Platinum complex with pyrimidine- and morpholine-based ligand: synthesis, spectroscopic, DFT, TDDFT, catalytic reduction, in vitro anticancer, antioxidant, antimicrobial, DNA binding and molecular modeling studies

Investigation of the ability of 3-((4-chloro-6-methyl pyrimidin-2-yl)amino) isobenzofuran-1(3H)-one to bind to double-stranded deoxyribonucleic acid

Phthalides represent a notable category of secondary metabolites that are prevalent in various plant species, certain fungi, and liverworts. The significant pharmacological properties of these compounds have led to the synthesis of a novel phthalide derivative. The current study focuses on investigating the binding interactions of a newly synthesized 3-substituted phthalide derivative, specifically 3-((4-chloro-6-methyl pyrimidine-2-yl)amino) isobenzofuran-1(3H)-one (Z11), with double-stranded deoxyribonucleic acid (dsDNA). Research in the pharmaceutical and biological fields aimed at developing more potent DNA-binding agents must take into account the mechanisms by which these newly synthesized compounds interact with DNA. This investigation seeks to explore the binding dynamics between dsDNA and our compound through a variety of analytical techniques, such as electrochemistry, UV spectroscopy, fluorescence spectroscopy, and thermal denaturation. The binding constant (Kb) of Z11 with DNA was determined using both spectroscopic and voltammetric approaches. The research revealed that Z11 employs a groove binding mechanism to associate with dsDNA. To further explore the interactions between Z11 and dsDNA, the study utilized density functional theory (DFT) calculations, molecular docking, and molecular dynamics simulations. These analyses aimed to ascertain the potential for a stable complex formation between Z11 and dsDNA. The results indicate that Z11 is situated within the minor groove of the dsDNA, demonstrating the ability to establish a stable complex. Furthermore, the findings imply that both π-alkyl interactions and hydrogen bonding play significant roles in the stabilization of this complex.

Exploring novel NH-form resorcinol-based schiff base and its metal complexes: Synthesis, characterization, cytotoxic activity, molecular docking and ADME studies

The research investigates the cytotoxic effects of the stable NH-form of a resorcinol-based Schiff base (HL) and its metal complexes (Zn(II), Cd(II), Cu(II), Ni(II)) on MCF-7 breast cancer cells. The structural characterization was conducted utilizing diverse analytical techniques, including mass spectrometry, elemental analysis, molar conductance, magnetic moment, UV-Vis, IR and ESR. The crystalline state analysis of HL through X-ray crystallography disclosed a hybrid structure comprising two canonical forms, specifically the quinoid and zwitterion, that contribute to resonance and diverse interactions, resulting in the development of a three-dimensional form. NMR, IR and ESR analyses showed that the HL was bidentate, using the oxygen of the hydroxyl and the nitrogen atom of azomethine, bonded to the metal center during complexation. The study explored the cytotoxic effects of HL and the various metal complexes on MCF-7 human breast cancer cells. All complexes display significant cytotoxicity (IC50 < 38.37 μM). The activity of the complexes was greater than that of the free ligand, with the Cu(II) complex followed by Zn(II) demonstrated superior cytotoxicity compared to Cd(II), and Ni(II) complexes. Notably, the Cu(II) and Zn(II) complex exhibited approximately 13.2 and 12.9 times greater cytotoxicity than the 5-F Uracil (5-FU) cancer drug. An MTT assay corroborated the antiproliferative activity. The molecular docking study has been performed for all compounds with the aromatase cytochrome P450 receptor protein associated with breast cancer (PDB code = 3eqm). ADME drug likeness model has been done.

Novel pyrimidines as COX-2 selective inhibitors: synthesis, DFT analysis, molecular docking and dynamic simulation studies

Pyrimidine and its derivatives are associated with varieties of biological properties. Therefore, we herein reported the synthesis of four novel pyrimidines (2, 3, and 4a, b) derivatives. The structure of these molecules is confirmed by spectroscopic methods such as IR, NMR, and Mass analysis. The electronic behavior of synthesized compounds 4a, b and in silico drug design 4 c, d was explained by Density Functional Theory estimations at the DFT/B3LYP level via 6-31 G++ (d, p) replicates the structure and geometry. All the synthesized compounds were screened for their in vitro COX-1 and COX-2 inhibitory activity compared to standards Celecoxib and Ibuprofen. Compounds 3 and 4a afforded excellent COX-1 and COX-2 inhibitory activities at IC50 = 5.50 and 5.05 μM against COX-1, 0.85 and 0.65 μM against COX-2, respectively. The standard drugs Celecoxib and Ibuprofen showed inhibitory activity at IC50 = 6.34 and 3.1 μM against COX-1, 0.56 and 1.2 μM against COX-2, respectively. Further, these compounds showed high potential docking with SARS-CoV-2 Omicron protease & COX-2 and predicted drug-likeness for the pyrimidine analogs by using Molinspiration. The protein stability, fluctuations of APO-protein, protein-ligand complexes were investigated through Molecular Dynamics simulations studies using Desmond Maestro 11.3 and potential lead molecules were identified.Communicated by Ramaswamy H. Sarma.

Preparation of a Pt(II)-3-Hydroxy-2-tolyl-4H-chromen-4-one Complex Having Antimicrobial, Anticancerous, and Radical Scavenging Activities with Related Computational Studies

A novel benzopyran-based platinum (II)-3-hydroxy-2-tolyl-4H-chromen-4-one (HToC) complex has been prepared and studied by UV-visible spectrophotometry. The study is based on the colored complexation between Pt(II) and HToC in the pH range of 8.92-9.21, resulting in the formation of a stable binary yellow complex exhibiting λmax at 509-525 nm. The formed complex maintains linearity between 0.0 and 1.8 μg Pt(II) mL-1. The well-known qualitative analytical methods, including Job's method of continuous variations and the mole ratio approach, have both proven that the stoichiometry of the complex is 1:2 [Pt(II)/HToC]. Hence, the analytical results suggest that the formed platinum complex exhibits a square planar geometry. The values of various attributes corresponding to spectrophotometric studies and statistical calculations, such as the molar extinction coefficient (6.790 × 104 L mol-1 cm-1), Sandell's sensitivity (0.0029 μg Pt(II) cm-2), standard deviation (± 0.0011), RSD (0.317%), limit of detection (0.0147 μg mL-1) and correlation coefficient (0.9999), show that the performed study satisfies all of the criteria for good sensitivity, versatility, and cost-effectiveness. In order to have an apprehension of the molecular geometry and other structural specifics of the complex, DFT studies have been carried out. The in vitro anticancer potential of the ligand and its platinum complex in the human breast cancer cell line (T-27D), as determined by the MTT assay, reveals that the complex has better antiproliferative potential than the ligand. The antimicrobial potential of the complex has been successfully tested against both Gram-positive and -negative bacteria. Antioxidant capacity results suggest the better radical scavenging capacity of the complex than that of the ligand.

An expeditious on-water regioselective synthesis of novel arylidene-hydrazinyl-thiazoles as DNA targeting agents

A series of twenty novel (E)-arylidene-hydrazinyl-thiazole derivatives has been synthesized employing α-bromo-β-diketones, thiosemicarbazide, and aromatic/heteroaromatic aldehydes with a simple and facile one-pot multicomponent reaction passageway. This organic transformation proceeds efficiently in aqueous media and demonstrated a large functional group tolerance. The structures and stereochemistry of the regioisomeric product were rigorously characterized using heteronuclear 2D NMR experiments. The binding potential of the synthesized analogs with B-DNA dodecamer d(CGCGAATTCGCG)₂ was primarily screened using molecular modeling tools and further, mechanistic investigations (either groove or intercalation) were performed using various spectroscopic techniques such as UV-Visible, Fluorescence, and Circular dichroism. The absorption spectra showed a hyperchromic shift in the absorption maxima of ctDNA with successive addition of thiazole derivatives, implying groove binding mode of interactions, further supported by displacement assay and circular dichroism analysis. Furthermore, steady-state fluorescence analysis revealed the static mode of quenching and moderate bindings between the ligand and DNA biomolecule. The competitive studies showed that the derivatives having a pyridinyl (heteroaromatic) group in their structure, bind with the nucleic acid of calf-thymus (ctDNA) more effectively in the minor groove region as compared with the aromatic substitutions.

Recent Trends in the Development of Novel Metal-Based Antineoplastic Drugs

Since the accidental discovery of the anticancer properties of cisplatin more than half a century ago, significant efforts by the broad scientific community have been and are currently being invested into the search for metal complexes with antitumor activity. Coordination compounds of transition metals such as platinum (Pt), ruthenium (Ru) and gold (Au) have proven their effectiveness as diagnostic and/or antiproliferative agents. In recent years, experimental work on the potential applications of elements including lanthanum (La) and the post-transition metal gallium (Ga) in the field of oncology has been gaining traction. The authors of the present review article aim to help the reader "catch up" with some of the latest developments in the vast subject of coordination compounds in oncology. Herewith is offered a review of the published scientific literature on anticancer coordination compounds of Pt, Ru, Au, Ga and La that has been released over the past three years with the hope readers find the following article informative and helpful.

Bio-inspired nickel nanoparticles of pyrimidine-Schiff base: In vitro anticancer, BSA and DNA interactions, molecular docking and antioxidant studies

In this work, interactions of pyrimidine derivative Schiff base ligand (DMPMM) were studied and its stabilized powder nickel nanoparticles (DMPMM-NiNPs) were synthesized and various biological studies were evaluated. DNA binding studies of CT-DNA with prepared compounds in Tris-HCl/NaCl buffer were carried out by traditional UV-Visible and fluorescence spectroscopic methods, viscosity measurements and cyclic voltammetry. Results showed that the small scale of DMPMM had less activity to interact with biological systems and when it assembled on nickel nanoparticles surface the activity increased. Thermal denaturation and sonochemical denaturation studies of DNA with the presence and the absence of our compounds also were done by UV-Visible spectroscopic method and its results indicated that the synthesized compounds increased the denaturation temperature. BSA binding studies of synthesized compounds were done by UV-Visible and fluorescence spectroscopy. Molecular docking of prepared ligand and its nanoparticles with biomolecules (DNA and BSA) were studied. Antimicrobial studies of the DMPMM and DMPMM-NiNPs were carried out by Agar-Agar well diffusion method. Anticancer studies results evidenced that the synthesized DMPMM-NiNPs had good selectivity to control the growth of cancer cells without damaging the normal cells. Various antioxidant scavenging studies results have shown that DMPMM and DMPMM-NiNPs have significant antioxidant activity. HighlightsStable and solid nickel nanoparticles were prepared.The size of the prepared nickel nanoparticles was nearly 3 to 8 nm.Organic ligand capped nickel nanoparticles interacted with DNA and BSA.Ni nanoparticles increased the denaturation temperature of DNA.It was found to have good anticancer activity with fewer side effects than cisplatin.Communicated by Ramaswamy H. Sarma.

Nd2O3, Cr2O3, and V2O3 Nanoparticles via Calcination: Synthesis, Characterization, Antimicrobial and Antioxidant Activities

Nd2O3, Cr2O3, and V2O3 nanoparticles were prepared by calcining the precursor materials that are novel mixed ligand complexes: [Nd(BDC)(ADMPY)(OAc)].H2O, [Cr(BDC)(ADM PY)Cl].H2O, and [V(BDC)(ADMPY)Cl].H2O, where BDC = 1,4-benzenedicarboxylic acid and ADMPY = 2-amino-4,6-dimethyl pyrimidine. The generated compounds were examined through several techniques such as elemental analysis (C.H.N), UV-Vis spectroscopy, thermal analysis (thermogravimetric, differential thermogravimetry, and differential thermal analysis), FT-IR spectra, X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). The TEM micrographs showed that neodymium oxide nanoparticles assumed agglomerated platelet-like particles, with particle sizes around 30.16 nm, while chromium oxide NPs showed solid block material with compact density and fewer pores with nearly spherical shape and 56.12 nm size. The vanadium oxide NPs were an agglomeration of small spherical nanoparticles of 28.4 nm size. The antimicrobial properties of the samples were assessed using two strains of Gram-positive bacteria, two strains of Gram-negative bacteria, and one strain of yeast. The antimicrobial results demonstrated that a large spectrum of activity characterizes the tested compounds because they are active on Gram-positive and Gram-negative bacteria, especially on Gram-positive strains. The antioxidant activity of prepared compounds was assessed by scavenging free radicals of DPPH. Metal oxide NPs also showed promising results as antioxidants.

Novel Self-assembly Pd(II)-Schiff Base Complex Modified Glassy Carbon Electrode for Electrochemical Detection of Paracetamol

A self-assembly Pd-Schiff base complex was synthesized and used as an electrochemical sensor in phosphate buffer solution, where it enhanced the electrocatalytic activity toward the paracetamol detection. The Schiff base {(HL) = (4-(((Z)-3-(hydroxyimino) butan-2-ylidene) amino)-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one)} was selected to prepare Pd-based complexes due to its high antimicrobial activity. A linear calibration curve was constructed using GC/Pd-SB in paracetamol concentration range of 1–50 μM and its detection limit was calculated as 0.067 μM. The modified electrode, GC/Pd-SB, could successfully determine the paracetamol concentration in human blood serum and commercial drug tablets with high sensitivity. The prepared metal complex was characterized using techniques, namely, X-ray diffraction (XRD) and scanning electron microscope (SEM). In addition, electrochemical studies were performed using different electrochemical techniques like cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). DFT calculations were used to estimate the equilibrium geometry, molecular orbital, ground-state properties, and interaction energy between paracetamol and palladium.

Graphical Abstract

Visible-Light-Prompted Synthesis and Binding Studies of 5,6-Dihydroimidazo[2,1-b]thiazoles with BSA and DNA Using Biophysical and Computational Methods

Fused heterocyclic systems containing a bridgehead nitrogen atom have emerged as imperative pharmacophores in the design and development of new drugs. Among these heterocyclic moieties, the imidazothiazole scaffold has long been used in medicinal chemistry for the treatment of various diseases. In this study, we have established a simplistic and environmentally safe regioselective protocol for the synthesis of 5,6-dihydroimidazo[2,1-b]thiazole derivatives from easily available reactants. The reaction proceeds through in situ formation of the α-bromodiketones ensuing trap with imidazolidine-2-thione to provide these versatile bicyclic heterocycles in excellent yields. The synthesized compounds were screened through the molecular docking approach for the most stable complex formation with bovine serum albumin (BSA) and calf thymus deoxyribonucleic acid (ctDNA). The selected compound was further studied using ex vivo binding studies, which revealed moderate interactions with BSA and ctDNA. The binding studies were performed using biophysical approaches including UV-visible spectroscopy, steady-state fluorescence, circular dichroism (CD), and viscosity parameters.

QSAR Modeling, Molecular Docking and Cytotoxic Evaluation for Novel Oxidovanadium(IV) Complexes as Colon Anticancer Agents

Four new drug-based oxidovanadium (IV) complexes were synthesized and characterized by various spectral techniques, including molar conductance, magnetic measurements, and thermogravimetric analysis. Moreover, optimal structures geometry for all syntheses was obtained by the Gaussian09 program via the DFT/B3LYP method and showed that all of the metal complexes adopted a square-pyramidal structure. The essential parameters, electrophilicity (ω) value and expression for the maximum charge that an electrophile molecule may accept (ΔN_max) showed the practical biological potency of [VO(CTZ)₂] 2H₂O. The complexes were also evaluated for their propensity to bind to DNA through UV–vis absorption titration. The result revealed a high binding ability of the [VO(CTZ)₂] 2H₂O complex with K_b = 1.40 × 10⁶ M⁻¹. Furthermore, molecular docking was carried out to study the behavior of the VO (II) complexes towards colon cancer cell (3IG7) protein. A quantitative structure–activity relationship (QSAR) study was also implemented for the newly synthesized compounds. The results of validation indicate that the generated QSAR model possessed a high predictive power (R² = 0.97). Within the investigated series, the [VO(CTZ)₂] 2H₂O complex showed the greatest potential the most selective compound comparing to the stander chemotherapy drug.

Cytotoxic activity and influence on acetylcholinesterase of series dinuclear platinum(II) complexes with aromatic nitrogen-containing heterocyclic bridging ligands: Insights in the mechanisms of action

Herein, the stability, lipophilicity, in vitro cytotoxicity, and influence on acetylcholinesterase of five dinuclear platinum(II) complexes with the general formula [{Pt(en)Cl}₂(μ-L)]²⁺ (L is a different aromatic nitrogen-containing heterocyclic bridging ligands pyrazine (pz, Pt1), pyridazine (pydz, Pt2), quinoxaline (qx, Pt3), phthalazine (phtz, Pt4) and quinazoline (qz, Pt5), while en is bidentate coordinated ethylenediamine) were evaluated. The most active analyzed platinum complexes induced time-dependent growth inhibition of A375, HeLa, PANC-1, and MRC-5 cells. The best efficiency was achieved on HeLa and PANC-1 cells for Pt1, Pt2, and Pt3 at the highest concentration, while Pt1 was significantly more potent than cisplatin at a lower concentration. Additionally, a lower effect on normal cells was observed compared to cisplatin, which may indicate potentially fewer side effects of these complexes. Selected complexes induce reactive oxygen species and apoptosis on tumor cell lines. The most potent reversible acetylcholinesterase (AChE) inhibitors were Pt2, Pt4, and Pt5. Pt1 showed similar inhibitory potential toward AChE as cisplatin, but a different type of inhibition, which could contribute to lower neurotoxicity. Docking studies revealed that Pt2 and Pt4 were bound to the active gorge above the catalytic triad. In contrast, the other complexes were bound to the edge of the active gorge without impeding the approach to the catalytic triad. According to this, Pt1 represents a promising compound with potent anticancer properties, high selectivity, and low neurotoxicity.

Bioactive platinum complex of ligand bearing pyrimidine skeleton: DNA/BSA binding, molecular docking, anticancer, antioxidant and antimicrobial activities

A new octahedral platinum complex [PtLCl₄] of Schiff base ligand containing pyrimidine and morpholine skeleton (where, L is 4,6-dichloropyrimidin-5-yl)methylene)-2-morpholinoethanamine) was isolated and characterized by elemental analysis, ¹H-NMR, FTIR, UV-visible and ESI-MS techniques. DNA interaction of isolated compounds with calf thymus (CT-DNA) was explored by UV-vis absorption, fluorescence, cyclic voltametric and viscometric methods. The result shows that prepared compounds can interact with CT-DNA through electrostatic interactions. Bovine serum album (BSA) binding behavior of isolated compounds was also studied by UV-vis absorption and fluorescence techniques. Both the spectroscopic results suggest that the isolated ligand and its complex bind with BSA through static quenching. The optimized structure of ligand and platinum complex were achieved by the DFT calculations. Moreover, molecular docking of ligand and its complex were studied. These analysis results reveal that ligand has low binding affinity on DNA and BSA molecules in contrast to its complex. In vitro anticancer activity of isolated compounds toward normal cell line (NHDF) as well as cancer cell lines (MCF-7, HepG2, HeLa and A549) was studied by MTT assay. The results supports that isolated platinum complex can control the growth of cancer cells (MCF-7, 20.12 ± 1.00 µg/mL; HepG2, 32.2 ± 1.69 µg/mL; HeLa, 24.68 ± 1.29 µg/mL; A549, 23.46 ± 1.17 µg/mL) without inhibiting the normal cell line (NHDF, 109.26 ± 5.46 µg/mL). Antioxidant and antimicrobial activities of isolated compounds indicate that ligand and Pt complex are found to have good radical scavenging against four different free radicals and antimicrobial abilities on E. coli and C. albicans antimicrobial species. HighlightsPlatinum complex of Schiff base with pyrimidine and morpholine linkage was synthesized.Pt complex has better biomolecular interaction with DNA and BSA.Molecular docking of Pt complex with DNA and BSA has been studiedPt complex has good anticancer activities.Pt complex has better antioxidant and antimicrobial activities.

Multispectroscopic analysis, atomic force microscopy, molecular docking and molecular dynamic simulation studies of the interaction between [SnMe2Cl2(Me2phen)] complex and ct-DNA in the presence of glucose

In this study, the spectroscopic methods (UV-vis, fluorimetric), Atomic force microscopy, and computational studies (molecular docking and molecular dynamic simulation) were used to investigate the interaction of [SnMe₂Cl₂(Me₂phen)] complex with CT-DNA in the presence of glucose. The results showed the complex in the medium containing glucose has less effect on calf thymus DNA (ct-DNA) than the medium without glucose. Cytotoxicity of [SnMe₂Cl₂(Me₂phen)] complex on MCF-7 cells was examined and showed Sn(IV) complex possesses potential cytotoxicity against this cell line. Molecular docking study showed that Sn(IV) complex interacts with DNA by groove binding mode. Radius of gyration (Rg) was smaller upon binding of the Sn(IV) complex suggesting a more compact structure of DNA in the presence of Sn(IV) complex.Communicated by Ramaswamy H. Sarma.

Cell apoptosis induced by ciprofloxacin based Cu(II) complexes: cytotoxicity, SOD mimic and antibacterial studies

The current cancer research focuses on the design and synthesis of chemical compounds that can modulate cell apoptosis or programmed cell death. So we synthesized and characterized ciprofloxacin based copper(II) complexes and studied their anticancer activity against HCT 116 cancer cells by MTT assay. We further investigated the influence of compound-2 (better IC₅₀ value than cisplatin) on cancer cells to know the exact mechanism of anticancer activity. The distinct morphological change of cells due to compound-2 was observed in bright field microscopy. The trypan blue assay clearly demonstrated inhibition of cell viability. The clonogenic ability inhibition assay showed a low percentage of the plating efficiency of HCT 116 cells. The mechanism of cell death, either apoptotic or necrotic was distinguished by annexin V-FITC/PI (propidium iodide) staining assay and LDH (lactate dehydrogenase) release assay. The positive annexinV/PI cells in presence of compound-2 and absence of LDH in the LDH release assay confirmed the cell apoptotic mechanism of cell death. We also checked in vitro antibacterial activity of compounds against Gram^(-ve) and Gram^(+ve) bacteria in terms of MIC (minimum inhibitory concentration) and the data were in good agreement with the standard drug data. SOD mimic activity of synthesized Cu(II) complexes was also studied in terms of IC₅₀ value. The brine shrimp lethality bioassay was also performed to evaluate the cytotoxic properties of the Cu(II) complexes.Communicated by Ramaswamy H. Sarma.

Recent Studies on the Antimicrobial Activity of Transition Metal Complexes of Groups 6–12

Antimicrobial resistance is an increasingly serious threat to global public health that requires innovative solutions to counteract new resistance mechanisms emerging and spreading globally in infectious pathogens. Classic organic antibiotics are rapidly exhausting the structural variations available for an effective antimicrobial drug and new compounds emerging from the industrial pharmaceutical pipeline will likely have a short-term and limited impact before the pathogens can adapt. Inorganic and organometallic complexes offer the opportunity to discover and develop new active antimicrobial agents by exploiting their wide range of three-dimensional geometries and virtually infinite design possibilities that can affect their substitution kinetics, charge, lipophilicity, biological targets and modes of action. This review describes recent studies on the antimicrobial activity of transition metal complexes of groups 6–12. It focuses on the effectiveness of the metal complexes in relation to the rich structural chemical variations of the same. The aim is to provide a short vade mecum for the readers interested in the subject that can complement other reviews.