17 research outputs found

    Synthesis, crystal structure and local anti-inflammatory activity of the L-phenylalanine methyl ester derivative of dexamethasone-derived cortienic acid

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    The L-phenylalanine methyl ester derivative of dexamethasone-derived cortienic acid (DF) was synthesized and its crystal structure characterized by the X-ray diffraction method. The crystal system is orthorhombic with space group P2(1)2(1)2(1) and cell constants a = 8.2969(3) angstrom, b = 18.9358(8) angstrom, c = 20.0904(6) angstrom, V = 3156.4(2) angstrom(3) and Z = 4. Ring A of the steroid nucleus and phenyl ring in the 17 beta-side chain are almost planar. Rings B and C have a slightly distorted chair conformation, whereas ring D has an envelope conformation. The packing of DF is characterized by a network of intermolecular hydrogen bonds involving the O4 atom from one side of the steroid nucleus and O1 and F1 atoms from the other side as hydrogen bond acceptors. Apart from the intermolecular hydrogen bonds in the crystal packing, there are also numerous intramolecular hydrogen bonds of the N-H center dot center dot center dot O, C-H center dot center dot center dot O and C-H center dot center dot center dot F type. The local anti-inflammatory activity of DF was evaluated using the croton oil-induced ear oedema test. This derivative achieved maximal inhibition of ear oedema at significantly lower concentration in comparison with dexamethasone

    Crystal structure of dicholoro-(3,5-dimethyl-1H-pyrazole-1-carboxamidine-N,N )copper(II), Cu(C6H10N4)Cl-2

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    C6H10Cl2CuN4, monoclinic, P2(1)/n (no. 14), a = 7.316(2) angstrom b = 16.002(2) angstrom, c = 9.202(6) angstrom, beta = 113.15 (2)degrees, V = 990.6 angstrom(3), Z = 4, R-gt(F) = 0.054, wR(ref)(F-2) = 0.125, T = 293 K

    Importance of N-terminal proline for the promiscuous activity of 4-oxalocrotonate tautomerase (4-OT)

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    Michael addition of aldehydes to nitro-olefins is an effective method to obtain useful chiral gamma-nitroaldehydes. gamma-Nitroaldehydes are precursors for chiral gamma-aminobutyric acid analogues, which have numerous pharmacological activities and are used for the treatment of neurological disorders. A whole-cell system based on recombinantly expressed 4-oxalocrotonate tautomerase (4-OT) was developed and shown to be an effective biocatalyst for the Michael addition of branched aldehydes to beta-nitrostyrenes. The aim of this study was to investigate the influence of the substitution of the N-terminal proline with lysine and arginine, both containing a reactive epsilon-amino group, on the Michael addition catalyzed by 4-OT. First, the effects of these mutations were examined by in silico analysis, followed by the generation of three terminal lysine mutants. The generated mutants, 4-OT_K, 4-OT_PK and 4-OT_KK were tested for their ability to utilise beta-nitrostyrene (1), (E)-1-nitro-2-(2-thienyl)ethene (2) and trans-p-chloro-beta-nitrostyrene (3) as Michael acceptors with isobutanal (2-methylpropanal) as the donor. For comparison, the lithium salt of lysine was used in the same organocatalytic reactions. In general, the introduction of lysine had a negative effect on Michael additions based on overall product yields. However, additional lysine residues at the N-terminus of the protein resulted in structural changes that enhanced the activity towards 2 and 3. Therefore, the N-terminal proline is important for 4-OT-catalysed Michael-additions, but it is not essential

    Charge Density Analysis of 2-Pyridineformamide N(4)-Methylthiosemicarbazone (Z =4): Role of an Enhanced N-H center dot center dot center dot S Thioureido Dimer

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    Charge density distribution in 2-pyridineformamide N(4)-methylthiosemicarbazone (TSC4) has been determined using high-resolution X-ray diffraction data (100 K) and Hansen-Coppens multipole formalism. The results are interpreted in terms of Baders quantum theory of atoms in molecules (QTAIM), electrostatic potential analysis, and theoretical calculations (CRYSTAL09). The study highlights the molecular diSsimilarity at the electronic level. The N-H center dot center dot center dot S interactions have a dominant role in Stabilization of the TSC4 crystal Structure. As each of the four S acceptors simultaneously engages in several interactions, the focus of study is on the lone pairs electron density of these acceptors which is particularly able to adjust to the various spatial distributions of the interacting donor groups. The main structural feature of TSC4 is the formation of specific N-H center dot center dot center dot S bonded dimers between two pairs of independent molecules. These dimers are the main building block in the orkstal structure, and with the two additional N-H center dot center dot center dot S contacts they represent a significant enhancement of a typical R-2(2)(8) dirtier synthon which dominates among the thioureido-based crystal structures. Two TSC4 dimers are structurally very similar and exhibit considerable cohesive energy (-20.8 and 21.4 kcal/mol). This: type of dimer is the only structural motif that is common for S acceptors of all four independent molecules

    Electronic features and hydrogen bonding capacity of the sulfur acceptor in thioureido-based compounds. Part 2. Further insight by theoretical charge density study

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    Theoretical charge density analysis of the thioureido based compound 4-methyl-3-thiosemicarbazide (MeTSC) is used in this study with the aim to provide additional insight into electronic features of the thioureido sulfur acceptor and the corresponding D-H...S hydrogen bonding (D=N, C). The present work is motivated by our earlier experimental charge density study on the same compound that pointed out to a great flexibility of the thioureido S acceptor and its ability to adjust the lone pair electron density to the donor groups in simultaneous hydrogen bonding. Through the additional theoretical approach we were able to single out different fragments of MeTSC crystal and to carefully follow the changes in electron density properties of the S acceptors belonging to: isolated MeTSC monomers (i.e. two crystallographically independent molecules), eight D-H...S bonded dimers and MeTSC molecules placed in full crystal environment, where each S atom engages in four hydrogen bonds. Deformation density of the sulfurs lone electron pair, topological properties of D-H...S interactions and electrostatic potential are here examined in order to comprehend the mutual influence and potential cooperative effects of the four simultaneously formed interactions to each of the S acceptors. The hydrogen bonding involving thioureido S acceptor is also investigated in terms of the energetic properties of the eight real MeTSC dimers existing in the crystal structure, and additional systems MeTSC/MeOH and acetone/MeOH. The latter systems are designed with the purpose of direct comparison and ranking of interactions involving thioureido S to those involving more conventional, carbonyl O acceptor. Energetic features were thoroughly studied through electrostatic interactions energies (XD2006), cohesive energies (CRYSTAL09) and ab initio approach employing the coupled-cluster single S and doubles augmented by a perturbational correction for connected triple excitations (CCSD(T)) method. (C) 2015 Elsevier B.V. All rights reserved

    Oxidative Stress and Polymorphism of Xenobiotic-Metabolizing Enzymes in Two Patients with Severe Alpha-1-Antitrypsin Deficiency

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    Alpha-1-antitrypsin deficiency (AATD) and tobacco smoke play a key role in the pathogenesis of early-onset emphysema. Differences in AATD-related chronic obstructive pulmonary disease stages imply the existence of modifying factors associated with disease severity. We present two male patients with emphysema caused by severe AATD (PiZZ genotype). Both are former smokers and have epoxide hydrolase low-activity phenotype. Extremely high level of oxidative stress (high urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine), increased inflammation (high serum CRP), and GSTP1 105Val mutation were found in patient with a worse lung function and prognosis. These data provide more evidence that oxidative stress-related gene variants and inflammation are associated with worse symptoms of AATD-related emphysema. Therefore, prevention against severe stage of AATD-related emphysema would include early identification of the risk gene variants, cessation or never smoking, and treatment with anti-inflammatory and anti-oxidant drugs. Additionally, urinary 8-oxodG could be a candidate for predictive biomarker for routine assessment of the oxidative stress level in AATD patients

    Oxidative Stress and Genetic Variants of Xenobiotic-Metabolising Enzymes Associated with COPD Development and Severity in Serbian Adults

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    The genetic and non-genetic factors that contribute to the development of chronic obstructive pulmonary disease (COPD) are still poorly understood. We investigated the potential role of genetic variants of xenobiotic-metabolising enzymes (glutathione-S-transferase M1, GSTM1; glutathione-S-transferase T1, GSTT1; microsomal epoxide hydrolase, mEH), oxidative stress (assessed by urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine, 8-oxodG/creatinine), sex, ageing and smoking habits on susceptibility to development of COPD and its severity in Serbian population. The investigated population consisted of 153 healthy subjects (85 males and 68 females) and 71 patients with COPD (33 males and 38 females). Detection of GSTM1*null, GSTT1*null, mEH Tyr113His and mEH His139Arg gene variants was performed by PCR/RFLP method. Urinary 8-oxodG was determined using HPLC-MS/MS, and expressed as 8-oxodG/creatinine. We revealed that increased urinary 8-oxodG/creatinine and leucocytosis are the strongest independent predictors for COPD development. Increased level of oxidative stress increased the risk for COPD in males [odds ratio (OR), 95% confidence interval (CI): 8.42, 2.26-31.28], more than in females (OR, 95% CI: 3.60, 1.37-9.45). Additionally, independent predictors for COPD were ageing in males (OR, 95% CI: 1.29, 1.12-1.48), while in females they were at least one GSTM1 or GSTT1 gene deletion in combination (OR, 95% CI: 23.67, 2.62-213.46), and increased cumulative cigarette consumption (OR, 95% CI: 1.09, 1.01-1.16). Severity of COPD was associated with the combined effect of low mEH activity phenotype, high level of oxidative stress and heavy smoking. In conclusion, early identification of GSTM1*null or GSTT1*null genotypes in females, low mEH activity phenotype in heavy smokers and monitoring of oxidative stress level can be useful diagnostic and prognostic biomarkers
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