Copper(I) halide complexes of N-methylbenzothiazole-2-thione: Synthesis, structure, luminescence, antibacterial activity and interaction with DNA

Synthesis, Characterization, and Applications of Rare-Earth-Based Complexes with Antibacterial and Antialgal Properties

The pursuit of environmentally friendly and highly effective antifouling materials for marine applications is of paramount importance. In this study, we successfully synthesized novel rare earth-based complexes by coordinating cerium (Ce III), samarium (Sm III), and europium (Eu III) with pyrithione (1-hydroxy-2-pyridinethione; PT). Extensive characterizations were performed, including single-crystal X-ray analysis, which revealed the intriguing binuclear structure of these complexes. This structural motif comprises two rare-earth ions intricately double-bridged by two oxygen atoms from the PT ligand, resulting in a distinctive and intriguing geometry. Furthermore, the central rare earth ion is surrounded by three sulfur atoms and two additional oxygen atoms, forming a unique distorted bicapped trigonal prismatic configuration. Compared with conventional antifouling biocides such as sodium pyrithione (NaPT), copper pyrithione (CuPT), and zinc pyrithione (ZnPT), these newly synthesized rare-earth complexes exhibited a remarkable boost in their in vitro antibacterial efficacy against both Gram-positive and Gram-negative bacteria. Additionally, these complexes demonstrated significant potential as antialgal agents, displaying impressive activity against marine planktonic organisms. These findings underscore the promising application prospects of these rare-earth complexes in the field of marine antifouling.

Inhibition of Cancer Cell Proliferation and Bacterial Growth by Silver(I) Complexes Bearing a CH3-Substituted Thiadiazole-Based Thioamide

Ag(I) coordination compounds have recently attracted much attention as antiproliferative and antibacterial agents against a wide range of cancer cell lines and pathogens. The bioactivity potential of these complexes depends on their structural characteristics and the nature of their ligands. Herein, we present a series of four Ag(I) coordination compounds bearing as ligands the CH₃-substituted thiadiazole-based thioamide 5-methyl-1,3,4-thiadiazole-2-thiol (mtdztH) and phosphines, i.e., [AgCl(mtdztH)(PPh₃)₂] (1), [Ag(mtdzt)(PPh₃)₃] (2), [AgCl(mtdztH)(xantphos)] (3), and [AgmtdztH)(dppe)(NO₃)]_n (4), where xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene and dppe = 1,2-bis(diphenylphosphino)ethane, and the assessment of their in vitro antibacterial and anti-cancer efficiency. Among them, diphosphine-containing compounds 3 and 4 were found to exhibit broad-spectrum antibacterial activity characteristics against both Gram-(+) and Gram-(-) bacterial strains, showing high in vitro bioactivity with IC₅₀ values as low as 4.6 μΜ. In vitro cytotoxicity studies against human ovarian, pancreatic, lung, and prostate cancer cell lines revealed the strong cytotoxic potential of 2 and 4, with IC₅₀ values in the range of 3.1-24.0 μΜ, while 3 and 4 maintained the normal fibroblast cells' viability at relatively higher levels. Assessment of these results, in combination with those obtained for analogous Ag(I) complexes bearing similar heterocyclic thioamides, suggest the pivotal role of the substituent groups of the thioamide heterocyclic ring in the antibacterial and anti-cancer efficacy of the respective Ag(I) complexes. Compounds 1-4 exhibited moderate in vitro antioxidant capacity for free radicals scavenging, as well as reasonably strong ability to interact with calf-thymus DNA, suggesting the likely implication of these properties in their bioactivity mechanisms. Complementary insights into the possible mechanism of their anti-cancer activity were provided by molecular docking calculations, exploring their ability to bind to the overexpressed fibroblast growth factor receptor 1 (FGFR1), affecting cancer cells' functionalities.

Development of a novel anti-tuberculosis nanodelivery formulation using magnesium layered hydroxide as the nanocarrier and pyrazinamide as a model drug

Designing and synthesizing biodegradable drug delivery systems are key research areas in biomedical nanotechnology. Here, we report the development of biodegradable magnesium-layered hydroxide (MgLH) based nanodelivery systems using magnesium oxide (MgO) as the precursor by a precipitation method. The designed nanocarrier does not contain any trivalent metal ions, which are most commonly used for the synthesis of layered double hydroxides (LDHs). The designed delivery system was characterized in detail using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Thermogravimetric analysis (TGA), Transmission electron microscopy (TEM) and inductively coupled plasma (ICP) analyses. The anti-tuberculosis (anti-TB) drug pyrazinamide (PZA) was successfully intercalated into interlayer galleries of MgLH, resulting in the formation of the nanocomposite, PZA-MgLH, having an average size of about 107 ± 24 nm with a uniform circular shape. The in vitro release of PZA in a human body simulated phosphate buffer saline (PBS) solution was sustained (i.e., almost 66 h) and followed a pseudo-secondorder kinetic model. Moreover, the designed nanodelivery system was found to be highly biocompatible with human normal lung cells (MRC-5) and with 3T3 fibroblast cells as controls for 24 and 48 h. Lastly, the PZA-MgLH nanocomposite showed good anti-tuberculosis activity against Mycobacterium tuberculosis and both the PZA-MgLH nanocomposite and its released free drug PZA showed antibacterial activity against tested Gram-positive and Gram-negative bacteria with percentage inhibition ranging from 5.6% to 68% against S. aureus, E. coli, and P. aeruginosa for the PZA free drug, and 32% to 32.5% against E. coli for the PZA-MgLH nanocomposite. In summary, the present results provide significant evidence that the designed nanodelivery system can be used for the delivery of PZA and, thus, should be investigated further for a wide range of anti-TB applications.

A Novel Para-Amino Salicylic Acid Magnesium Layered Hydroxide Nanocomposite Anti-Tuberculosis Drug Delivery System with Enhanced in vitro Therapeutic and Anti-Inflammatory Properties

INTRODUCTION

Mycobacterium tuberculosis infections are associated with severe local inflammatory reactions, which may be life-threatening and lead to tuberculosis pathogenesis and associated complications. Inorganic nanolayers have been vastly exploited for biomedical applications (especially in drug delivery) because of their biocompatible and biodegradable nature with the ability to release a drug in a sustained manner. Herein, we report a new nanodelivery system of inorganic nanolayers based on magnesium layered hydroxides (MgLH) and a successfully intercalated anti-tuberculosis drug para-aminosalicylic acid (PAS).

METHODS

The designed anti-tuberculosis nanodelivery composite, MgLH-PAS, was prepared by a novel co-precipitation method using MgNO3 as well MgO as starting materials.

RESULTS

The designed nano-formulation, PAS-MgLH, showed good antimycobacterial and antimicrobial activities with significant synergistic anti-inflammatory effects on the suppression of lipopolysaccharide (LPS) stimulated inflammatory mediators in RAW 264.7 macrophages. The designed nano-formulation was also found to be biocompatible with human normal lung cells (MRC-5) and 3T3 fibroblast cells. Furthermore, the in vitro release of PAS from PAS-MgLH was found to be sustained in human body simulated phosphate buffer saline (PBS) solutions of pH 7.4 and pH 4.8.

DISCUSSION

The results of the present study are highly encouraging for further in vivo studies. This new nanodelivery system, MgLH, can be exploited in the delivery of other drugs and in numerous other biomedical applications as well.

Synthesis, characterization and in vitro cytotoxicity studies of novel Cu(II) complex containing zonisamide drug: DNA interaction by multi spectroscopic and molecular docking methods

In this study, the Cu(II) complex with Zonisamide (ZNS) and 1, 10-Phenanthroline (Phen) ligands as an anticancer metallodrug was synthesized and characterized successfully by FT-IR, mass spectrometry, TGA, XPS, AAS, CHNSO, magnetic susceptibility and electrical conductivity. The interaction of Cu(II) complex with DNA was explored through a multi-spectroscopic approach such as fluorescence, UV-vis spectrophotometry, CD spectroscopy, and viscosity measurements. Molecular docking simulation was carried out to gain a deeper insight into the target site of DNA which interacted with the mentioned complex. The competitive binding tests with Hoechst 33258 showed that [CuCl₂(ZNS)(Phen)EtOH].H₂O can bind to the groove site of DNA. The calculated thermodynamic parameters, ΔS° = +201.15 J mol^-1K^-1 and ΔH° = +41.32 kJ mol^-1 confirm that the hydrophobic forces and hydrogen bonding play an essential role in the binding process. The experimental and molecular modeling results demonstrate that the Cu(II) complex binds to DNA through major groove binding. Moreover, the in vitro cytotoxic effects of [CuCl₂(ZNS)(Phen)EtOH].H₂O against B92 cancer cell lines showed better activity in Cu(II) complex in comparison to free ZNS. Therefore, [CuCl₂(ZNS)(Phen)EtOH].H₂O can open a new horizon in the treatment of glioma cancer by ZNS metallodrugs.Communicated by Ramaswamy H. Sarma.

Silver complexes with heterocyclic thioamide and tertiary arylphosphane ligands: Synthesis, crystal structures, in vitro and in silico antibacterial and cytotoxic activity, and interaction with DNA

Herein we report on the synthesis and molecular structures of six silver(I) mixed-ligand complexes containing a heterocyclic thioamide [4-phenyl-imidazole-2-thione (phimtH) or 2,2,5,5-tetramethyl-imidazolidine-4-thione (tmimdtH)] and a tertiary arylphosphane [triphenylphosphine (PPh₃), tri-o-tolylphosphane (totp)] or diphosphane [(1,2-bis(diphenylphosphano)ethane (dppe), bis(2-diphenylphosphano-phenyl)ether (DPEphos) or 4,5-bis(diphenylphosphano)-9,9-dimethylxanthene) (xantphos)]. The interaction of the compounds with calf-thymus DNA (CT DNA), as monitored directly via UV-vis spectroscopy and DNA-viscosity measurements and indirectly via its competition with ethidium bromide for DNA-intercalation sites, is suggested to take place via an intercalative mode. The new complexes show selective significant in vitro antibacterial activity against four bacterial strains. The antiproliferative effects and cytostatic efficacies of the complexes against four human cancer cell lines were evaluated. The best cytostatic and cytotoxic activity was appeared for the complexes bearing the phimtH moiety. In order to explain the described in vitro activity of the complexes, and to approach a possible mechanism of action, molecular docking studies were adopted on the crystal structure of CT DNA, DNA-gyrase, human estrogen receptor alpha and a cell-cycle specific target protein, human cyclin-dependent kinase 6.

Expanding the chemistry of ring-fused 1,4-diphosphinines by stable mono anion formation

Synthesis of a novel tricyclic 1,4-diphosphinine I and, subsequently, of a stable anionic 1,4-diphosphinine II is reported; while II can be used as precursor for 1,4-disubstitution products, its oxidation leads to the formation of the P–P coupling product III.

Synthesis, structures and antimicrobial activity of copper derivatives of N-substituted imidazolidine-2-thiones: unusual bio-activity against Staphylococcus epidermidis and Enterococcus faecalis

Synthesis and antimicrobial activity of copper(i) complexes with N-substituted imidazolidine-2-thiones is investigated.

Heteroleptic Copper(I) Complexes of "Scorpionate" Bis-pyrazolyl Carboxylate Ligand with Auxiliary Phosphine as Potential Anticancer Agents: An Insight into Cytotoxic Mode

New copper(I) complexes [CuCl(PPh3)(L)] (1: L = LA = 4-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane; (2: L = LB = 3-carboxyphenyl)bis(3,5-dimethylpyrazolyl)methane) were prepared and characterised by elemental analysis and various spectroscopic techniques such as FT-IR, NMR, UV-Vis, and ESI-MS. The molecular structures of complexes 1 and 2 were analyzed by theoretical B3LYP/DFT method. Furthermore, in vitro DNA binding studies were carried out to check the ability of complexes 1 and 2 to interact with native calf thymus DNA (CT-DNA) using absorption titration, fluorescence quenching and circular dichroism, which is indicative of more avid binding of the complex 1. Moreover, DNA mobility assay was also conducted to study the concentration-dependent cleavage pattern of pBR322 DNA by complex 1, and the role of ROS species to have a mechanistic insight on the cleavage pattern, which ascertained substantial roles by both hydrolytic and oxidative pathways. Additionally, we analyzed the potential of the interaction of complex 1 with DNA and enzyme (Topo I and II) with the aid of molecular modeling. Furthermore, cytotoxic activity of complex 1 was tested against HepG2 cancer cell lines. Thus, the potential of the complex 1 is promising though further in vivo investigations may be required before subjecting it to clinical trials.

Copper(I) halide complexes of 2,2,5,5-tetramethyl-imidazolidine-4-thione: Synthesis, structures, luminescence, thermal stability and interaction with DNA

Five neutral mononuclear copper(I) halide complexes containing 2,2,5,5-tetramethylimidazolidine-4-thione (tmimdtH) and triphenylphosphane (PPh3) or tri-o-tolylphosphane (totp) have been prepared and structurally characterized by X-ray single-crystal analysis. The complexes containing PPh3 adopt the usual distorted tetrahedral geometry, while the presence of the bulkier totp forces the formation of three-coordinated trigonal planar species. The interaction of the compounds with calf-thymus DNA was monitored directly via UV-vis spectroscopy, DNA-viscosity measurements and indirectly via its competition with ethidium bromide for DNA studied by fluorescence emission spectroscopy. Intercalation was revealed as the most possible mode of binding. Furthermore, luminescent properties and thermal stabilities of the complexes were investigated.

Crystal structure of (μ-N-allyl-thio-urea-κ(2) S:S)bis-[μ-bis-(di-phenyl-phosphanyl)methane-κ(2) P:P']bis-[bromido-copper(I)] aceto-nitrile disolvate

The reaction of cuprous bromide with a mixture of 1,1-bis-(di-phenyl-phosphan-yl)methane (dppm: C25H22P2) and N-allyl-thio-urea (ATU: C4H8N2S) in aceto-nitrile yielded the title solvated dinuclear complex, [Cu2Br2(C4H8N2S)(C25H22P2)2]·2C2H3N or [Cu2Br2(ATU)(dppm)2]·2CH3CN. Both Cu(+) ions adopt distorted tetra-hedral geometries, being coordinated by one terminal Br atom, one μ(2)-S atom of the bridging ATU ligand and two P atoms of the bridging dppm ligands. Within the complex, intra-molecular C-H⋯S, C-H⋯π, N-H⋯Br and π-π stacking inter-actions are observed. In the crystal, the components are linked by N-H⋯Br and C-H⋯N hydrogen bonds and weak π-π stacking inter-actions, generating chains propagating in the [100] direction.

Hetero-nanocomposites of magnetic and antifungal nanoparticles as a platform for magnetomechanical stress induction in Saccharomyces cerevisiae

Copper(i) oxide (Cu₂O) nanoparticles (NPs) of 30 nm with antifungal properties have been functionalized with 9 nm nickel ferrite (NiFe₂O₄) magnetic nanoparticles (MNPs) to construct hetero-nanocomposites (NCs) of a submicron hydrodynamic size for magnetomechanical stress induction in the yeast, Saccharomyces cerevisiae. A post-synthetic approach involving the assembly through hydrophobic interactions of the preformed NPs of non-uniform sizes, albeit coated with the same surfactant (oleylamine), is reported. Solvents of different polarity were implemented during the synthetic procedure resulting in NCs of similar composition consisting mainly of MNPs randomly decorated onto the bigger Cu₂O NPs. The antifungal properties of the building NPs and the NCs were studied in terms of fungistatic and fungicidal activity, whereas the ionic leaching was found to be negligible, highlighting the nanosize effect. Although S. cerevisiae cells were found to be resistant to individual NiFe₂O₄ MNPs because of their small size, their sensitivity to NCs significantly increased upon short-time exposure to a rotating low-frequency magnetic field (10 min, 30 Hz, 35 G) and this arises from the collective properties. The magnetomechanical cell stress induction was accompanied by alteration of cellular membrane integrity and programmed cell death signaling.

Silver(I) complexes of N-methylbenzothiazole-2-thione: synthesis, structures and antibacterial activity

Three silver(I) complexes containing N-methylbenzothiazole-2-thione (mbtt) have been prepared and structurally characterized by X-ray single-crystal analysis. Silver(I) nitrate, and silver(I) triflate react with mbtt to give homoleptic complexes of formula [(mbtt)2Ag(μ-mbtt)2Ag(mbtt)2](NO3)2 (1) and [Ag(mbtt)3](CF3SO3) (2) respectively, while silver(I) chloride gives the binuclear halide-bridged [(mbtt)2Ag(μ2-Cl)2Ag(mbtt)2] (3). In the binuclear complex 1 the two metal ions, separated by 3.73 Å from each other, are doubly bridged by the exocyclic S-atoms of two mbtt ligands, with the tetrahedral environment around each silver ion being completed by the S-atoms of two terminally bonded mbtt units. Compound 2 is mononuclear with the metal ion surrounded by the exocyclic S-atoms of three mbtt ligands in a nearly ideal trigonal planar arrangement. The new complexes showed significant in vitro antibacterial activity against certain Gram-positive and Gram-negative bacterial strains.

The structural and electronic impact on the photophysical and biological properties of a series of CuI and AgI complexes with triphenylphosphine and pyrimidine-type thiones

A controllable S,P-coordination environment resulting in selective structural, emissive and antibacterial properties.

Selective synthesis of Cu₂O and Cu/Cu₂O NPs: antifungal activity to yeast Saccharomyces cerevisiae and DNA interaction

A facile selective synthesis of Cu2O and heterogeneous Cu/Cu2O nanoparticles (NPs) was achieved through a solvothermal approach by Cu(NO3)2 in proportion of three different surfactants, namely, tetraethylene glycol (TEG), oleylamine (OAm) and polyoxyethylene (20) sorbitan laurate (Tween 20). Formation aspects for the spherical Cu2O@OAm (30 nm) and Cu2O@Tween (12 nm) as well as for the core-shell and semishell Cu/Cu2O@TEG NPs (7 nm) and the Cu/Cu2O@OAm (170 nm) nanorods have been proposed. The fungistatic and fungicidal activity of the newly synthesized NPs was studied in vitro against the yeast Saccharomyces cerevisiae, which constitutes a unicellular eukaryotic model microorganism in molecular and cell biology. The antifungal results, based on optical density and fluorescence measurements, clearly indicate that the composition, size, and amount of surfactant are of key importance in the antifungal properties of the NPs. Cu2O@OAm NPs exhibited the most prominent antifungal activity with 3.73 μg/mL IC(50viability) value. The isolated DNA of S. cerevisiae cells after exposure to the NPs was investigated, and binding and/or degradation phenomena were recorded that are correlated to the size and concentration of the NPs. Their activity pathway was further explored, and reactive oxygen species production and lipid peroxidation were verified mainly for Cu2O NPs.