitizers (PSs) in PDT, attributed to their strong near-infrared singlet oxygen luminescence emissions and high photostabilities. However, the binding mechanism of BODIPY derivatives to proteins, key for their therapeutic and biomedical applications is still poorly understood. Here, we investigated the molecular interactions of two 2, 6-diiodo-BODIPY derivatives with human serum albumin (HSA) using combined experimental and computational techniques. Our spectroscopic results showed that both BODIPY derivatives formed stable complexes with HSA. Strikingly, the BODIPY/HSA complexes exhibited notably enhanced water solubility and singlet oxygen generation efficiency with respect to the BODIPY alone. Furthermore, molecular docking, molecular dynamics simulations, and binding free energy calculations provided the structural and energetic insights into the binding mechanism of BODIPY-based derivatives to HSA. Our work demonstrated that conjugation of BODIPYs with HSA may be a promising strategy to enhance the performance of BODIPY-based PSs, and the combination of computational and experimental techniques is expected to play key roles in the design and development of novel PSs with improved bioavailability and biocompatibility for cancer therapeutic applications.

Biological effect and molecular docking of anticancer palladium and platinum complexes with morpholine dithiocarbamate on human serum albumin as a blood carrier protein

The aim of this study was to examine the interaction of [Pd(2,2'-bipyridine) (morpholinedithiocarbamate)]NO₃ and [Pt (2,2'-bipyridine)(morpholinedithiocarbamate)]NO₃ with human serum albumin under physiological conditions by using fluorescence, absorption, and circular dichroism spectroscopic techniques. Spectroscopic analysis of the emission quenching at different temperatures demonstrated that the quenching mechanism was static quenching. From the circular dichroism results, thermal stability study, it was found that the interaction of the complexes with human serum albumin caused a conformational change of the protein reversibly. These 2 anticancer Pd and Pt complexes were activated against chronic myelogenous leukemia cell line K562, so that 50% cytotoxic concentration values of 16 and 26 μM for Pd and Pt complexes, respectively, were observed, which were much lower than that of cisplatin (154 μM). Biological activities of both Pd and Pt complexes were also assayed against selective microorganisms by the disc diffusion method. These results showed that the Pd(II) complex is antifungal agent but Pt(II) complex has antibacterial activity. Also, the interaction of both metal derivative complexes was studied by molecular docking. Complementary molecular docking results may be useful to determine the binding mechanism of human serum albumin in pharmaceutical and biophysical studies providing new insight in the novel pharmacology.

Photodegradation of 2,4-dichlorophenol by supported Pd(X2) catalyst (X = Cl, Br, N3): a HOMO manipulating point of view

Three different palladium(II) complexes with ligands containing nitrogenized aromatic rings were investigated theoretically as model to obtain the computational band gap energies. The results demonstrated promising possibility for designing palladium(II) complexes with photocatalytic properties at visible light irradiation. Deliberated products were synthesized via grafting on the silica-coated Fe₃O₄ magnetic nanoparticles (Fe₃O₄@SiO₂). Formation of complexes on the surface of Fe₃O₄@SiO₂, as insoluble and reusable photocatalysts, was proved by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric (TGA), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), transmission electron microscope (TEM), and scanning electron microscopy (SEM) analyses. The trend of the band gap energies of prepared structures was calculated via experimental and theoretical methods. The photocatalytic capability of these nanoparticles was investigated in degradation of 2,4-dichlorophenol by means of HPLC analysis. A tentative reaction mechanism for the formation of intermediates was proposed. Graphical abstract ᅟ.

Binding forces between a novel Schiff base palladium(II) complex and two carrier proteins: human serum albumi and β-lactoglobulin

Ligand binding studies on carrier proteins are crucial in determining the pharmacological properties of drug candidates. Here, a new palladium(II) complex was synthesized and characterized. The in vitro binding studies of this complex with two carrier proteins, human serum albumin (HSA), and β-lactoglobulin (βLG) were investigated by employing biophysical techniques as well as computational modeling. The experimental results showed that the Pd(II) complex interacted with two carrier proteins with moderate binding affinity (K_b ≈ .5 × 10⁴ M^-1 for HSA and .2 × 10³ M^-1 for βLG). Binding of Pd(II) complex to HSA and βLG caused strong fluorescence quenching of both proteins through static quenching mechanism. In two studied systems hydrogen bonds and van der Waals forces were the major stabilizing forces in the drug-protein complex formation. UV-Visible and FT-IR measurements indicated that the binding of above complex to HSA and βLG may induce conformational and micro-environmental changes of two proteins. Protein-ligand docking analysis confirmed that the Pd(II) complex binds to residues located in the subdomain IIA of HSA and site A of βLG. All these experimental and computational results suggest that βLG and HSA might act as carrier protein for Pd(II) complex to deliver it to the target molecules.