Myeloperoxidase inhibitory and radical scavenging activities of flavones from Pterogyne nitens

Two new flavone glucosides, nitensosides A and B (1, 2), together with four known compounds, sorbifolin (3), sorbifolin 6-O-beta-glucopyranoside (4), pedalitin (5), and pedalitin 6-O-beta-glucopyranoside (6) were isolated from Pterogyne nitens. Their structures were elucidated from 1D and 2D NMR analysis, as well as by high resolution mass spectrometry. All the isolated flavones were evaluated for their myeloperoxidase (MPO) inhibitory activity. The most active compound, pedalitin, exhibited IC50 value of 3.75 nM on MPO. Additionally, the radical-scavenging capacity of flavones 1-6 was evaluated towards ABTS and DPPH radicals and compared to standard compounds quercetin and Trolox.     

Development and Validation of an LC Method for Simultaneous Determination of Ascorbic Acid and Three Phenolic Acids in Sustained Release Tablets at Single Wavelength

A simple, rapid and sensitive column liquid chromatographic method was developed and validated to measure simultaneously the amount of ascorbic acid and phenolic acids at single wavelength (240 nm) in order to assess drug release profiles and drug-excipients compatibility studies for a new sustained release tablet formulation and its subsequent stability studies. A combined isocratic and linear gradient reversed-phase LC method was carried out at 240 nm. Quantification was achieved with reference to the external standards. The linearity for concentrations between 0.042 and 0.150 mg mL^?1 for ascorbic acid, 0.084–0.250 mg mL^?1 for chlorogenic acid, 0.053–0.360 mg mL^?1 for caffeic acid, and 0.016–0.250 mg mL^?1 for ferulic acid (r > 0.99 for all analytes) were established. The recovery of the active ingredients from the samples was at the range of 92.3–102.9%. Intra- and inter-day precisions were less than 2.5%. The limits of detection and quantification were 8 and 24 μg mL^?1 for ascorbic acid, 18 and 54 μg mL^?1 for chlorogenic acid, 37 and 112 μg mL^?1 for caffeic acid, and 11 and 34 μg mL^?1 for ferulic acid. The determination of the four active ingredients was not interfered by the excipients of the products. Samples were stable in the release mediums (37 °C) at least for 12 h.     

LC Method for Quantification of Lutein in Rat Plasma: Validation, and Application to a Pharmacokinetic Study

A reversed-phase LC method has been developed for quantitative analysis of lutein in rat plasma and applied to a study of the pharmacokinetics of lutein in rats. From a variety of compounds and solvents tested, astaxanthin was selected as the internal standard. n-Hexane was found to be the best solvent for extracting lutein from plasma. LC analysis of the extracts was performed on a C₁₈ column equipped with a guard pre-column. Linearity was good (r > 0.99) over the range 10–100 ng mL^?1. Recovery from plasma was 82.7–92.9% the intra-day and inter-day precision were always better than 3%. The limits of detection (LOD) and quantification (LOQ) were 2.5 and 8.3 ng mL^?1, respectively. The LC method was used to quantify lutein and zeaxanthin in rat plasma in a 36-h pharmacokinetic study in which experimental rats received a single oral dose of lutein (20 mg kg^?1). The results are presented.     

Benzobis(pyrrolopyrimidopiridazines): Molecular structure and properties of the first π‐electronic analogues of dibenzo[a,o]picene

Molecular structure, aromaticity and some spectral properties of benzobis(pyrrolopyrimidopiridazines) 2 that are the first π‐electronic analogues of the still unknown dibenzo[a,o]picene are discussed.     

Synthesis of indole-3-carboxylic acid derivatives by Pd(0)-catalyzed intramolecular alpha-arylation of beta-(2-iodoanilino) esters

beta-(2-Iodoanilino) esters undergo intramolecular alpha-arylation in the presence of Pd(PPh(3))(4) and potassium phenoxide. The reaction is a useful methodology for the preparation of indole-3-carboxylic acid ester derivatives.     

Trapping phosphate anions inside the [Ag4I] framework: Structure, bonding, and properties of Ag4I(PO4)

Orange-red Ag₄I(PO₄) crystallizes in the monoclinic system, space group P2₁/m (No. 11), with the unit cell dimensions a=9.0874(6) Å, b=6.8809(5) Å, c=11.1260(7) Å, β=109.450(1)°, and Z=4. The crystal structure is fully ordered; it comprises the silver-iodine three-dimensional positively charged framework hosting the tetrahedral PO₄³⁻ guest anions. The framework features high coordination numbers for iodine and manifold Ag-Ag bonds ranging from 3.01 to 3.46 Å. The Ag-Ag interaction is bonding, it involves silver 4d and 5s orbitals lying, together with the orbitals of iodine, just below the Fermi level. Though the orbitals of silver and iodine define the conducting properties of the title compound, the interaction between the framework and the guest anions is also important and is responsive to the number of the silver atoms surrounding the PO₄³⁻ tetrahedra. Ag₄I(PO₄) melts incongruently at 591 K and produces a mixture of the silver phosphate and an amorphous phase upon cooling. Pure Ag₄I(PO₄) is a poor conductor with a room temperature conductivity of 3×10⁻⁶ S m⁻¹. The discrepancies between the properties observed here and those reported previously in the literature are discussed.     

Cu–CeO<Subscript>2</Subscript> nanocomposites: mechanochemical synthesis,physico-chemical properties,CO-PROX activity

Catalytic systems designated for preferential oxidation of CO in the presence of H₂ are prepared by ball milling of Cu and CeO₂, a simple and cheap one-step process to synthesize such catalysts. It is found that after 60 min of milling, a mixture of 8 wt.% Cu–CeO₂ powders exhibits CO conversion of 96% and CO selectivity of about 65% at 438 K. Two active oxygen states, which are not observed in case of pure CeO2, were detected in the nanocomposite lattice and attributed to the presence of Cu in surface sites as well as in subsurface bulk sites. Correspondingly, oxidation of CO to CO₂ was found to occur in a two-stage process with T _max ≈ 395/460 K, and oxidation of H₂ to H₂O likewise in a two-stage process with T _max ≈ 465/490 K. The milled powder consists of CeO₂ crystallites sized 8–10 nm agglomerated to somewhat larger aggregates, with Cu dispersed on the surface of the CeO₂ crystallites, and to a lesser extent present as Cu₂O.

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Optimal control approach to dengue reduction and prevention in Cali,Colombia

The aim of this paper is to propose optimal strategies for dengue reduction and prevention in Cali, Colombia. For this purpose, we consider two variants of a simple dengue transmission model, epidemic and endemic, each of which is amended with two control variables. These variables express feasible control actions to be taken by an external decision‐maker. First control variable stands for the insecticide spraying and thus targets to suppress the vector population. The second one expresses the protective measures (such as use of repellents, mosquito nets, and insecticide‐treated clothes) that are destined to reduce the number of contacts (bites) between female mosquitoes (principal dengue transmitters) and human individuals. We use the Pontryagin's maximum principle in order to derive the optimal strategies for dengue control and then perform the cost‐effectiveness analysis of these strategies in order to choose the most sustainable one in terms of cost–benefit relationship. Copyright © 2016 John Wiley & Sons, Ltd.     

An Improved Protocol for Synthesis of 3‐Substituted 5‐Arylidene‐2‐thiohydantoins: Two‐step Procedure Alternative to Classical Methods

A novel method for the direct synthesis of 5‐arylidene‐2‐thiohydantoins from thioureas and aromatic aldehydes in the presence of base in ethanol was developed. Application of this efficient method allowed preparing thiohydantoins, which are difficult to synthesis by traditional methods.