Phytochemical Profile,Antioxidant Activity,and Cytotoxicity Assessment of Tagetes erecta L. Flowers

Tagetes erecta L. is a popular ornamental plant of the Asteraceae family, which is widely cultivated not only for its decorative use, but also for the extraction of lutein. Besides carotenoid representatives, which have been extensively studied, other important classes of secondary metabolites present in the plant, such as polyphenols, could exhibit important biological activities. The phytochemical analysis of a methanolic extract obtained from T. erecta inflorescences was achieved using liquid chromatography–mass spectrometry (LC-MS) techniques. The extract was further subjected to a multistep purification process, which allowed the separation of different fractions. The total extract and its fractions contain several polyphenolic compounds, such as hydroxybenzoic and hydroxycinnamic acid derivatives, flavonols (especially quercetagetin glycosides), and several aglycons (e.g., quercetin, patuletin). One of the fractions, containing mostly quercetagitrin, was subjected to two different antioxidant assays (metal chelating activity and lipoxygenase inhibition) and to in vitro cytotoxicity assessment. Generally, the biological assays showed promising results for the investigated fraction compared to the initial extract. Given the encouraging outcome of the in vitro assays, further purification and structural analysis of compounds from T. erecta extracts, as well as further in vivo investigations are justified.     

Comprehensive Thermal Characteristics of Different Cultivars of Flaxseed Oil (Linum usittatissimum L.)

The aim of this study was to describe the thermal properties of selected cultivars of flaxseed oil by the use of the differential scanning calorimetry (DSC) technique. The crystallization and melting profiles were analyzed depending on different scanning rates (1, 2, 5 °C/min) as well as oxidative induction time (OIT) isothermally at 120 °C and 140 °C, and oxidation onset temperatures (Ton) at 2 and 5 °C/min were measured. The crystallization was manifested as a single peak, differing for a cooling rate of 1 and 2 °C/min. The melting curves were more complex with differences among the cultivars for a heating rate of 1 and 2 °C/min, while for 5 °C/min, the profiles did not differ, which could be utilized in analytics for profiling in order to assess the authenticity of the flaxseed oil. Moreover, it was observed that flaxseed oil was highly susceptible to thermal oxidation, and its stability decreased with increasing temperature and decreasing heating rate. Significant negative linear correlations were found between unsaturated fatty acid content (C18:2, C18:3 n-3) and DSC parameters (OIT, Ton). Principal component analysis (PCA) also established a strong correlation between total oxidation value (TOTOX), peroxide value (PV) and all DSC parameters of thermo-oxidative stability.     

An investigation of aromaticity in hydroxybenzenes based on the study of magnetically induced current density

Hydroxybenzenes are derivatives of benzene in which one or more H atoms are replaced by OH groups. This work considers the effect of such replacement on the aromaticity of the ring, by assessing the aromaticity through the values and patterns of the magnetically induced current density. The results show that aromaticity is quenched and the quenching depends on the number and positions of the substituting OH groups. The isosurfaces of the magnitude of the current density also highlight connections between the donor and acceptor atoms forming an intramolecular hydrogen bond.     

Synthesis,structure and toxicity evaluation of ethanolamine nitro/chloronitrobenzoates: a combined experimental and theoretical study

Background

Nitroaromatic and chloronitroaromatic compounds have been a subject of great interest in industry and recently in medical-pharmaceutic field. 2-Chloro-4-nitro/2-chloro-5-nitrobenzoic acids and 4-nitrobenzoic acid are promising new agents for the treatment of main infectious killing diseases in the world: immunodeficiency diseases and tuberculosis.

Results

New ethanolamine nitro/chloronitrobenzoates were synthesized and characterized by X-ray crystallography, UV–vis, FT-IR and elementary analysis techniques. The toxicity of the compounds prepared and correspondent components was evaluated using Hydractinia echinata as test system. A significant lower toxicity was observed for nitro-derivative compared with chloronitro-derivatives and individual components. Crystallographic studies, together with the chemical reactivity and stability profiles resulted from density functional theory and ab initio molecular orbital calculations, explain the particular behavior of ethanolamine 4-nitrobenzoate in biological test.

Conclusions

The experimental and theoretical data reveal the potential of these compounds to contribute to the design of new active pharmaceutical ingredients with lower toxicity.

     

Plane Couette flow of binary gaseous mixture in the whole range of the Knudsen number

The Couette flow of binary gaseous mixtures is studied on the basis of the McCormack model of the Boltzmann equation, which was solved numerically by the discrete velocity method. The calculations were carried out for three mixtures of noble gases: neon–argon, helium–argon, and helium–xenon. The stress tensor and bulk velocity of both species were calculated for several values of the gas rarefaction in the range from 0.01 to 40 for three values of the molar concentrations: 0.1,0.5 and 0.9. The numerical solution together with an analytical solution based on the slip boundary condition cover the whole range of the gas rarefaction. It was showed that the Couette flow is weakly affected by the intermolecular interaction law.     

Synthetic protocols towards homodithiacalix[n]arenes

Synthetic procedures towards homodithiacalix[n]arenes are developed, starting from simple and readily available bifunctional aryl building blocks, by a dynamic covalent chemistry approach. Reaction of 1,3-bis(mercaptomethyl)-5-tert-butyl-2-methoxybenzene under basic conditions leads to a mixture of trimeric, tetrameric and pentameric dimethylenedithia-bridged cyclooligomers, whereas reaction of 5-tert-butyl-2-methoxy-1,3-bis(thiocyanatomethyl) benzene under reducing conditions (and subsequent oxidation) affords the homodithiacalix[4]arene macrocycle in a very selective fashion through efficient disulphide exchange chemistry.     

Different Synthesis Protocols for Co3O4–CeO2 Catalysts—Part 1: Influence on the Morphology on the Nanoscale

Co₃O₄‐modified CeO₂ (Co/Ce 1:4) was prepared by a combination of sol–gel processing and solvothermal treatment. The distribution of Co was controlled by means of the synthesis protocol to yield three different morphologies, namely, Co₃O₄ nanoparticles located on the surface of CeO₂ particles, coexistent Co₃O₄ and CeO₂ nanoparticles, or Co oxide structures homogeneously distributed within CeO₂. The effect of the different morphologies on the properties of Co₃O₄–CeO₂ was investigated with regard to the crystallite phase(s), particle size, surface area, and catalytic activity for CO oxidation. The material with Co₃O₄ nanoparticles finely dispersed on the surface of CeO₂ particles had the highest catalytic activity.     

Reactivity of an All‐Ferrous Iron–Nitrogen Heterocubane under Reductive and Oxidative Conditions

The reactivity of the all‐ferrous FeN heterocubane [Fe₄(Ntrop)₄] ( 1 ) with i) Brønsted acids, ii) σ‐donors, iii) σ‐donors/π‐acceptors, and iv) one‐electron oxidants has been investigated (trop = 5H‐dibenzo[a,d]cyclo‐hepten‐5‐yl). 1 showed self‐re‐assembling after reactions with i) and proved surprisingly inert in reactions with ii) and iii), with the exception of CO. Reductive and oxidative cluster degradation was observed in reactions with CO and TEMPO, respectively. These reactions yielded new cluster compounds, namely a trinuclear bis(μ₃‐imido) 48 electron complex in the former case and a tetranuclear all ferric μ‐oxo‐μ‐imido species in the latter case. Characterization techniques include NMR and in situ IR spectroscopy, single crystal X‐ray analysis, Mössbauer spectroscopy, cyclic voltammetry, magnetic susceptibility measurements, and DFT calculations.     

Structure- and ligand- based studies to gain insight into the pharmacological implications of histamine H3 receptor

Structural Chemistry - In the context of unknowing the experimental structure for histamine H3 receptor, which is a potential therapeutical target for numerous disorders and diseases, the...