Spondias tuberosa (Anacardiaceae) leaves: profiling phenolic compounds by HPLC‐DAD and LC–MS/MS and in vivo anti‐inflammatory activity

Spondias tuberosa is a medicinal plant used by several local communities in northeast Brazil to treat infections, digestive disorders and inflammatory conditions. The study aimed to identify and quantify the major phenolic in hydroethanolic extract of leaves from S. tuberosa and to evaluate its anti‐inflammatory potential. The chemical profile of extract was analyzed by HPLC‐DAD and HPLC–MS. The in vivo anti‐inflammatory activity was investigated in carrageenan‐induced hind paw edema and peritonitis models in mice. Identified and quantified through HPLC‐DAD or HPLC‐MS analyses of S. tuberosa extract were the following compounds: chlorogenic acid, caffeic acid, rutin and isoquercitrin. The inflammatory response to carrageenan was significantly reduced in both models by S. tuberosa extract. In hind paw edema, the edematogenic response was reduced by up to 63.6% and the myeloperoxidase activity was completely inhibited. In the peritonitis model, the total cell migration into the peritoneal cavity was reduced by up to 65%. The results obtained give evidence of the anti‐inflammatory action of S. tuberosa and suggest the potential therapeutic benefit of this plant on inflammatory conditions. The chlorogenic acid, caffeic acid, rutin and isoquercitrin identified and quantified in S. tuberosa leaves enable us to suggest that these compounds could be used as chemical markers for quality control of derivative products from this species. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis of silsesquioxanes based in (3-methacryloxypropyl)-trimethoxysilane using methacrylate monomers as reactive solvents

The polycondensation of (3-methacryloxypropyl)-trimethoxysilane in acidic conditions using different methacrylate monomers as reactive solvents resulted in incompletely condensed methacrylate-functionalized silsesquioxanes with a very large fraction of intramolecular cycles. UV-MALDI-TOF-MS analysis demonstrated that the species present after 2 weeks of reaction at 60 °C were: T₆(OH)₂, T₇(OH), T₈(OH)₂, T₉(OH), T₁₀(OH)₂ and T₁₁(OH). Analysis of samples after 30 months of storage at room temperature revealed the presence of T₁₂(OH)₂ and T₁₃(OH) species. The absence of higher molar mass oligomers after prolonged storage periods is attributed to dilution of the reacting medium, which discourages bimolecular reactions that lead to polymer growth. ²⁹Si NMR spectroscopy showed that the conversion in the polycondensation reaction was in the range 0.91-0.96. The methacrylate monomers are not involved in the hydrolysis-condensation reactions with MPTMS and therefore can be polymerized by thermal or photochemical means, thereby cross-linking the preformed nanosized cagelike silsesquioxanes. The formulations containing silsesquioxanes showed a markedly reduced content of extractable monomer after photopolymerization, which makes these resins very attractive for dental filling materials.     

X‐ray techniques applied to surface paintings of ceramic pottery pieces from Aguada Culture (Catamarca,Argentina)

X‐ray diffraction (XRD), energy dispersive spectrometry (EDS), x‐ray imaging (XRI) and scanning electron microscopy (SEM) techniques were applied to characterize and differentiate surface paintings of archeological pottery from the Aguada Ambato and Portezuelo styles (Catamarca, Argentina). Standard procedures are not always appropriate for such samples (paint layers are porous, nonplanar and discontinue). Image processing is necessary when chemical contrast is not discriminated. Soft x‐ray lines (e.g. Fe L) are more revealing because those detected come from shallower depths, clearly depicting the composition of the paint layer. These styles differ in mineralogy and chemistry suggesting that they are two distinctive entities not only on their designs but also on the materials chosen and the technology used. Aguada Portezuelo paints contain Ca (white), Fe? Mn (black), Fe? Mn? Ca (dark reddish) and Fe? Ca (reddish). The white ones correspond to gehlenite, a firing product (possible firing temperature ≥900–1000 °C); calcite and CaO occur in cases of firing temperatures <900 °C. Aguada Ambato presents difficulties for paint discrimination; only EDS spectra show slight differences. White paint from Tricolor Ambato contains mainly Pb‐phases (hatchite, anglesite, plumalsite), reddish paint resembles the paste (～Fe, hematite); reddish surfaces may have not been painted but polished. Black paint has scarce Mn–minerals. On Black Incised sherds no particular phase was identified suggesting possible organic pigments or resulting from the firing technique. The chemistry and mineralogy of the paste almost always overlap that of the paints; painted layer is irregular and partially worn by years of burial. Copyright © 2009 John Wiley & Sons, Ltd.     

Changes in the spectroelectrochemical properties of copper(II) hexacyanoferrate(III) during electrochemical insertion of alkaline ions

Journal of Solid State Electrochemistry - In this work, the influence of the electrochemical insertion of different alkali ions, e.g., lithium, sodium, and potassium, on the electrochromic...     

Thermal spreading of WO3 onto zirconia support

This study focused on preparation of tungsten oxide supported on zirconia by thermal spreading. The prepared samples were characterized by infrared spectroscopy, UV-vis diffuse reflection spectroscopy, X-ray diffraction, and also by methanol dehydration reaction. It was observed that isolated octahedral tungsten dispersed species and dispersed polytungstate were formed on zirconia surface, although some WO₃ that remained after the thermal treatment could also be detected. The presence of these species led to an increase of the number of Lewis sites and the generation of Brönsted acid sites. High calcination temperatures promoted the creation of Brönsted sites as a consequence of polytungstate species formation. The activity on methanol dehydration was also determined by the concentration of these species, whereas the isolated WO_x species were found poorly active. The correlation observed between the catalytic performance and the tungsten dispersed species, as revealed by spectroscopic techniques, evidenced the occurrence of thermal spreading of WO₃ on ZrO₂. The results presented in this work show that WO₃ thermal spreading on ZrO₂ may be effectively accomplished as predicted by thermodynamics.     

Anion Recognition by Uranyl–Salophen Derivatives as Probed by Infrared Multiple Photon Dissociation Spectroscopy and Ab Initio Modeling

The vibrational features and molecular structures of complexes formed by a series of uranyl–salophen receptors with simple anions, such as Cl^?, H^?, and HCOO^?, have been investigated in the gas phase. Spectra of the anionic complexes were studied in the $\tilde \nu $ =800–1800 cm^?1 range by mass‐selective infrared multiple photon dissociation (IRMPD) spectroscopy with a continuously tunable free‐electron laser. The gas‐phase decarboxylation of the formate adducts produces uranyl–salophen monohydride anions, which have been characterized for the first time and reveal a strong U?H bond, the nature of which has been elucidated theoretically. The spectra are in excellent agreement with the results obtained from high‐quality ab initio calculations, which provided the structure and binding features of the anion–receptor complexes.     

21α‐Fluoro‐7‐norvouacapane‐17β,21α‐lactone

The crystal structure of 21α‐fluoro‐7‐norvouacapane‐17β,21α‐lactone, C₂₀H₂₅FO₃, a new synthetic derivative of the diterpenoid 6α,7β‐di­hydroxy­vouacapan‐17β‐oic acid isolated from Pterodon polygalaeflorus Benth fruits, is described.     

Synthesis, characterization and reactivity of new complexes of titanium and zirconium containing a potential tridentate amidinato-cyclopentadienyl ligand

Group 4 metal complexes [M(eta(5)-C(5)Me(4)SiMe(2)-eta(1)-N-2R)(NMe(2))(2)] (R = pyridine, pyrazine, pyrimidine, thiazole, M = Ti; R = pyridine, thiazole; M = Zr) containing the tetramethylcyclopentadienyl-dialkylsilyl bridged amidinato as pendant ligand, were synthesized and characterized by elemental analysis, solution (1)H, (13)C and (15)N NMR spectroscopy and experimental (13)C and (15)N CPMAS in the solid state. The crystal structures of [Ti(eta(5)-C(5)Me(4)SiMe(2)-eta(1)-N-2R)(NMe(2))(2)] (R = pyridine, pyrazine, pyrimidine, thiazole) were determined by single crystal X-ray diffraction studies. All compounds exhibit a distorted tetrahedral geometry, with the ansa-monocyclopentadienyl-amido ligands acting in a bidentate mode. The [M(eta(5)-C(5)Me(4)SiMe(2)-eta(1)-N-2R)(NMe(2))(2)] (R = pyridine, thiazole; M = Zr, Ti) complexes are ethylene polymerization catalysts in the presence of MAO and they are active precursors in regioselective catalytic hydroamination operating with an anti-Markovnikov mechanism.     

Light‐mediated DNA Repair Prevents UVB‐induced Cell Cycle Arrest in Embryos of the Crustacean Macrobrachium olfersi

High levels of ultraviolet‐B (UVB) radiation can negatively affect aquatic animals. Macrobrachium olfersi is a prawn that lives in clear freshwaters and during the breeding season, females carry eggs in an external brood pouch. Therefore, we hypothesize that eggs are also exposed to environmental UVB radiation. The aim of this study was to investigate whether UVB radiation induces DNA damage and compromises cell cycle in embryos of M. olfersi. In laboratory, UVB irradiance (310 mW. cm^?2) that embryos receive in the natural environment was simulated. After irradiation, embryos were kept under different light conditions in order to recognize the presence of cell repair. UVB radiation induces DNA damage, specifically thymine dimers. After 48 h of UVB exposure, a significant decrease in the level of these dimers was observed in embryos kept under visible light while it remained constant in the dark. Moreover, under visible light and darkness, a decrease in proliferation was observed after 48 h of irradiation. An increase in PCNA expression and decrease in p53 expression were observed after, respectively, 1 and 48 h of exposure. Our results showed that UVB radiation disturbs the cell cycle and induces DNA damage in M. olfersi embryos. However, under visible light these embryos showed successful DNA repair.