Synthesis, structure elucidation and biological evaluation of triple bridged dinuclear copper(II) complexes as anticancer and antioxidant/anti-inflammatory agents

Design, synthesis, and evaluation of 2,2'-bipyridyl derivatives as bifunctional agents against Alzheimer's disease

Alzheimer's disease (AD) is a complex multifactorial neurodegenerative disease. Metal ion dyshomeostasis and Aβ aggregation have been proposed to contribute to AD progression. Metal ions can bind to Aβ and promote Aβ aggregation, and ultimately lead to neuronal death. Bifunctional (metal chelation and Aβ interaction) compounds are showing promise against AD. In this work, eleven new 3,3'-diamino-2,2'-bipyridine derivatives 4a-4k were synthesized, and evaluated as bifunctional agents for AD treatment. In vitro Aβ aggregation inhibition assay confirmed that most of the synthesized compounds exhibited significant self-induced Aβ1-42 aggregation inhibition. Among them, compound 4d displayed the best inhibitory potency of self-induced Aβ1-42 aggregation with IC50 value of 9.4 µM, and it could selectively chelate with Cu2+ and exhibited 66.2% inhibition of Cu2+-induced Aβ1-42 aggregation. Meanwhile, compound 4d showed strong neuroprotective activity against Aβ1-42 and Cu2+-treated Aβ1-42 induced cell damage. Moreover, compound 4d in high dose significantly reversed Aβ-induced memory impairment in mice.

New copper carboxyl-ate pyrene dimers: synthesis, crystal structure, Hirshfeld surface analysis and electrochemical characterization

Two new copper dimers, namely, bis-(dimethyl sulfoxide)-tetra-kis-(μ-pyrene-1-carboxyl-ato)dicopper(Cu-Cu), [Cu2(C17H9O2)4(C2H6OS)2] or [Cu2(pyr-COO-)4(DMSO)2] (1), and bis-(di-methyl-formamide)-tetra-kis-(μ-pyrene-1-carboxyl-ato)dicopper(Cu-Cu), [Cu2(C17H9O2)4(C3H7NO)2] or [Cu2(pyr-COO-)4(DMF)2] (2) (pyr = pyrene), were synthesized from the reaction of pyrene-1-carb-oxy-lic acid, copper(II) nitrate and tri-ethyl-amine from solvents DMSO and DMF, respectively. While 1 crystallized in the space group P , the crystal structure of 2 is in space group P21/n. The Cu atoms have octa-hedral geometries, with four oxygen atoms from carboxyl-ate pyrene ligands occupying the equatorial positions, a solvent mol-ecule coordinating at one of the axial positions, and a Cu⋯Cu contact in the opposite position. The packing in the crystal structures exhibits π-π stacking inter-actions and short contacts through the solvent mol-ecules. The Hirshfeld surfaces and two-dimensional fingerprint plots were generated for both compounds to better understand the inter-molecular inter-actions and the contribution of heteroatoms from the solvent ligands to the crystal packing. In addition, a Cu2+/Cu1+ quasi-reversible redox process was identified for compound 2 using cyclic voltammetry that accounts for a diffusion-controlled electron-donation process to the Cu dimer.

Thiol-Functionalized Cellulose-Grafted Copper Oxide Nanoparticles for the Therapy of Experimental Colitis in Swiss Albino Mice

Ulcerative colitis (UC) is a chronic inflammatory disease, which deleteriously affects the lower end of the gastrointestinal tract, i.e., the colon and the rectum. UC affects colonic inflammatory homeostasis and disrupts intestinal barrier functions. Intestinal tissue damage activates the immune system and collectively worsens the disease condition via the production of various cytokines. Ongoing therapeutics of UC have marked limitations like rapid clearance, extensive first-pass metabolism, poor drug absorption, very low solubility, bioavailability, etc. Because of these restrictions, the management of UC demands a rational approach that selectively delivers the drug at the site of action to overcome the therapeutic limiting factors. Metallic nanoparticles (NPs) have good therapeutic efficacy against colitis, but their uses are limited due to adverse effects on the biological system. In this study, we have used biocompatible thiol-functionalized cellulose-grafted copper oxide nanoparticles (C-Cu^I/IIO NPs) to treat UC. The metal NPs alleviated the colitis condition as evidenced by the colon length and observed physical parameters. Analysis of histopathology demonstrated the recovery of the colon architecture damaged by dextran sulfate sodium-induced colitis. Treatment with C-Cu^I/IIO NPs reduced the disintegration of goblet cells and the retainment of sulfomucin. Significant downregulation of inflammatory markers like MPO activity, as well as levels of nitrite and TNF-α, was found following C-Cu^I/IIO NP treatment. The observations from the study suggested that intrarectal treatment of colitis with cellulose-based C-Cu^I/IIO NPs successfully combated the intestinal inflammatory condition.

The first copper(ii) complex with 1,10-phenanthroline and salubrinal with interesting biochemical properties

The novel copper complex [Cu(phen)2(salubrinal)](ClO4)2 (C0SAL) has been synthesised and characterised. Copper(ii) is coordinated by salubrinal through the thionic group, as shown by the UV-Vis, IR, ESI-MS and tandem mass results, together with the theoretical calculations. The formed complex showed a DPPH radical scavenging ability higher than that of salubrinal alone. Studies on lipid oxidation inhibition showed that the C0SAL concentration, required to inhibit the enzyme, was lower than that of salubrinal. The inhibition of the enzyme could take place via allosteric modulation, as suggested by docking calculations. C0SAL showed a good cytotoxic activity on A2780 cells, 82 fold higher than that of the precursor salubrinal and 1.4 fold higher than that of [Cu(phen)2(H2O)](ClO4)2. Treatment with C0SAL in SKOV3 ovarian cancer cells induced expression of GRP-78 and DDIT3 regulators of ER-stress response. The cytotoxic effect of C0SAL was reverted in the presence of TUDCA, suggesting that C0SAL induces cell death through ER-stress. In A2780 cells treated with C0SAL γ-H2AX was accumulated, suggesting that DNA damage was also involved.

Synthesis, X-ray structure, antiproliferative activity, interaction with HSA and docking studies of three novel mono and binuclear copper complexes containing the maltol ligand

The present study aims at synthesizing three new copper(ii) complexes of maltol in the presence of 1,10-phenanthroline-, 2,2′-bipyridine- and 4,4-dibromo-2,2′-bipyridine ligands.

Examining barbiturate scaffold for the synthesis of new agents with biological interest

Aim: Barbiturates have a long history of being used as drugs presenting wide varieties of biological activities (antimicrobial, anti-urease and antioxidant). Reactive oxygen species are associated with inflammation implicated in cancer, atherosclerosis and autoimmune diseases. Multitarget agents represent a powerful approach to the therapy of complicated inflammatory diseases. Results: A novel series of barbiturates has been synthesized and evaluated in several in vitro assays. Compound 16b (lipoxygenases inhibitor, 55.0 μM) was found to be a cyclooxygenase-2 inhibitor (27.5 μM). Compound 8b was profiled as a drug-like candidate. Conclusion: The barbiturate core represents a new scaffold for lipoxygenases inhibition, and the undertaken derivatives show promise as multiple-target agents to combat inflammatory diseases.

Copper complex with sulfamethazine and 2,2'-bipyridine supported on mesoporous silica microspheres improves its antitumor action toward human osteosarcoma cells: cyto- and genotoxic effects

Ideal drugs to cure cancer leave normal cells unharmed while selectively turning tumor cells unviable. Several copper complexes have been able to selectively slow down tumor proliferation. We hypothesized that Cu(smz)₂(bipy)·H₂O (1)-a copper-complex that has two ligands capable of interacting with DNA-would outperform Cu(smz)₂(OH₂)·2H₂O (2), and also that supporting 1 on mesoporous silica spheres would decrease even further tumor cell viability in vitro. After exposing osteosarcoma cells (MG-63) and normal phenotype cells of bone origin (MC3T3-E1) to either complex, we studied their toxic effect and mechanisms of action. We determined cell viability (MTT assay) and quantified formation of reactive oxygen species (oxidation of DHR-123 to rhodamine). Moreover, we assessed genotoxicity from (i) formation of micronucleus (MN assay) and (ii) damage of DNA (Comet assay). After the exposure of 1 supported on silica spheres, we tested cell viability. Our results confirm our hypotheses: inhibition of tumor cells follows: supported 1 > dissolved 1 > 2. Future work that enhances the load of the complex exclusively in mesopores may improve the ability of 1 to further inhibit tumor cell viability.

Mononuclear copper(II) complexes with 2-thiophene carboxylate and N-N donors; DNA interaction, antioxidant/anti-inflammatory and antitumor activity

Redox-active compounds such as copper-phenanthroline are known as artificial/chemical nucleases with a great impact and potential for their applications as metallotherapeutics. In that vein, the mononuclear copper(II) complexes [Cu(L)₂(bipy)] (1), [Cu(L)₂(bipy)(H₂O)] (2) and [Cu(L)₂(phen)(H₂O)] (3), where L = 2-thiophene carboxylate, bipy = 2,2΄-bipyridine and phen = 1,10-phenanthroline, have been prepared and pharmacochemically studied, while the crystal structure of 1 is also reported. All the tested complexes preferably bind to CT-DNA via minor groove as resulted from UV spectroscopy studies, luminescent titration, EB competition assays and viscosity measurements. Complexes 2 and 3 in aqua behave like a "light switch" for DNA. The intensity enhancement, with the increase of DNA concentration, reached about 3-fold for 2 and 10-fold for 3. In vitro antioxidant activity of compounds 1-3, was evaluated using two different antioxidant assays: a) interaction with 1,1-diphenyl-2-picryl-hydrazyl (DPPH) stable free radical and b) inhibition of lipid peroxidation. Moreover, their inhibitory activity on soybean lipoxygenase (LOX) was evaluated for their anti-inflammatory potency. The tested complexes showed good activity on both lipid peroxidation and soybean LOX inhibition while complex 2 exhibited the best antioxidant/anti-inflammatory activity. A computational analysis over the LOX protein structure 1JNQ was performed, in an effort to support their possible mode of action. The cytotoxicity of the complexes was determined and their efficacy against several human cancer cell lines (ovarian, OAW-42; lung, A549; colon, HT29; breast, MDA-MB-231; kidney, Caki-2; and cervical, Hela) and human non-tumor cell lines (lung, MRC-5; and breast, MTSV1-7) were evaluated. The best cytotoxic activity was appeared for complex 3. In silico, computational methods support antiestrogen activity of the administered complexes on normal breast cells.