Phenylalanine-Based AMPA Receptor Antagonist as the Anticonvulsant Agent with Neuroprotective Activity—In Vitro and In Vivo Studies

Trying to meet the multitarget-directed ligands strategy, a series of previously described aryl-substituted phenylalanine derivatives, reported as competitive antagonists of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, were screened in vitro for their free-radical scavenging and antioxidant capacity in two different assays: ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity fluorescent (ORAC-FL) assays. The most active antioxidants 1 and 8 were further examined to evaluate their neuroprotective properties in vitro. In this study, compound 1 showed a significant neuroprotective effect against the neurotoxin 6-hydroxydopamine in neuroblastoma SH-SY5Y and IMR-32 cell lines. Both compounds also showed prevention from high levels of reactive oxygen species (ROS) in SH-SY5Y cells. Furthermore, the desired monoamine oxidase B (MAO-B) inhibition effect (IC₅₀ = 278 ± 29 nM) for 1 was determined. No toxic effects up to 100 µM of 1 and 8 against neuroblastoma cells were observed. Furthermore, in vivo studies showed that compound 1 demonstrated significant anticonvulsant potential in 6-Hz test, but in neuropathic pain models its antiallodynic and antihyperalgesic properties were not observed. Concluding, the compound 1 seems to be of higher importance as a new phenylalanine-based lead candidate due to its confirmed promise in in vitro and in vivo anticonvulsant activity.     

Postdiagenetic Changes in Kerogen Properties and Type by Bacterial Oxidation and Dehydrogenation

A significant part of organic carbon found on the earth is deposited as fossil organic matter in the lithosphere. The most important reservoir of carbon is shale rocks enriched with organic matter in the form of kerogen created during diagenesis. The purpose of this study was to analyze whether the bacterial communities currently inhabiting the shale rocks have had any impact on the properties and type of kerogen. We used the shale rock located on the Fore-Sudetic Monocline, which is characterized by oil-prone kerogen type II. We were able to show that shale rock inhabited by bacterial communities are characterized by oxidized and dehydrated kerogen type III (gas-prone) and type IV (nonproductive, residual, and hydrogen-free). Bacterial communities inhabiting shale rock were dominated by heterotrophs of the Proteobacteria, Firmicutes, and Actinobacteria phyla. Additionally, we detected a number of protein sequences in the metaproteomes of bacterial communities matched with enzymes involved in the oxidative metabolism of aliphatic and aromatic hydrocarbons, which may potentially contribute to the postdiagenetic oxidation and dehydrogenation of kerogen. The kerogen transformation contributes to the mobilization of fossil carbon in the form of extractable bitumen dominated by oxidized organic compounds.     

The Effect of Antiretroviral Therapy on SIRT1, SIRT3 and SIRT6 Expression in HIV-Infected Patients

Human Immunodeficiency Virus (HIV) infection and the chronic use of combined antiretroviral therapy (cART) may affect the occurrence of certain disturbances in the body. There is growing interest in sirtuins–enzymes involved in the regulation of many metabolic processes in the organism and in the pathogenesis of many diseases which also exhibit potential antiviral activity. The aim of the study was to investigate the connection of cART to the expression of Sirtuin 1 (SIRT1), Sirtuin 3 (SIRT3) and Sirtuin 6 (SIRT6) in HIV-infected men. The plasma levels of sirtuins were measured before and one year after cART, and related to HIV viral load, lymphocytes T CD4+ and CD8+ count as well as the applied cART. The levels of sirtuins in plasma were measured in HIV-infected patients (n = 53) and the control group (n = 35) by immunoassay methods. There were statistically significant (p < 0.05) differences between SIRT6 in the HIV-infected patients before therapy and in the subgroups, depending on the count of lymphocytes T CD8+. There were significant differences in the levels of SIRT1 depending on the applied treatment regimen. The obtained results indicate the most significant changes in the expression of SIRT6 in the course of HIV infection and suggest an influence of the type of cART on the level of SIRT1, which indicates its important role in the course of HIV.     

The Current State of Knowledge on Salvia hispanica and Salviae hispanicae semen (Chia Seeds)

Chia seeds (Salviae hispanicae semen) are obtained from Salvia hispanica L. This raw material is distinguished by its rich chemical composition and valuable nutritional properties. It is currently referred to as “health food”. The purpose of the present work was to perform a literature review on S. hispanica and chia seeds, focusing on their chemical composition, biological properties, dietary importance, and medicinal uses. The valuable biological properties of chia seeds are related to their rich chemical composition, with particularly high content of polyunsaturated fatty acids, essential amino acids, polyphenols, as well as vitamins and bioelements. The available scientific literature indicates the cardioprotective, hypotensive, antidiabetic, and antiatherosclerotic effects of this raw material. In addition, studies based on in vitro assays and animal and human models have proven that chia seeds are characterized by neuroprotective, hepatoprotective, anti-inflammatory, and antioxidant properties. These properties indicate a valuable role of chia in the prevention of civilization diseases. Chia seeds are increasingly popular in functional food and cosmetic and pharmaceutical industries. That is attributed not only to their desirable chemical composition and biological activity but also to their high availability. Nevertheless, S. hispanica is also the object of specific biotechnological studies aimed at elaboration of micropropagation protocols of this plant species.     

Effect of heat treatment on the structure and morphology of ZnO nanorod array and its composite with titania precursor

ABSTRACT

Effects of the elevated temperature on the structure evolution of the ZnO nanorod array (ZNA) and their hybrid nanocomposite with layered (tetramethyl)ammonium titanate (LTMAT) prepared by the liquid phase deposition were investigated. The vertically oriented ZnO nanorods were deposited on a quartz plate by a chemical bath deposition method and then they were penetrated by the LTMAT using the dip-coating method from the water solution. As a result of such an experimental procedure, an assembly composed of the ZNA with LTMAT was obtained and called hybrid nanocomposite. Since the LTMAT converts to TiO₂ upon subsequent sintering at 350 °C, it can be regarded as TiO₂ precursor for the thermal treatment experiments. The experiments with ZNA and their hybrid nanocomposite at the elevated temperature revealed coalescence of the deposited ZnO nanorods and crystallization of zinc titanate with Zn₂TiO₄ stoichiometry.     

Characterization of an all Sol-Gel Electrochromic Device WO3/Ormolyte/CeO2-TiO2

Electrochemical lithium intercalation in thin films of CeO₂-TiO₂ and WO₃, prepared by the sol-gel technique was investigated with cyclic voltammetry and spectroelectrochemical techniques in propylene carbonate solutions. A solid state system having the configuration WO₃/Ormolyte/CeO₂-TiO₂ has been assembled. The solid electrolyte, an organically modified electrolyte (ormolyte), was prepared with different [O]/[Li] ratios. The transmittance variation of this system during a potentiostatic step from –0.7 V to 0.8 V was about 35% at 550 nm.     

Monitoring of NO2 in the ambient air with passive samplers before and after a road reconstruction event

Nitrogen dioxide (NO₂) concentrations were used to evaluate the air quality before and after the infrastructural change of an important traffic artery in Mortsel, Antwerp (Belgium). During the reconstruction works two pairs of traffic lanes were reduced to one in each direction. Two sampling campaigns were conducted: the first one before the works in 2003 and the second one in 2005, after the road works were finished. Sampling was performed on a weekly base with the use of passive diffusion tubes on the streets, and also indoors in nearby houses. The samples were analyzed by ion chromatography, from which data the NO₂ concentrations in air could be calculated. These results were compared with NO₂ values from the air monitoring station 42R801 of the Flemish Environment Agency in Borgerhout, Antwerp. On the base of different NO₂ concentrations, correlated well with the traffic density, sampling locations were classified into three groups as follows: 1) ‘heavily polluted’ (heavy traffic); 2) ‘moderately polluted’ (medium traffic); or 3) ‘less polluted’ (low traffic density). Sampling sites located further from the road works, enclosed to the group ‘less polluted’, showed the lowest NO₂ concentrations. The highest NO₂ level was found for the locations close to reconstruction works, which belonged to the group ‘heavily polluted’. The contribution of NO₂ was at the same level before and after the road works. During the first campaign it ranged from 30 ± 7 µg/m³ to 71 ± 11 µg/m³ and during the second sampling it was between 36 ± 17 µg/m³ and 73 ± 17 µg/m³. These modernization works had no impact on preventing the traffic-related pollutant as NO₂ and as a consequence no significant effect on the air quality in the studied region. It has been proven that the impact of traffic on the air quality is unmistakably high and simply reduction of the number of the traffic lanes, intended to discourage the traffic flow, had apparently no environmentally advantageous effect.     

Two isomorphous ZnII/CoII complexes with tri‐tert‐butoxysilanethiol and histamine,and (4‐hydroxymethyl‐1H‐imidazole‐κN)bis(tri‐tert‐butoxysilanethiolato‐κ2O,S)zinc(II)

The complexes [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)cobalt(II), [Co(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], and [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], are isomorphous. The central Zn^II/Co^II ions are surrounded by two S atoms from the tri‐tert‐butoxysilanethiolate ligand and by two N atoms from the chelating histamine ligand in a distorted tetrahedral geometry, with two intramolecular N—H...O hydrogen‐bonding interactions between the histamine NH₂ groups and tert‐butoxy O atoms. Molecules of the complexes are joined into dimers via two intermolecular bifurcated N—H...(S,O) hydrogen bonds. The Zn^II atom in [(1H‐imidazol‐4‐yl‐κN³)methanol]bis(tri‐tert‐butoxysilanethiolato‐κ²O,S)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₄H₆N₂O)], is five‐coordinated by two O and two S atoms from the O,S‐chelating silanethiolate ligand and by one N atom from (1H‐imidazol‐4‐yl)methanol; the hydroxy group forms an intramolecular hydrogen bond with sulfur. Molecules of this complex pack as zigzag chains linked by N—H...O hydrogen bonds. These structures provide reference details for cysteine‐ and histidine‐ligated metal centers in proteins.     

Unusual photochemical C-N bond cleavage in the novel methyl 2-chloro-3-methyl-2H-azirine-2-carboxylate

The structure, preferred conformers, vibrational spectrum, and photochemical behavior of the novel azirine, methyl 2-chloro-3-methyl-2H-azirine-2-carboxylate (MCMAC) were investigated in low-temperature matrixes and in the neat solid amorphous state by infrared spectroscopy and quantum-chemical calculations. Two conformers of the compound were observed in argon, krypton, and xenon matrixes, in agreement with the DFT(B3LYP)/6-311++G(d,p) and MP2/6-311++G(d,p) theoretical calculations. Both conformers were found to exhibit the carboxylic ester group in the cis conformation, differing in the arrangement defined by the O=C-C-Cl dihedral angle (cis and trans, for Ct and Cc forms, respectively). The Ct conformer was found to be the most stable conformer in the gaseous phase as well as in both argon and krypton matrixes, whereas the more polar Cc conformer became the most stable form in the xenon matrix and in the neat solid amorphous phase. In situ broadband UV (lambda > 235 nm) excitation of matrix-isolated MCMAC led to azirine ring C-C and C-N bond cleavages, the latter process corresponding to the most efficient reaction channel. The photochemical cleavage of the C-N bond had never been previously observed in the case of aliphatic 2H-azirines. Two electron withdrawing substituents (methoxycarbonyl group and chlorine atom) are connected to the azirine ring in the novel MCMAC azirine. The simultaneous presence of these two groups accelerates intersystem crossing toward the triplet state where cleavage of the C-N bond takes place. The primary photoproducts resulting from the C-N and C-C ring-opening reactions were also found to undergo further photochemical decarbonylation or decarboxylation reactions.     

Synthesis of β-ketophosphonates with electron rich β-aryl groups as useful organophosphorus reagents in lignans synthesis

Investigation of the oxidation reaction of electron rich alkoxy substituted β-aryl β-hydroxyphosphonates to corresponding β-ketophosphonates, which may be utilized in syntheses of lignans with various oxidizing agents (PCC, PDC, SIBX, CAN, Oxone^®, KMNO₄/SiO₂, KMnO₄/MS 4 Å, KMnO₄/CuSO₄, KMnO₄/CuSO₄/Al₂O₃, MnO₂, CrO₃/SiO₂, H₂O₂/salen) is described. The effect of oxidants and reaction conditions on the reaction efficiency and yield was also investigated.