Blood levels of homocysteine, cysteine, glutathione, folic acid, and vitamin B12 in the acute phase of atherothrombotic stroke

C-Geranylated flavanone diplacone enhances in vitro antiproliferative and anti-inflammatory effects in its copper(II) complexes

Two copper(II) complexes containing diplacone (H4dipl), a naturally occurring C-geranylated flavanone derivative, in combination with bathophenanthroline (bphen) or 1,10-phenanthroline (phen) with the composition [Cu3(bphen)3(Hdipl)2]⋅2H2O (1) and {[Cu(phen)(H2dipl)2]⋅1.25H2O}n (2) were prepared and characterized. As compared to diplacone, the complexes enhanced in vitro cytotoxicity against A2780 and A2780R human ovarian cancer cells (IC50 ≈ 0.4-1.2 μM), human lung carcinoma (A549, with IC50 ≈ 2 μM) and osteosarcoma (HOS, with IC50 ≈ 3 μM). Cellular effects of the complexes in A2780 cells were studied using flow cytometry, covering studies concerning cell-cycle arrest, induction of cell death and autophagy and induction of intracellular ROS/superoxide production. These results uncovered a possible mechanism of action characterized by the G2/M cell cycle arrest. The studies on human endothelial cells revealed that complexes 1 and 2, as well as their parental compound diplacone, do possess anti-inflammatory activity in terms of NF-κB inhibition. As for the effects on PPARα and/or PPARγ, complex 2 reduced the expression of leukocyte adhesion molecules VCAM-1 and E-selectin suggesting its dual anti-inflammatory capacity. A wide variety of Cu-containing coordination species and free diplacone ligand were proved by mass spectrometry studies in water-containing media, which might be responsible for multimodal effect of the complexes.

Organic cocatalysts improved Fenton and Fenton-like processes for water pollution control: A review

In recent times, organic compounds have been extensively utilized to mitigate the limitations associated with Fe(Ⅲ) reduction and the narrow pH range in Fenton and Fenton-like processes, which have garnered considerable attention in relevant studies. This review presents the latest advancements in the comprehensive analysis and applications of organic agents as assistant/cocatalysts during Fenton/Fenton-like reactions for water pollution control. The primary focus includes the following: Firstly, the mechanism of organic co-catalytic reactions is introduced, encompassing both complexation and reduction aspects. Secondly, these organic compounds are classified into distinct categories based on their functional group structures and applications, namely polycarboxylates, aminopolycarboxylic acids, quinones, phenolic acids, humic substances, and sulfhydryl compounds, and their co-catalytic functions and mechanisms of each category are discussed in meticulous detail. Thirdly, a comprehensive comparison is conducted among various types of organic cocatalysts, considering their relative merits, cost implications, toxicity, and other pertinent factors. Finally, the review concludes by addressing the universal challenges and development prospects associated with organic co-catalytic systems. The overarching objective of this review is to provide insights into potential avenues for the future advancement of organic co-catalytic Fenton/Fenton-like reactions in the context of water purification.

Mitochondria Play Essential Roles in Intracellular Protection against Oxidative Stress-Which Molecules among the ROS Generated in the Mitochondria Can Escape the Mitochondria and Contribute to Signal Activation in Cytosol?

Questions about which reactive oxygen species (ROS) or reactive nitrogen species (RNS) can escape from the mitochondria and activate signals must be addressed. In this study, two parameters, the calculated dipole moment (debye, D) and permeability coefficient (Pm) (cm s-1), are listed for hydrogen peroxide (H2O2), hydroxyl radical (•OH), superoxide (O2•-), hydroperoxyl radical (HO2•), nitric oxide (•NO), nitrogen dioxide (•NO2), peroxynitrite (ONOO-), and peroxynitrous acid (ONOOH) in comparison to those for water (H2O). O2•- is generated from the mitochondrial electron transport chain (ETC), and several other ROS and RNS can be generated subsequently. The candidates which pass through the mitochondrial membrane include ROS with a small number of dipoles, i.e., H2O2, HO2•, ONOOH, •OH, and •NO. The results show that the dipole moment of •NO2 is 0.35 D, indicating permeability; however, •NO2 can be eliminated quickly. The dipole moments of •OH (1.67 D) and ONOOH (1.77 D) indicate that they might be permeable. This study also suggests that the mitochondria play a central role in protecting against further oxidative stress in cells. The amounts, the long half-life, the diffusion distance, the Pm, the one-electron reduction potential, the pKa, and the rate constants for the reaction with ascorbate and glutathione are listed for various ROS/RNS, •OH, singlet oxygen (1O2), H2O2, O2•-, HO2•, •NO, •NO2, ONOO-, and ONOOH, and compared with those for H2O and oxygen (O2). Molecules with negative electrical charges cannot directly diffuse through the phospholipid bilayer of the mitochondrial membranes. Short-lived molecules, such as •OH, would be difficult to contribute to intracellular signaling. Finally, HO2• and ONOOH were selected as candidates for the ROS/RNS that pass through the mitochondrial membrane.

Amino acid promoted oxidation of atrazine by Fe3O4/persulfate

In the present study, we demonstrated that the presence of cysteine could remarkably enhance the degradation of atrazine by Fe3O4/persulfate system. The results of electron paramagnetic resonance (EPR) spectra confirmed the combination of cysteine and Fe3O4 exhibited much higher activity on activation of persulfate to generate more SO4•- and •OH than Fe3O4 alone. At pH of 3.0, SO4•- and •OH contributed to about 58.2 % and 41.8 % of atrazine removal respectively, while •OH gradually dominated the oxidation of atrazine from neutral condition to alkaline condition. The co-existing Cl- and HCO3- could quench SO4•-, resulting in the inhibition of atrazine degradation. The presence of low natural organic matters (NOM) concentration (0-2 mg L-1) could enhance the atrazine removal, and high concentration (>5 mg L-1) of NOM restrained the atrazine degradation. During the Cysteine/Fe3O4/Persulfate process, cysteine served as a complexing reagent and reductant. Through acidolysis and complexation, Fe3O4 could release dissolved and surface bound Fe2+, both of which contributed to the activation of persulfate together. Meanwhile, cysteine was not rapidly consumed due to a regeneration process, which was beneficial for maintaining Fe2+/Fe3+ cycle and constantly accelerating the activation of persulfate for atrazine degradation. The reused Fe3O4 and cysteine in the Cysteine/Fe3O4/Persulfate process exhibited high stability for the atrazine degradation after three cycles. The degradation pathway of atrazine included alkylic-oxidation, dealkylation, dechlorination-hydroxylation processes. The present study indicates the novel Cysteine/Fe3O4/Persulfate process might be a high potential for treatment of organic polluted water.

Anticancer Potential of Diruthenium Complexes with Bridging Hydrocarbyl Ligands from Bioactive Alkynols

Diruthenacyclopentenone complexes of the general composition [Ru2Cp2(CO)2{μ-η1:η3-CH═C(C(OH)(R))C(═O)}] (2a-c; Cp = η5-C5H5) were synthesized in 94-96% yields from the reactions of [Ru2Cp2(CO)2{μ-η1:η3-C(Ph)═C(Ph)C(═O)}] (1) with 1-ethynylcyclopentanol, 17α-ethynylestradiol, and 17-ethynyltestosterone, respectively, in toluene at reflux. Protonation of 2a-c by HBF4 afforded the corresponding allenyl derivatives [Ru2Cp2(CO)3{μ-η1:η2-CH═C═R}]BF4 (3a-c) in 85-93% yields. All products were thoroughly characterized by elemental analysis, mass spectrometry, and IR, UV-vis, and nuclear magnetic resonance spectroscopy. Additionally, 2a and 3a were investigated by cyclic voltammetry, and the single-crystal diffraction method was employed to establish the X-ray structures of 2b and 3a. The cytotoxicity in vitro of 2b and 3a-c was evaluated against nine human cancer cell lines (A2780, A2780R, MCF-7, HOS, A549, PANC-1, Caco-2, PC-3, and HeLa), while the selectivity was assessed on normal human lung fibroblast (MRC-5). Overall, complexes exert stronger cytotoxicity than cisplatin, and 3b (comprising 17α-estradiol derived ligand) emerged as the best-performing complex. Inductively coupled plasma mass spectrometry cellular uptake studies in A2780 cells revealed a higher level of internalization for 3b and 3c compared to 2b, 3a, and the reference compound RAPTA-C. Experiments conducted on A2780 cells demonstrated a noteworthy impact of 3a and 3b on the cell cycle, leading to the majority of the cells being arrested in the G0/G1 phase. Moreover, 3a moderately induced apoptosis and oxidative stress, while 3b triggered autophagy and mitochondrial membrane potential depletion.

Fe3+-cysteine enhanced persulfate fenton-like process for quinclorac degradation: A wide pH tolerance and reaction mechanism

A green, high-efficiency, and wide pH tolerance water remediation process has been urgently acquired for the increasingly exacerbating contaminated water. In this study, a Fe³⁺/persulfate (Fe³⁺/PS) system was employed and enhanced with a green natural ligand cysteine (Cys) for the degradation of quinclorac (QNC). The introduction of Cys into the Fe³⁺/PS system widened the effective pH range to 9 with a superior removal rate for QNC. The mechanism revealed that the Fe³⁺/Cys/PS system can enhance the ability of degrading QNC by accelerating the Fe³⁺/Fe²⁺ redox cycle, maintaining Fe²⁺ concentration and thereby generating more HO^• and SO₄^•-. The impact factors (i.e., pH, concentrations of PS, Fe³⁺ and Cys) were optimized as well. This work provides a promising strategy with high catalytic activity and wide pH tolerance for organic contaminated water remediation.

Homocysteine and the Mortality of Critically Ill Patients: A Meta-Analysis

Prevalence of hyperhomocysteinemia (HHcy) is high in critically ill patients. However, the association between serum homocysteine level and outcomes of the critically ill patients remains unknown. We performed a meta-analysis of cohort studies to comprehensively evaluate the above association. Relevant cohort studies were identified by search of electronic databases including PubMed, Embase, Web of Science, Wanfang, and CNKI from the inception of the databases to February 5, 2022. A randomized-effect model incorporating the possible between-study heterogeneity was used to pool the results. Overall, 16 cohorts with 1663 critically ill patients who were admitted to the intensive care unit (ICU) were involved in the meta-analysis. Pooled results showed that compared to non-survivors of the critical illnesses, survivors had significantly lower serum level of Hcy at ICU admission [mean difference (MD): -3.42 μmol/l, 95% confidence interval (CI): -5.89 to 0.94, p=0.007; I2=86%]. Subgroup analysis showed that the difference of Hcy between survivors and non-survivors was significant in Asian patients (MD: -8.17 μmol/l, p<0.001), but not in non-Asians (MD: 0.30 μmol/l, p=0.62; p for subgroup difference<0.001). Moreover, meta-analysis with seven cohorts, all including Chinese patients, showed that HHcy at ICU admission was independently associated with a higher risk of all-cause mortality in critically ill patients (odds ratio: 2.99, 95% CI: 2.26 to 3.97, p<0.001; I2=69%). A higher serum level of Hcy at ICU admission may be associated with an increased risk of all-cause mortality in critically ill patients, particularly in the Chinese population.

The Impact of Genetic Polymorphisms in Glutamate-Cysteine Ligase, a Key Enzyme of Glutathione Biosynthesis, on Ischemic Stroke Risk and Brain Infarct Size

The purpose of this pilot study was to explore whether polymorphisms in genes encoding the catalytic (GCLC) and modifier (GCLM) subunits of glutamate-cysteine ligase, a rate-limiting enzyme in glutathione synthesis, play a role in the development of ischemic stroke (IS) and the extent of brain damage. A total of 1288 unrelated Russians, including 600 IS patients and 688 age- and sex-matched healthy subjects, were enrolled for the study. Nine common single nucleotide polymorphisms (SNPs) of the GCLC and GCLM genes were genotyped using the MassArray-4 system. SNP rs2301022 of GCLM was strongly associated with a decreased risk of ischemic stroke regardless of sex and age (OR = 0.39, 95%CI 0.24−0.62, p < 0.0001). Two common haplotypes of GCLM possessed protective effects against ischemic stroke risk (p < 0.01), but exclusively in nonsmoker patients. Infarct size was increased by polymorphisms rs636933 and rs761142 of GCLC. The mbmdr method enabled identifying epistatic interactions of GCLC and GCLM gene polymorphisms with known IS susceptibility genes that, along with environmental risk factors, jointly contribute to the disease risk and brain infarct size. Understanding the impact of genes and environmental factors on glutathione metabolism will allow the development of effective strategies for the treatment of ischemic stroke and disease prevention.

Distinct roles of pH and organic ligands in the dissolution of goethite by cysteine

Electron shuttles such cysteine play an important role in Fe cycle and its availability in soils, while the roles of pH and organic ligands in this process are poorly understood. Herein, the reductive dissolution process of goethite by cysteine were explored in the presence of organic ligands. Our results showed that cysteine exhibited a strong reactivity towards goethite - a typical iron minerals in paddy soils with a rate constant ranging from 0.01 to 0.1 hr^-1. However, a large portion of Fe(II) appeared to be "structural species" retained on the surface. The decline of pH was favorable to generate more Fe(II) ions and enhancing tendency of Fe(II) release to solution. The decline of generation of Fe(II) by increasing pH was likely to be caused by a lower redox potential and the nature of cysteine pH-dependent adsorption towards goethite. Interestingly, the co-existence of oxalate and citrate ligands also enhanced the rate constant of Fe(II) release from 0.09 to 0.15 hr^-1; nevertheless, they negligibly affected the overall generation of Fe(II) in opposition to the pH effect. Further spectroscopic evidence demonstrated that two molecules of cysteine could form disulfide bonds (S-S) to generate cystine through oxidative dehydration, and subsequently, inducing electron transfer from cysteine to the structural Fe(III) on goethite; meanwhile, those organic ligands act as Fe(II) "strippers". The findings of this work provide new insights into the understanding of the different roles of pH and organic ligands on the generation and release of Fe induced by electron shuttles in soils.

A novel l-cysteine sensor using in-situ electropolymerization of l-cysteine: Potential to simple and selective detection

This work presents an all-in-one origami paper-based electrochemical platform for simple and inexpensive l-cysteine (Cys) detection using Cys as a monomer for modifying electrode surfaces. The proposed method combines the steps of electropolymerization and detection into a single device to offer a highly convenient method for the end-user. In comparison, the sensitivity toward Cys detection is a significantly increased using this modified electrode. The developed device provided a linear concentration range of 10-800 μM with a limit of detection of 5.5 μM. For application, the device was successfully applied to detect Cys in different food products such as wheat flour, bread, and cake with satisfactory results, yielding excellent intra-day and inter-day relative standard deviations (1.5-4.9%) and recoveries (84.2-110.8%). This discovery is important from the viewpoint of the development of Cys detection in other applications in the future.

Identification of potent anticancer copper(ii) complexes containing tripodal bis[2-ethyl-di(3,5-dialkyl-1H-pyrazol-1-yl)]amine moiety

A series of heteroleptic copper(ii) complexes of the composition [Cu(L^1-5)Cl]X, where X = ClO₄ and/or PF₆ and [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl))-(6-methyl-(2-pyridylmethyl))]amine (L¹), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl))-(3,4-dimethoxy-(2-pyridylmethyl))]amine (L²), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl)-(2-quinolymethyl)]amine (L³), [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazolyl)-(di(3,5-dimethyl-1H-pyrazol-1-yl-methyl))]amine (L⁴) and [bis(2-ethyl-di(3,5-dimethyl-1H-pyrazol-1-yl)-(5-methyl-3-phenyl-1H-pyrazol-1-yl-methyl)]amine (L⁵), were prepared and thoroughly characterized including single-crystal X-ray diffraction technique. The in vitro cytotoxicity of complexes against A2780, A2780R, HOS and MCF-7 human cancer cell lines was evaluated using the MTT test. The results revealed that complexes [Cu(L¹)Cl]PF₆ (1-PF₆), [Cu(L²)Cl]ClO₄ (2-ClO₄) and [Cu(L³)Cl]PF₆ (3-PF₆) are the most effective, with IC₅₀ values ranging from 1.4 to 6.3 μM, thus exceeding the cytotoxic potential of metallodrug cisplatin (IC₅₀ values ranging from 29.9 to 82.0 μM). The complexes [Cu(L⁴)Cl]PF₆ (4-PF₆) and [Cu(L⁵)Cl]PF₆ (5-PF₆) showed only moderate cytotoxicity against A2780, with IC₅₀ = 53.6 μM, and 33.8 μM, respectively. The cell cycle profile, time-resolved cellular uptake, interactions with small sulfur-containing biomolecules (cysteine and glutathione), intracellular ROS production, induction of apoptosis and activation of caspases 3/7 were also evaluated in the case of the selected complexes. It has been found that the best performing complexes 1 and 2 cause cell arrest in the G2/M phase and induce apoptosis via the increase in production of ROS, dominantly due to the overproduction of superoxide.

Baicalin and Geniposide Inhibit Polarization and Inflammatory Injury of OGD/R-Treated Microglia by Suppressing the 5-LOX/LTB4 Pathway

Cerebral ischemia causes severe neurological disorders and neuronal dysfunction. Baicalin (BC), geniposide (GP), and their combination (BC/GP) have been shown to inhibit post-ischemic inflammatory injury by inhibiting the 5-LOX/CysLTs pathway. The aims of this study were to observe the inhibitory effects of BC/GP on the activation of microglial cells induced by oxygen glucose deprivation and reoxygenation (OGD/R) and to investigate whether the 5-LOX/LTB4 pathway was involved in these effects. Molecular docking showed that BC and GP exhibited considerable binding activity with LTB4 synthase LTA4H. BV-2 microglia were transfected with a 5-LOX overexpression lentiviral vector, and then OGD/R was performed. The effects of different concentrations of BC, GP, and BC/GP (6.25 μM, 12.5 μM, and 25 μM) on cell viability and apoptosis of microglia were evaluated by MTT and flow cytometry. The expression of TNF-α, IL-1β, NF-κB, and pNF-κB also was measured by ELISA, Western blots and immunofluorescence. Western blots and qRT-PCR analysis were used to determine the levels of CD11b, CD206, and 5-LOX pathway proteins. Results showed that BC, GP, and BC/GP reduced the apoptosis caused by OGD/R in a dose-dependent manner, and cell viability was significantly increased at a concentration of 12.5 μM. OGD/R significantly increased the release of TNF-α, IL-1β, NF-κB, pNF-κB, and CD11b. These effects were suppressed by BC, GP, and BC/GP, and the OGD/R-induced transfer of NF-κB p65 from the ctytoplasm to the nucleus was inhibited in microglia. Interestingly, the LTB4 inhibitor, U75302, exhibited the same effect. Also, BC, GP, and BC/GP significantly reduced the expression of 5-LOX pathway proteins. These results demonstrated that BC/GP inhibited OGD/R-induced polarization in BV2 microglia by regulating the 5-LOX/LTB4 signaling pathways and attenuating the inflammatory response. Our results supported the theoretical basis for additional in-depth study of the function of BC/GP and the value of determining its unique target, which might provide a new therapeutic strategy for ischemic cerebrovascular disease.

A vinyl sulfone clicked carbon dot-engineered microfluidic paper-based analytical device for fluorometric determination of biothiols

A microfluidic paper-based analytical device integrating carbon dot (CDs) is fabricated and used for a fluorometric off-on assay of biothiols. Vinyl sulfone (VS) click immobilization of carbon dots (CDs) on paper was accomplished by a one-pot simplified protocol that uses divinyl sulfone (DVS) as a homobifunctional reagent. This reagent mediated both the click oxa-Michael addition to the hydroxyl groups of cellulose and ulterior covalent grafting of the resulting VS paper to NH₂-functionalized CDs by means of click aza-Michael addition. The resulting cellulose nanocomposite was used to engineer an inexpensive and robust microfluidic paper-based analytical device (μPAD) that is used for a reaction-based off-on fluorometric assay of biothiols (GSH, Cys, and Hcy). The intrinsic blue fluorescence of CDs (with excitation/emission maxima at 365/450 nm) is turned off via the heavy atom effect of an introduced iodo group. Fluorescence is turned on again due to the displacement of iodine by reaction with a biothiol. The increase in fluorescence is related to the concentration over a wide range (1 to 200 μM for GSH and 5-200 μM for Cys and Hcy, respectively), and the assay exhibits a low detection limit (0.3 μM for GSH and Cys and 0.4 μM for Hcy). The method allows for rapid screening and can also be used in combination with a digital camera readout. Graphical abstract Schematic representation of a μPAD based on click immobilized carbon dots and used for a reaction-based fluorometric off-on assay of biothiols. The intrinsic blue fluorescence of carbon dots is turned off via the heavy atom effect of an introduced iodo group and turned on by the displacement of this atom by reaction with a biothiol.

Early and Sustained Increases in Leukotriene B4 Levels Are Associated with Poor Clinical Outcome in Ischemic Stroke Patients

Leukotriene B4 (LTB4) has been implicated in ischemic stroke pathology. We examined the prognostic significance of LTB4 levels in patients with acute middle cerebral artery (MCA) infarction and their mechanisms in rat stroke models. In ischemic stroke patients with middle cerebral artery infarction, plasma LTB4 levels were found to increase rapidly, roughly doubling within 24 h when compared to initial post-stroke levels. Further analyses indicate that poor functional recovery is associated with early and more sustained increase in LTB4 rather than the peak levels. Results from studies using a rat embolic stroke model showed increased 5-lipoxygenase (5-LOX) expression in the ipsilateral infarcted cortex compared with sham control or respective contralateral regions at 24 h post-stroke with a concomitant increase in LTB4 levels. In addition, neutrophil influx was also observed in the infarcted cortex. Double immunostaining indicated that neutrophils express 5-LOX and leukotriene A4 hydrolase (LTA4H), highlighting the pivotal contributions of neutrophils as a source of LTB4. Importantly, rise in plasma LTB4 levels corresponded with an increase in LTB4 amount in the infarcted cortex, thereby supporting the use of plasma as a surrogate for brain LTB4 levels. Pre-stroke LTB4 loading increased brain infarct volume in tMCAO rats. Conversely, administration of the 5-LOX-activating protein (FLAP) inhibitor BAY-X1005 or B-leukotriene receptor (BLTR) antagonist LY255283 decreased the infarct volume by a similar extent. To conclude, targeted interruption of the LTB4 pathway might be a viable treatment strategy for acute ischemic stroke.

Mass spectrometry-based urinary metabolomics for the investigation on the mechanism of action of Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves against ischemic stroke in rats

ETHNOPHARMACOLOGICAL RELEVANCE

As a traditional Chinese medicine, Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. leaves (ESL) can treat ischemic, neurasthenia, and hypertension diseases. However, only few studies have been conducted on the mechanism of action of ESL for ischemic disease treatment.

AIM OF THE STUDY

This study aimed to discover the potential biomarkers in the rats caused by ischemic stroke and build a gene-enzyme-biomarker network to explore the mechanism of ESL treatment on ischemic stroke further.

MATERIALS AND METHODS

The urinary metabolomics strategy was developed by combining UPLC-Q-TOF/MS with multivariate data analysis. The gene-enzyme-biomarker network was built by Cytoscape 3.6.0 on the basis of the potential biomarkers filtered out via urinary metabolomic analysis. Then, the potential target enzymes of ESL in the treatment of ischemic stroke were selected for further validation analysis via the ELISA kits.

RESULTS

A total of 42 biomarkers associated with ischemic stroke have been identified, among which 38 species can be adjusted by ESL, including 5'-methylthioadenosine, prostaglandin A2, l-methionine, aldosterone, 11b-hydroxyprogesterone, prostaglandin E3, dehydroepiandrosterone, taurine, 5-methoxyindoleacetate, and p-cresol glucuronide. These biomarkers were involved in several metabolic pathways, including taurine and hypotaurine, arachidonic acid, cysteine and methionine, steroid hormone biosynthesis, tryptophan, and tyrosine metabolism pathways. The gene-enzyme-biomarker network was built, and three predicted target proteins, including cyclooxygenase-2 (COX-2), monoamine oxidase (MAO), and nitric oxide synthase (NOS), were selected as the potential target enzymes for ESL in ischemic stroke treatment.

CONCLUSIONS

All results showed that ESL can play a therapeutic role in treating ischemic stroke through different pathways. This study will provide an overall view of the mechanism underlying the action of ESL against ischemic stroke.

Half-Sandwich Ru(II) and Os(II) Bathophenanthroline Complexes Containing a Releasable Dichloroacetato Ligand

We report on the preparation and thorough characterization of cytotoxic half-sandwich complexes [Ru(η⁶-pcym)(bphen)(dca)]PF₆ (Ru-dca) and [Os(η⁶-pcym)(bphen)(dca)]PF₆ (Os-dca) containing dichloroacetate(1-) (dca) as the releasable O-donor ligand bearing its own cytotoxicity; pcym = 1-methyl-4-(propan-2-yl)benzene (p-cymene), bphen = 4,7-diphenyl-1,10-phenanthroline (bathophenanthroline). Complexes Ru-dca and Os-dca hydrolyzed in the water-containing media, which led to the dca ligand release (supported by ¹H NMR and electrospray ionization mass spectra). Mass spectrometry studies revealed that complexes Ru-dca and Os-dca do not interact covalently with the model proteins cytochrome c and lysozyme. Both complexes exhibited slightly higher in vitro cytotoxicity (IC50 = 3.5 μM for Ru-dca, and 2.6 μM for Os-dca) against the A2780 human ovarian carcinoma cells than cisplatin (IC50 = 5.9 μM), while their toxicity on the healthy human hepatocytes was found to be IC50 = 19.1 μM for Ru-dca and IC50 = 19.7 μM for Os-dca. Despite comparable cytotoxicity of complexes Ru-dca and Os-dca, both the complexes modified the cell cycle, mitochondrial membrane potential, and mitochondrial cytochrome c release by a different way, as revealed by flow cytometry experiments. The obtained results point out the different mechanisms of action between the complexes.

Improvement of amperometric transducer selectivity using nanosized phenylenediamine films

In this work, we studied the conditions of deposition of a semipermeable polyphenylenediamine (PPD)-based membrane on amperometric disk platinum electrodes. Restricting an access of interfering substances to the electrode surface, the membrane prevents their impact on the sensor operation. Two methods of membrane deposition by electropolymerization were compared-at varying potential (cyclic voltammetry) and at constant potential. The cyclic voltammetry was shown to be easier in performing and providing better properties of the membrane. The dependence of PPD membrane effectiveness on the number of cyclic voltammograms and phenylenediamine concentration was analyzed. It was shown that the impact of interfering substances (ascorbic acid, dopamine, cysteine, uric acid) on sensor operation could be completely avoided using three cyclic voltammograms in 30 mM phenylenediamine. On the other hand, when working with diluted samples, i.e., at lower concentrations of electroactive substances, it is reasonable to decrease the phenylenediamine concentration to 5 mM, which would result in a higher sensitivity of transducers to hydrogen peroxide due to a thinner PPD layer. The PPD membrane was tested during continuous operation and at 8-day storage and turned out to be efficient in sensor and biosensors.

Serum trace elements are associated with hemostasis, lipid spectrum and inflammatory markers in men suffering from acute ischemic stroke

The primary objective of the study is investigation of the association between trace elements status and hemostasis, lipid spectrum and inflammatory markers in acute ischemic stroke (AIS). A total of 30 men suffering from AIS and 30 healthy controls were involved in the current survey. Blood count, serum lipid spectrum, complement components C4 and C3a, vascular endothelial growth factor (VEGF), S100B protein, NR2 antibodies (NR2Ab), and total antioxidant status (TAS), as well as plasma fibrinogen, and D-dimer levels and activated partial thromboplastin time (APTT) were assessed. Serum trace elements were analyzed using inductively coupled plasma mass spectrometry. AIS patients were characterized by significantly increased fibrinogen, D-dimer, TG, C3a, C4, NR2Ab, and VEGF levels. The leukocyte count, erythrocyte sedimentation rate and serum atherogenic index were also increased in stroke patients. Oppositely, TAS and APTT values, bleeding and blood coagulation time were decreased. AIS patients were characterized by significantly decreased serum Fe and Co concentrations, whereas the level of Cu, I, Li, Mn, Se, Zn, As, Pb, Ni, and especially V and B in serum was significantly increased. Serum V and B tightly correlated with the procoagulant state and inflammatory markers. Multiple regression analysis revealed a significant inverse association between serum Se levels and stroke markers after adjustment for covariates. Therefore, it is hypothesized that elements like vanadium and boron may be closely involved in stroke pathogenesis by modulation of hemostasis and inflammation, whereas the observed increase in Se levels may be considered as a compensatory reaction.

In Vitro Antitumor Active Gold(I) Triphenylphosphane Complexes Containing 7-Azaindoles

A series of gold(I) complexes of the general composition [Au(naza)(PPh₃)] (1–8) was prepared and thoroughly characterized (e.g., electrospray ionization (ESI) mass spectrometry and multinuclear nuclear magnetic resonance (NMR) spectroscopy). The N1-deprotonated anions of 7-azaindole or its derivatives (naza) are coordinated to the metal centre through the N1 atom of their pyrrole ring, as proved by a single crystal X-ray analysis of the complexes [Au(3I5Braza)(PPh₃)] (7) and [Au(2Me4Claza)(PPh₃)]·½H₂O (8′). The in vitro cytotoxicity of the complexes 1–8 was studied against both the cisplatin-sensitive and -resistant variants of the A2780 human ovarian carcinoma cell line, as well as against the MRC-5 human normal fibroblast cell line. The complexes 4, 5, and 8, containing deprotonated 3-iodo-7-azaindole, 5-bromo-7-azaindole, and 2-methyl-4-chloro-7-azaindole (2Me4Claza), respectively, showed significantly higher potency (IC₅₀ = 2.8–3.5 µM) than cisplatin (IC₅₀ = 20.3 µM) against the A2780 cells and markedly lower effect towards the MRC-5 non-cancerous cells (IC₅₀ = 26.0–29.2 µM), as compared with the mentioned A2780 cancer cells. The results of the flow cytometric studies of the A2780 cell cycle perturbations revealed a G₂-cell cycle phase arrest of the cells treated by the representative complexes 1 and 5, which is indicative of a different mechanism of action from cisplatin (induced S-cell cycle phase arrest). The stability of the representative complex 8 in the water-containing solution as well as its ability to interact with the reduced glutathione, cysteine and bovine serum albumin was also studied using ¹H and ³¹P-NMR spectroscopy (studied in the 50% DMF-d₇/50% D₂O mixture) and ESI+ mass spectrometry (studied in the 50% DMF/50% H₂O mixture); DMF = dimethylformamide. The obtained results are indicative for the release of the N-donor azaindole-based ligand in the presence of the used biomolecules.

Strongly enhanced Fenton degradation of organic pollutants by cysteine: An aliphatic amino acid accelerator outweighs hydroquinone analogues

Quinone-hydroquinone analogues have been proven to be efficient promoters of Fenton reactions by accelerating the Fe(III)/Fe(II) redox cycle along with self-destruction. However, so far there is little information on non-quinone-hydroquinone cocatalyst for Fenton reactions. This study found that cysteine, a common aliphatic amino acid, can strongly enhance Fenton degradation of organic pollutants by accelerating Fe(III)/Fe(II) redox cycle, as quinone-hydroquinone analogues do. Further, cysteine is superior to quinone-hydroquinone analogues in catalytic activity, H₂O₂ utilization and atmospheric limits. The cocatalysis mechanism based on the cycle of cysteine/cystine was proposed.

Cysteine determination via adsorptive stripping voltammetry using a bare glassy carbon electrode

The electrochemical determination of cysteine is investigated by adsorptive stripping voltammetric detection of a copper-cysteine complex compound using a bare glassy carbon electrode. In acidic 0.1 M KNO3 solution (pH 4), the electrochemical oxidation of this complex compound generates a characteristic anodic peak ca. -0.17 V vs. a standard mercury/mercurous sulphate reference electrode. The voltammetric response is highly reproducible within 2.1% error (n = 3). A linear dynamic range is obtained for a cysteine concentration of 1.0 μM to 10.0 μM. The sensitivity of 0.18 ± 0.006 μA μM(-1) and the limit of detection of 0.03 μM (n = 3) make our methodology highly applicable for practical applications. Successful determination of cysteine concentration in the presence of glutathione has also been demonstrated by the sequential determination of the concentrations of total thiol and the tripeptide alone.

Correlation between secondary thrombosis in epileptic patients and serum levels of folate and vitamin B12

Epilepsy is a chronic brain dysfunction syndrome and nervous system disease whose pathogenesis remains to be determined. The aim of the present study was to analyze the correlation between secondary thrombosis and the serum levels of folate and vitamin B12 in epileptic patients, as well as to determine whether the supplementation of folate and vitamin B12 was associated with a decreased incidence of thrombosis, and provide the basis for novel clinical treatment. A total of 37 patients, diagnosed as epileptic with secondary thrombosis between April 2012 and April 2014, were included in the treatment group. A total of 37 epileptic patients without secondary thrombosis were included in the control group. The serum levels of homocysteine, folate and vitamin B12 in the two groups and in the epileptic patients with intracranial thrombosis or peripheral thrombosis were compared. According to the Guidance of Epilepsy, the patients in the two groups were administered antiepileptic drugs (AEDs) with the supplementation of folate tablet (0.4 mg/day) and vitamin B12 tablet (100 µg/day). These indicators and the incidence of thrombosis in the two groups were compared after 1 year. The serum levels of homocysteine in the two groups were higher than normal, and the levels in the treatment group were significantly higher than those in the control group. The serum levels of folate and vitamin B12 in the treatment group were significantly higher than those in the control group and the difference was statistically significant (P<0.05). The Pearson correlation analysis revealed that the serum levels of folate and vitamin B12 were not associated with the serum level of homocysteine (P>0.05). The logistic regression analysis revealed that the serum levels of folate and vitamin B12 were independent risk factors for epilepsy with secondary thrombosis [folate: odds ratio (OR)=0.635, P=0.038; vitamin B12: OR=0.418, P=0.042]. The differences in the serum levels of homocysteine, folate and vitamin B12 in the epileptic patients with intracranial thrombosis or peripheral thrombosis were not statistically significant (P>0.05). The serum levels of homocysteine in the two groups, were significantly decreased, while the levels of folate and vitamin B12 were significantly increased. The differences in the serum levels of homocysteine, folate and vitamin B12 in the two groups were not statistically significant (P>0.05). The differences in the incidence of thrombosis in the two groups were not statistically significant (P>0.05). In conclusion, the serum levels of folate and vitamin B12 were independent of serum homocysteine, and were the dependent risk factors for primary epilepsy with secondary thrombosis. The supplementation of folate and vitamin B12 may be beneficial for the prevention of epilepsy with secondary thrombosis, making it valuable in application.

Effects of antiepileptic drugs on the serum folate and vitamin B12 in various epileptic patients

Epilepsy is a common neurodegenerative disease with an increasing morbidity. Clinical treatment of epilepsy includes symptomatic treatment, etiological treatment, surgery and prevention. The aim of the present study was to determine the effects of antiepileptic drugs (AEDs) on serum folate and vitamin B12 in various epileptic patients, and to examine the correlation between these effects and secondary cerebrovascular events. A total of 68 epileptic patients, diagnosed between May 2012 and May 2014, were included in the present study. The study included 8 cases of autonomic seizures, 10 cases of absence seizures, 13 cases of complex partial seizures, 28 cases of generalized tonic-clonic seizures, and 9 cases of simple partial seizures. The patients received appropriate AED treatment according to the characteristics of epileptic seizure and the treatment guidance. The differences in the serum levels of folate and vitamin B12 in these patients, and the differences in the secondary cerebrovascular events in these patients after 1 year follow-up were analyzed. The difference in the AEDs used by various epileptic patients was statistically significant (P<0.05). The proportion of AED monotherapy in the autonomic seizure group and petit mal group was highest, and the proportion of two AED in combination with the psychomotor seizure, grand mal and simple partial seizure groups was highest. The serum levels of folate and vitamin B12 in these patients following treatment were significantly lower than those prior to treatment (P<0.05). The differences in the serum levels of folate and vitamin B12 in these groups following treatment were not statistically significant (P>0.05). The difference in the incidence of cerebrovascular events in these groups at follow up was not statistically significant (P>0.05). The multifactorial logistic regression analysis revealed that the serum levels of folate and vitamin B12 were the independent risk factors for epilepsy with secondary cerebrovascular events [folate: odds ratio (OR)=0.536, P=0.039; vitamin: OR=0.382, P=0.041]. In conclusion, various AEDs may decrease the serum levels of folate and vitamin B12 and affect the secondary cerebrovascular events in various epileptic patients. Thus, regular supplementation of folate and vitamin B12 may be an option.

Design and characterization of highly in vitro antitumor active ternary copper(II) complexes containing 2'-hydroxychalcone ligands

A series of innovative copper(II) complexes of the general composition [Cu(L_n)(phen)]NO₃ (1-8; phen=1,10-phenanthroline), involving 2'-hydroxychalcone {(E)-1-(2'-hydroxyphenyl)-3-phenylprop-2-en-1-one} derivatives (HL_n) was synthesized, thoroughly characterized and screened for in vitro cytotoxicity against a panel of ten human cancer cell lines. The most promising results were achieved for complex 2 with the best IC₅₀ value of 1.1±0.7μM (against A2780 cell line). The toxicity testing on a primary culture of human hepatocytes (HH) revealed that complex 2 is the least toxic from the whole series with the IC₅₀ value of 63.7μM. The complexes were shown to be able to efficaciously cleave pUC19 plasmid DNA as well as intercalate into calf thymus DNA with the same affinity and efficacy as ethidium bromide and interact by the ligand exchange mechanism with l-cysteine at physiological concentration levels.

Dynamic protein coronas revealed as a modulator of silver nanoparticle sulphidation in vitro

Proteins adsorbing at nanoparticles have been proposed as critical toxicity mediators and are included in ongoing efforts to develop predictive tools for safety assessment. Strongly attached proteins can be isolated, identified and correlated to changes in nanoparticle state, cellular association or toxicity. Weakly attached, rapidly exchanging proteins are also present at nanoparticles, but are difficult to isolate and have hardly been examined. Here we study rapidly exchanging proteins and show for the first time that they have a strong modulatory effect on the biotransformation of silver nanoparticles. Released silver ions, known for their role in particle toxicity, are found to be trapped as silver sulphide nanocrystals within the protein corona at silver nanoparticles in serum-containing cell culture media. The strongly attached corona acts as a site for sulphidation, while the weakly attached proteins reduce nanocrystal formation in a serum-concentration-dependent manner. Sulphidation results in decreased toxicity of Ag NPs.

The biomolecule layer adsorbed at the nanoparticle surface and defined as protein corona affects the nanoparticle biophysical properties and functions. Here, the authors suggest that rapidly-exchanging proteins on the outermost layer of the corona modulate sulphidation of silver nanoparticles in vitro.

Copper(ii) quinolinonato-7-carboxamido complexes as potent antitumor agents with broad spectra and selective effects

[Cu(qui^x)(phen)]NO₃·yH₂O (qui^x = 2-(4-amino-3,5-dichlorophenyl)-3-hydroxy-4(1H)-quinolinone-7-carboxamides) showed potent cytotoxicity against human cancer cells, lower toxicity on non-malignant cells, and ability to interact with biomolecules.

Highly and Broad-Spectrum In Vitro Antitumor Active cis-Dichloridoplatinum(II) Complexes with 7-Azaindoles

The cis-[PtCl₂(naza)₂] complexes (1–3) containing monosubstituted 7-azaindole halogeno-derivatives (naza), showed significantly higher activity than cisplatin towards ovarian carcinoma A2780, its cisplatin-resistant variant A2780R, osteosarcoma HOS, breast carcinoma MCF7 and cervix carcinoma HeLa cell lines, with the IC₅₀ values of 3.8, 3.5, 4.5, 2.7, and 9.2 μM, respectively, obtained for the most active complex 3. As for 4 and 5 having disubstituted 7-azaindoles in their molecule, the significant cytotoxicity was detected only for 4 against A2780 (IC₅₀ = 4.8 μM), A2780R (IC₅₀ = 3.8 μM) and HOS (IC₅₀ = 4.3 μM), while 5 was evaluated as having only moderate antiproliferative effect against the mentioned cancer cell lines with IC₅₀ = 33.4, 24.7 and 46.7 μM, respectively. All the studied complexes 1–5 effectively avoided the acquired resistance of ovarian carcinoma cell line. On the other hand, the complexes did not reveal any inhibition activity on the purified 20S proteasome from the A2780 cells. The representative complexes 3 and 5 showed low ability to be hydrolysed, but their stability was markedly lowered in the presence of physiological sulphur-containing biomolecule glutathione (GSH), as proved by the ¹H NMR spectroscopy and mass spectrometry studies. A rate of interaction of the studied complexes with GSH was affected by an addition of another mechanistically relevant biomolecule guanosine monophosphate. The differences in interactions of 3 and 5 with GSH correlate well with their different cytotoxicity profiles.

Synthesis, characterization and in vitro cytotoxicity of gold(iii) dialkyl/diaryldithiocarbamato complexes

A series of six dialkyl/diaryldithiocarbamato (dtc) gold(iii) complexes [Au(R₂dtc)₂]Cl (1,3, and5), and [Au(R₂dtc)Cl₂] (2,4, and6), (R = methyl, ethyl, and benzyl) was synthesised and evaluated for anticancer activity with promising results (EC₅₀≈ 9.5 μM).

Gold(I) complexes of 9-deazahypoxanthine as selective antitumor and anti-inflammatory agents

The gold(I) mixed-ligand complexes involving O-substituted derivatives of 9-deazahypoxanthine (HL_n) and triphenylphosphine (PPh₃) with the general formula [Au(L_n)(PPh₃)] (1–5) were prepared and thoroughly characterized by elemental analysis, FT-IR and multinuclear NMR spectroscopy, ESI+ mass spectrometry, single crystal X-ray (HL₅ and complex 2) and TG/DTA analyses. Complexes 1–5 were evaluated for their in vitro antitumor activity against nine human cancer lines, i.e. MCF7 (breast carcinoma), HOS (osteosarcoma), A549 (adenocarcinoma), G361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) and THP-1 (monocytic leukaemia), for their in vitro anti-inflammatory activity using a model of LPS-activated macrophages, and for their in vivo antiedematous activity by λ-carrageenan-induced hind paw edema model on rats. The results showed that the complexes 1–5 exhibit selective in vitro cytotoxicity against MCF7, HOS, 22Rv1, A2780 and A2780R, with submicromolar IC₅₀ values for 2 against the MCF7 (0.6 µM) and HOS (0.9 µM). The results of in vitro cytotoxicity screening on primary culture of human hepatocytes (HEP220) revealed up to 30-times lower toxicity of compounds against healthy cells as compared with cancer cells. Additionally, the complexes 1–5 significantly influence the secretion and expression of pro-inflammatory cytokines TNF-α and IL-1β by a similar manner as a commercially used anti-arthritic drug Auranofin. The tested complexes also significantly influence the rate and overall volume of the edema, caused by the intraplantar application of λ-carrageenan polysaccharide to rats. Based on these promising results, the presented compounds could qualify to become feasible candidates for advanced testing as potential antitumor and anti-inflammatory drug-like compounds.

Gold(I)-triphenylphosphine complexes with hypoxanthine-derived ligands: in vitro evaluations of anticancer and anti-inflammatory activities

A series of gold(I) complexes involving triphenylphosphine (PPh₃) and one N-donor ligand derived from deprotonated mono- or disubstituted hypoxanthine (HL_n) of the general composition [Au(L_n)(PPh₃)] (1–9) is reported. The complexes were thoroughly characterized, including multinuclear high resolution NMR spectroscopy as well as single crystal X-ray analysis (for complexes 1 and 3). The complexes were screened for their invitro cytotoxicity against human cancer cell lines MCF7 (breast carcinoma), HOS (osteosarcoma) and THP-1 (monocytic leukaemia), which identified the complexes 4–6 as the most promising representatives, who antiproliferative activity was further tested against A549 (lung adenocarcinoma), G-361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) cell lines. Complexes 4–6 showed a significantly higher invitro anticancer effect against the employed cancer cells, except for G-361, as compared with the commercially used anticancer drug cisplatin, with IC₅₀ ≈ 1–30 µM. Anti-inflammatory activity was evaluated invitro by the assessment of the ability of the complexes to modulate secretion of the pro-inflammatory cytokines, i.e. tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in the lipopolysaccharide-activated macrophage-like THP-1 cell model. The results of this study identified the complexes as auspicious anti-inflammatory agents with similar or better activity as compared with the clinically applied gold-based antiarthritic drug Auranofin. In an effort to explore the possible mechanisms responsible for the biological effect, the products of interactions of selected complexes with sulfur-containing biomolecules (L-cysteine and reduced glutathione) were studied by means of the mass-spectrometry study.

Bioorthogonal cyclization-mediated in situ self-assembly of small-molecule probes for imaging caspase activity in vivo

Directed self-assembly of small molecules in living systems could enable a myriad of applications in biology and medicine, and it has been widely used to synthesize supramolecules and nano/microstructures in solution and in living cells. However, controlling self-assembly of synthetic small molecules in living animals is challenging because of the complex and dynamic in vivo physiological environment. Here we employed an optimized first-order bioorthogonal cyclization reaction to control self-assembly of a fluorescent small molecule, and demonstrated its in vivo applicability by imaging of casapae-3/7 activity in human tumor xenograft mouse models of chemotherapy. The in situ assembled fluorescent nanoparticles have been successfully imaged in both apoptotic cells and tumor tissues using three-dimensional structured illumination microscopy. This strategy combines the advantages offered by small molecules with those of nanomaterials and should find widespread use for non-invasive imaging of enzyme activity in vivo.

Pharmacological and molecular effects of platinum(II) complexes involving 7-azaindole derivatives

The in vitro antitumour activity studies on a panel of human cancer cell lines (A549, HeLa, G-361, A2780, and A2780R) and the combined in vivo and ex vivo antitumour testing on the L1210 lymphocytic leukaemia model were performed on the cis-[PtCl₂(naza)₂] complexes (1–3) involving the 7-azaindole derivatives (naza). The platinum(II) complexes showed significantly higher in vitro cytotoxic effects on cell-based models, as compared with cisplatin, and showed the ability to avoid the acquired resistance of the A2780R cell line to cisplatin. The in vivo testing of the complexes (applied at the same dose as cisplatin) revealed their positive effect on the reduction of cancerous tissues volume, even if it is lower than that of cisplatin, however, they also showed less serious adverse effects on the healthy tissues and the health status of the treated mice. The results of ex vivo assays revealed that the complexes 1–3 were able to modulate the levels of active forms of caspases 3 and 8, and the transcription factor p53, and thus activate the intrinsic (mitochondrial) pathway of apoptosis. The pharmacological observations were supported by both the histological and immunohistochemical evaluation of isolated cancerous tissues. The applicability of the prepared complexes and their fate in biological systems, characterized by the hydrolytic stability and the thermodynamic aspects of the interactions with cysteine, reduced glutathione, and human serum albumin were studied by the mass spectrometry and isothermal titration calorimetric experiments.

Effect of 2-chloro-substitution of adenine moiety in mixed-ligand gold(I) triphenylphosphine complexes on anti-inflammatory activity: the discrepancy between the in vivo and in vitro models

A series of gold(I) triphenylphosphine (PPh₃) complexes (1–9) involving 2-chloro-N6-(substituted-benzyl)adenine derivatives as N-donor ligands was synthesized and thoroughly characterized by relevant methods, including electrospray-ionization (ESI) mass spectrometry and multinuclear NMR spectroscopy. The anti-inflammatory and antiedematous effects of three representatives 1, 5 and 9 were evaluated by means of in vitro model based on the expression of pro- and anti-inflammatory cytokines and influence of the complexes on selected forms of matrix metalloproteinases secreted by LPS-activated THP-1 monocytes and in vivo model evaluating the antiedematous effect of the complexes in the carrageenan-induced rat hind-paw edema model. In addition to the pharmacological observations, the affected hind paws were post mortem subjected to histological and immunohistochemical evaluations. The results of both in vivo and ex vivo methods revealed low antiedematous and anti-inflammatory effects of the complexes, even though the in vitro model identified them as promising anti-inflammatory acting compounds. The reason for this discrepancy lies probably in low stability of the studied complexes in biological environment, as demonstrated by the solution interaction studies with sulfur-containing biomolecules (cysteine and reduced glutathione) using the ESI mass spectrometry.

Zn(II)-Chlorido complexes of phytohormone kinetin and its derivatives modulate expression of inflammatory mediators in THP-1 cells

Kinetin (N6-furfuryladenine) belongs to a group of plant growth hormones involved in cell division, differentiation and other physiological processes. One of the possible ways to obtain biologically active compounds is to complex biologically relevant natural compounds to suitable metal atoms. In this work, two structural groups of Zn(II) complexes [Zn(Lⁿ)₂Cl₂]·Solv (1–5) and [Zn(HLⁿ)Cl₃]·xLⁿ (6–7); n = 1–5, Solv = CH₃OH for 1 and 2H₂O for 2; x = 1 for 6 and 2 for 7; involving a phytohormone kinetin and its derivatives (Lⁿ) were evaluated for their ability to modulate secretion of tumour necrosis factor (TNF)-α, interleukin (IL)-1β and matrix metalloproteinase (MMP)-2 in a lipopolysaccharide (LPS)-activated macrophage-like THP-1 cell model. The penetration of the complexes to cells was also detected. The mechanism of interactions of the zinc(II) complexes with a fluorescent sensor N-(6-methoxy-8-quinolyl)-p-toluene sulphonamide (TSQ) and sulfur-containing biomolecules (l-cysteine and reduced glutathione) was studied by electrospray-ionization mass spectrometry and flow-injection analysis with fluorescence detection. The present study showed that the tested complexes exhibited a low cytotoxic effect on the THP-1 cell line (IC₅₀>40 µM), apart from complex 4, with an IC₅₀ = 10.9±1.1 µM. Regarding the inflammation-related processes, the Zn(II) complexes significantly decreased IL-1β production by a factor of 1.47–2.22 compared with the control (DMSO), but did not affect TNF-α and MMP-2 secretions. However, application of the Zn(II) complexes noticeably changed the pro-MMP-2/MMP-2 ratio towards a higher amount of maturated MMP-2, when they induced a 4-times higher production of maturated MMP-2 in comparison with the vehicle-treated cells under LPS stimulation. These results indicated that the complexes are able to modulate an inflammatory response by influencing secretion and activity of several inflammation-related cytokines and enzymes.

Cellular responses induced by Cu(II) quinolinonato complexes in human tumor and hepatic cells

BACKGROUND

Inspired by the unprecedented historical success of cisplatin, one of the most important research directions in bioinorganic and medicinal chemistry is dedicated to the development of new anticancer compounds with the potential to surpass it in antitumor activity, while having lower unwanted side-effects. Therefore, a series of copper(II) mixed-ligand complexes of the type [Cu(qui)(L)]Y · xH2O (1-6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, Y = NO3 (1, 3, 5) or BF4 (2, 4, 6), and L = 1,10-phenanthroline (phen) (1, 2), 5-methyl-1,10-phenanthroline (mphen) (3, 4) and bathophenanthroline (bphen) (5, 6), was studied for their in vitro cytotoxicity against several human cancer cell lines (A549 lung carcinoma, HeLa cervix epitheloid carcinoma, G361 melanoma cells, A2780 ovarian carcinoma, A2780cis cisplatin-resistant ovarian carcinoma, LNCaP androgen-sensitive prostate adenocarcinoma and THP-1 monocytic leukemia).

RESULTS

The tested complexes displayed a stronger cytotoxic effect against all the cancer cells as compared to cisplatin. The highest cytotoxicity was found for the complexes 4 (IC50 = 0.36 ± 0.05 μM and 0.56 ± 0.15 μM), 5 (IC50 = 0.66 ± 0.07 μM and 0.73 ± 0.08 μM) and 6 (IC50 = 0.57 ± 0.11 μM and 0.70 ± 0.20 μM) against A2780, and A2780cis respectively, as compared with the values of 12.0 ± 0.8 μM and 27.0 ± 4.6 μM determined for cisplatin. Moreover, the tested complexes were much less cytotoxic to primary human hepatocytes than to the cancer cells. The complexes 5 and 6 exhibited significantly high ability to modulate secretion of the pro-inflammatory cytokines TNF-α (2873 ± 238 pg/mL and 3284 ± 139 pg/mL for 5, and 6 respectively) and IL-1β (1177 ± 128 pg/mL and 1087 ± 101 pg/mL for 5, and 6 respectively) tested on the lipopolysaccharide (LPS)-stimulated THP-1 cells as compared with the values of 1173 ± 85 pg/mL and 118.5 ± 4.8 pg/mL found for the commercially used anti-inflammatory drug prednisone. The ability of the tested complexes to interact with sulfur-containing biomolecules (cysteine and reduced glutathione) at physiological levels was proved by electrospray-ionization mass spectrometry.

CONCLUSIONS

Overall positive results of the biological activity studies revealed that the presented complexes may represent good candidates for non-platinum anticancer drugs, however, we are aware of the fact that further and deeper studies mainly in relation to the elucidation of their mechanisms of antiproliferative action will be necessary.

[Peculiar properties of glutathione system and NADPH-generated enzymes functioning in blood of patients with drug-induced hepatitis under combined treatment with epifamin]

Activity of the glutathione antioxidant system has been studied in patients with drug-induced hepatitis treated with standart base therapy and combined with epifamin therapy. In blood serum of patients before treatment the decrease of reduced glutathione (GSH) level and the increase of glutathione peroxidase (GP) and glutathione reductase (GR) activities versus control were observed. Combined treatment with epifamin changed GSH level to the normal values. Treatment with epifamin was accompanied by pronounced increase in GP and GR activities compared with standard therapy. Activities of the NADPH-generated enzymes, glucose-6-phosphate dehydrogenase and NADP-isocitrate dehydrogenase, which decreased at this pathology, also demonstrated a more significant increase than standart treatment.

In vitro cytotoxicity, DNA cleavage and SOD-mimic activity of copper(II) mixed-ligand quinolinonato complexes

Six mixed-ligand copper(II) complexes with the composition [Cu(qui)(L)]BF(4)·xH(2)O (1-6), where Hqui=2-phenyl-3-hydroxy-4(1H)-quinolinone, L=2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), bis(2-pyridyl)amine (ambpy) (3), 5-methyl-1,10-phenanthroline (mphen) (4), 5-nitro-1,10-phenanthroline (nphen) (5) and bathophenanthroline (bphen) (6), were prepared, fully characterized and studied for their in vitro cytotoxicity on human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cancer cell lines. The overall promising results of the cytotoxicity were found for all the complexes, while the best results were achieved for complex 6, with IC(50)=2.6 ± 0.8 μM (HOS), and 1.3 ± 0.5 μM (MCF7). The interactions of the Cu(II) complexes 1-6 with calf thymus DNA were investigated by the UV-visible spectral titration. An agarose-gel electrophoretic method of oxidative damage determination to circular plasmid pUC19 was used to assess the ability of the complexes to act as chemical nucleases. A high effectiveness of DNA cleavage was observed for 2, 4 and 5. In vitro antioxidative activity of the complexes was studied by the superoxide dismutase-mimic (SOD-mimic) method. The best result was afforded by complex 1 with IC(50)=4.7 ± 1.0 μM, which corresponds to 10.2% of the native Cu,Zn-SOD enzyme activity. The ability of the tested complexes to interact with sulfur-containing biomolecules (cysteine and reduced glutathione) at physiological levels was proved by electrospray-ionization mass spectrometry (ESI-MS).

Anti-inflammatory active gold(I) complexes involving 6-substituted-purine derivatives

The gold(I) complexes of the general formula [Au(L(n))(PPh(3))]·xH(2)O (1-8; n = 1-8 and x = 0-1.5), where L(n) stands for a deprotonated form of the benzyl-substituted derivatives of 6-benzylaminopurine, were prepared, thoroughly characterized (elemental analyses, FT-IR, Raman and multinuclear NMR spectroscopy, ESI+ mass spectrometry, conductivity, DFT calculations), and studied for their in vitro cytotoxicity and in vitro and in vivo anti-inflammatory effects on LPS-activated macrophages (derived from THP-1 cell line) and using the carrageenan-induced hind paw edema model on rats. The obtained results indicate that the representative complexes (1, 3, 6) exhibit a strong ability to reduce the production of pro-inflammatory cytokines TNF-α, IL-1β and HMGB1 without influence on the secretion of anti-inflammatory cytokine IL-1RA in the LPS-activated macrophages. The complexes also significantly influence the formation of edema, caused by the intraplantar application of polysaccharide λ-carrageenan to rats in vivo. All the tested complexes showed similar or better biological effects as compared with Auranofin, but contrary to Auranofin they were found to be less cytotoxic in vitro. The obtained results clearly indicate that the gold(I) complexes behave as very effective anti-inflammatory agents and could prove to be useful for the treatment of difficult to treat inflammatory diseases such as rheumatoid arthritis.

Loss of glutathione homeostasis associated with neuronal senescence facilitates TRPM2 channel activation in cultured hippocampal pyramidal neurons

Background

Glutathione (GSH) plays an important role in neuronal oxidant defence. Depletion of cellular GSH is observed in neurodegenerative diseases and thereby contributes to the associated oxidative stress and Ca²⁺ dysregulation. Whether depletion of cellular GSH, associated with neuronal senescence, directly influences Ca²⁺ permeation pathways is not known. Transient receptor potential melastatin type 2 (TRPM2) is a Ca²⁺ permeable non-selective cation channel expressed in several cell types including hippocampal pyramidal neurons. Moreover, activation of TRPM2 during oxidative stress has been linked to cell death. Importantly, GSH has been reported to inhibit TRPM2 channels, suggesting they may directly contribute to Ca²⁺ dysregulation associated with neuronal senescence. Herein, we explore the relation between cellular GSH and TRPM2 channel activity in long-term cultures of hippocampal neurons.

Results

In whole-cell voltage-clamp recordings, we observe that TRPM2 current density increases in cultured pyramidal neurons over time in vitro. The observed increase in current density was prevented by treatment with NAC, a precursor to GSH synthesis. Conversely, treatment of cultures maintained for 2 weeks in vitro with L-BSO, which depletes GSH by inhibiting its synthesis, augments TRPM2 currents. Additionally, we demonstrate that GSH inhibits TRPM2 currents through a thiol-independent mechanism, and produces a 3.5-fold shift in the dose-response curve generated by ADPR, the intracellular agonist for TRPM2.

Conclusion

These results indicate that GSH plays a physiologically relevant role in the regulation of TRPM2 currents in hippocampal pyramidal neurons. This interaction may play an important role in aging and neurological diseases associated with depletion of GSH.