Triphenyltin(IV) Carboxylates with Exceptionally High Cytotoxicity against Different Breast Cancer Cell Lines

Organotin(IV) carboxylates are a class of compounds explored as alternatives to platinum-containing chemotherapeutics due to propitious in vitro and in vivo results, and distinct mechanisms of action. In this study, triphenyltin(IV) derivatives of non-steroidal anti-inflammatory drugs (indomethacin (HIND) and flurbiprofen (HFBP)) are synthesized and characterized, namely [Ph3Sn(IND)] and [Ph3Sn(FBP)]. The crystal structure of [Ph3Sn(IND)] reveals penta-coordination of the central tin atom with almost perfect trigonal bipyramidal geometry with phenyl groups in the equatorial positions and two axially located oxygen atoms belonging to two distinct carboxylato (IND) ligands leading to formation of a coordination polymer with bridging carboxylato ligands. Employing MTT and CV probes, the antiproliferative effects of both organotin(IV) complexes, indomethacin, and flurbiprofen were evaluated on different breast carcinoma cells (BT-474, MDA-MB-468, MCF-7 and HCC1937). [Ph3Sn(IND)] and [Ph3Sn(FBP)], unlike the inactive ligand precursors, were found extremely active towards all examined cell lines, demonstrating IC50 concentrations in the range of 0.076–0.200 µM. Flow cytometry was employed to examine the mode of action showing that neither apoptotic nor autophagic mechanisms were triggered within the first 48 h of treatment. However, both tin(IV) complexes inhibited cell proliferation potentially related to the dramatic reduction in NO production, resulting from downregulation of nitric oxide synthase (iNOS) enzyme expression.

Copper(II) complexes with non-steroidal anti-inflammatory drugs: Structural characterization, in vitro and in silico biological profile

Six novel copper(II) complexes with the non-steroidal anti-inflammatory drugs ibuprofen, loxoprofen, fenoprofen and clonixin as ligands were synthesized and characterized by diverse techniques including single-crystal X-ray crystallography. The in vitro scavenging activity of the complexes against 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and the ability to reduce H₂O₂ were studied in the context of the antioxidant activity studies. The complexes may interact with calf-thymus DNA via intercalation as revealed by the techniques employed. The affinity of the complexes for bovine and human serum albumins was evaluated by fluorescence emission spectroscopy and the corresponding binding constants were determined. Molecular docking simulations on the crystal structure of calf-thymus DNA, human and bovine serum albumins were also employed in order to study in silico the ability of the studied compounds to bind to these target biomacromolecules, in terms of impairment of DNA and transportation through serum albumins, to explain the observed in vitro activity and to establish a possible mechanism of action.

Alkali complexes of non-steroidal anti-inflammatory drugs inhibit lung and oral cancers in vitro

Alkali metal complexes (Li, K, and Cs) displayed excellent activities against oral and lung cancer cells with the least toxicity toward normal cells.

Beyond the Simple Copper(II) Coordination Chemistry with Quinaldinate and Secondary Amines

Copper(II) acetate has reacted in methanol with quinaldinic acid (quinoline-2-carboxylic acid) to form [Cu(quin)₂(CH₃OH)]∙CH₃OH (1) (quin⁻ = an anionic form of the acid) with quinaldinates bound in a bidentate chelating manner. In the air, complex 1 gives off methanol and binds water. The conversion was monitored by IR spectroscopy. The aqua complex has shown a facile substitution chemistry with alicyclic secondary amines, pyrrolidine (pyro), and morpholine (morph). trans-[Cu(quin)₂(pyro)₂] (2) and trans-[Cu(quin)₂(morph)₂] (4) were obtained in good yields. The morpholine system has produced a by-product, trans-[Cu(en)₂(H₂O)₂](morphCOO)₂ (5) (morphCOO⁻ = morphylcarbamate), a result of the copper(II) quinaldinate reaction with ethylenediamine (en), an inherent impurity in morpholine, and the amine reaction with carbon dioxide. (pyroH)[Cu(quin)₂Cl] (3) forms on the recrystallization of [Cu(quin)₂(pyro)₂] from dichloromethane, confirming a reaction between amine and the solvent. Similarly, a homologous amine, piperidine (pipe), and dichloromethane produced (pipeH)[Cu(quin)₂Cl] (11). The piperidine system has afforded both mono- and bis-amine complexes, [Cu(quin)₂(pipe)] (6) and trans-[Cu(quin)₂(pipe)₂] (7). The latter also exists in solvated forms, [Cu(quin)₂(pipe)₂]∙CH₃CN (8) and [Cu(quin)₂(pipe)₂]∙CH₃CH₂CN (9). Interestingly, only the piperidine system has experienced a reduction of copper(II). The involvement of amine in the reduction was undoubtedly confirmed by identification of a polycyclic piperidine compound 10, 6,13-di(piperidin-1-yl)dodecahydro-2H,6H-7,14-methanodipyrido[1,2-a:1′,2′-e][1,5]diazocine.

Synthesis, crystal structures and characterizations of three new copper(II) complexes including anti-inflammatory diclofenac

Three new diclofenac-based copper(II) complexes, namely tetrakis{μ-2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O:O′}bis(methanol-κO)copper(II), [Cu2(μ-dicl)4(CH3OH)2] (1), bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1-vinyl-1H-imidazole-κN 3)copper(II), [Cu(dicl)2(vim)2] (2), and bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κ2 O,O′}bis(1H-imidazole-κN 3)copper(II), [Cu(dicl)2(im)2] (3) [dicl is diclofenac (C14H10Cl2NO2), vim is 1-vinylimidazole (C5H6N2) and im is imidazole (C3H4N2)], have been synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. X-ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn-μ2 coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)2 L 2] (L is vim or im) in which the CuII ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT–IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu2(μ-dicl)4(CH3OH)2] units was also confirmed by magnetic data to be lower than the spin-only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.

Click Chemistry-Assisted Synthesis of a β-d-Galactose-Targeted SiO2@RC Shell-Core Structure as a Nanoplatform for Metal-Based Complex Delivery

A facile reversed-phase microemulsion method was used to synthesize shell-core nanospheres of SiO₂@RCs (SiO₂-encapsuled rare-earth metal complexes). β-d-Galactose was then grafted onto the surfaces of the nanospheres through the copper(I)-catalyzed azide-alkyne cycloaddition click reaction for targeted delivery. The chemical characteristics and surface profiles of the nanocarriers were investigated by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and scanning electron microscopy. A high-efficiency microwave synthesis method was applied to prepare five complex cores by the reaction of different rare-earth metal salts with two isomeric ligands, o-CPA (2-chlorophenoxyacetic acid) and m-CPA (3-chlorophenoxyacetic acid). The crystal structures of the five synthesized RC cores were confirmed through X-ray diffraction, which revealed the formulas of five RCs, [Dy( o-CPA)₃(H₂O)]·H₂O RC₁, [Ho( o-CPA)₃(H₂O)]·H₂O RC₂, 2[Er( m-CPA)₃(H₂O)]·3H₂O RC₃, 2[Gd( m-CPA)₃(H₂O)]·3H₂O RC₄, and [Ce₂( m-CPA)₆(H₂O)₃]·2H₂O RC₅. An in vitro cell study revealed that all RCs exhibited certain anticancer activities. RC₂, in particular, showed the strongest cytotoxicity against HepG2 cells. The enhanced cell permeability and drug retention considerably improved the cytotoxicity of all SiO₂@RC₂-gal relative to that of RC₂. The selective uptake of the β-d-galactose-conjugated nanospheres by HepG2 cells through mechanisms mediated by cell surface receptors resulted in fewer side effects on extrahepatic tissues. Our contribution provides a novel design concept of a target SiO₂@RCs-gal nanocarrier for delivering affordable antitumor complexes in cancer therapy.