Research Center for Agricultural and Food Biotechnology

Almería, Spain

Research Center for Agricultural and Food Biotechnology

Almería, Spain
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Thielemann D.T.,Karlsruhe Institute of Technology | Wagner A.T.,Karlsruhe Institute of Technology | Lan Y.,Karlsruhe Institute of Technology | Ona-Burgos P.,University of Almeria | And 8 more authors.
Chemistry - A European Journal | Year: 2015

A new family of pentadecanuclear coordination cluster compounds (from now on simply referred to as clusters) [{Ln15(OH)20(PepCO2)10(DBM)10Cl}Cl4] (PepCO2 = 2-[{3-(((tert-butoxycarbonyl)amino)methyl)benzyl}amino]acetate, DBM = dibenzoylmethanide) with Ln = Y and Dy was obtained by using the cell-penetrating peptoid (CPPo) monomer PepCO2H and dibenzoylmethane (DBMH) as supporting ligands. The combination of an inorganic cluster core with an organic cell-penetrating peptoid in the coordination sphere resulted in a core component {Ln15(μ3-OH)20Cl}24+ (Ln = Y, Dy), which consists of five vertex-sharing heterocubane {Ln4(μ3-OH)4}8+ units that assemble to give a pentagonal cyclic structure with one Cl atom located in the middle of the pentagon. The solid-state structures of both clusters were established by single-crystal X-ray crystallography. MS (ESI) experiments suggest that the cluster core is robust and maintained in solution. Pulsed gradient spin echo (PGSE) NMR diffusion measurements were carried out on the diamagnetic yttrium compound and confirmed the stability of the cluster in its dicationic form [{Y15(μ3-OH)20-(PepCO2)10(DBM)10Cl}Cl2]2+. The investigation of both static (dc) and dynamic (ac) magnetic properties in the dysprosium cluster revealed a slow relaxation of magnetization, indicative of single-molecule magnet (SMM) behavior below 8 K. Furthermore, the χT product as a function of temperature for the dysprosium cluster gave evidence that this is a ferromagnetically coupled compound below 11 K. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Diaz-De-Cerio E.,University of Granada | Verardo V.,University of Almeria | Verardo V.,Research Center for Agricultural and Food Biotechnology | Gomez-Caravaca A.M.,University of Granada | And 2 more authors.
Journal of Chemistry | Year: 2015

Literature lacks publications about polar compounds content in infusion or guava leaves tea. Because of that, a comparison between different times of infusion and a conventional ultrasound aqueous extract was carried out. Several polar compounds have been identified by HPLC-ESI-MS and their antioxidant activity was evaluated by FRAP and ABTS assays. Four different classes of phenolic compounds (gallic and ellagic acid derivatives, flavonols, flavanones, and flavan-3-ols) and some benzophenones were determined. The quantification results reported that the order, in terms of concentration of the classes of polar compounds in all samples, was flavonols > flavan-3-ols > gallic and ellagic acid derivatives > benzophenones > flavanones. As expected, the aqueous extract obtained by sonication showed the highest content in the compounds studied. Significative differences were noticed about the different times of infusion and five minutes was the optimal time to obtain the highest content in polar compounds using this culinary method. All the identified compounds, except HHDP isomers and naringenin, were positively correlated with antioxidant activity. © 2015 Elixabet Díaz-de-Cerio et al.

Alvarez J.M.,National University of Colombia | Alvarez J.M.,University of Magdalena | Cuca L.E.,National University of Colombia | Carrasco-Pancorbo A.,University of Granada | And 4 more authors.
Biochemical Systematics and Ecology | Year: 2016

The chemical investigation of the ethanolic extract from the leaves of Persea caerulea led to the isolation of flavonoids, coumarins and three steroidal type compounds. Based on ESI-MS, UV, IR, GC-MS and 1H and 13C NMR data analysis, the structures of ten isolated compounds were identified as: quercetin (1), kaempferide-3-O-α-l-rhamnopyranoside (2), kaempferol-3-O-α-l-arabinofuranoside (3), quercetin-3-O-α-l-rhamnopyranoside (4), quercetin-3-O-β-glucoside (5), scopoletin (6), isofraxidin (7) campesterol (8), stigmasterol (9) and β-sitosterol (10). In the current research, the isolated compounds 1-9 are reported for the first time in the species Persea caerulea. © 2016 Elsevier Ltd.

Ruiz-Muelle A.B.,University of Almeria | Ona-Burgos P.,University of Almeria | Ortuno M.A.,Autonomous University of Barcelona | Ortuno M.A.,University of Minnesota | And 4 more authors.
Chemistry - A European Journal | Year: 2016

The synthesis and structural characterization of allenyl titanocene(IV) [TiClCp2(CH=C=CH2)] 3 and propargyl titanocene(IV) [TiClCp2(CH2-C≡C-(CH2)4CH3)] 9 have been described for the first time. Advanced NMR methods including diffusion NMR methods (diffusion pulsed field gradient stimulated spin echo (PFG-STE) and DOSY) have been applied and established that these organometallics are monomers in THF solution with hydrodynamic radii (from the Stokes-Einstein equation) of 3.5 and 4.1 Å for 3 and 9, respectively. Full 1H, 13C, Δ1H, and Δ13C NMR data are given, and through the analysis of the Ramsey equation, the first electronic insights into these derivatives are provided. In solution, they are involved in their respective metallotropic allenyl-propargyl equilibria that, after quenching experiments with aromatic and aliphatic aldehydes, ketones, and protonating agents, always give the propargyl products P (when carbonyls are employed), or allenyl products A (when a proton source is added) as the major isomers. In all the cases assayed, the ratio of products suggests that the metallotropic equilibrium should be faster than the reactions of 3 and 9 with electrophiles. Indeed, DFT calculations predict lower Gibbs energy barriers for the metallotropic equilibrium, thus confirming dynamic kinetic resolution. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Munzer J.E.,University of Marburg | Ona-Burgos P.,University of Almeria | Arrabal-Campos F.M.,University of Almeria | Neumuller B.,University of Marburg | And 4 more authors.
European Journal of Inorganic Chemistry | Year: 2016

The reaction of hexaphenyl-carbodiphosphorane C(PPh3)2 (CDP, 1) with BF3·OEt2 provides the corresponding difluoroborenium cation [CDP–BF2]+ (2+) through fluoride abstraction. Advanced NMR spectroscopy methods, including 19F,31P HMQC; 31P,13C HMQC; 19F,1H HOESY; 19F NOESY; 31P,13C INEPT; and 1H, 31P, 19F, and 11B diffusion NMR measurements, were performed, and they revealed strong ion pairing of 2+ with the [BF4]– counterion in chloroform solution. Structural and computational studies showed strong donor–acceptor interactions, in which the σ and π lone pairs of electrons of C(PPh3)2 donate into the vacant orbitals of the [BF2]+ fragment. The C–B bond shows the highest interaction energy of 242.9 kcal mol–1 found for the corresponding carbodiphosphorane adducts. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arrabal-Campos F.M.,University of Almeria | Ona-Burgos P.,University of Almeria | Fernandez I.,University of Almeria | Fernandez I.,Research Center for Agricultural and Food Biotechnology
Polymer Chemistry | Year: 2016

To progress on the practical issues of molecular weight prediction via diffusion NMR, the first log(Dη) vs. log(Mw) calibration curve is provided, allowing the easy and fast determination of weight-average molecular weights with no matter of the solvent used. © 2016 The Royal Society of Chemistry.

Verardo V.,University of Almeria | Verardo V.,Research Center for Agricultural and Food Biotechnology | Riciputi Y.,University of Bologna | Garrido-Frenich A.,University of Almeria | And 2 more authors.
Food Chemistry | Year: 2015

In the last years, the consumption of soy-based foods has increased due to the health benefits related to soy bioactives like phenolic compounds. Thus, in the present study, a new chromatographic method using reverse-phase high performance liquid chromatography coupled to diode array detection (RP-HPLC/DAD) was developed using a fused core pentafluorophenyl (PFP) column. The established method allowed the determination of twenty-one free phenolic compounds and eleven bound phenolics in a soy isoflavone concentrate. The method was validated in terms of precision and recovery. Intra and inter-day precision were less than 5% (% RSD) and the recovery was between 97.4% and 103.6%. Limits of quantification (LOQs) ranged between 0.093 and 0.443 μg/mL. Because of that, PFP stationary phase can be easily applied for routine determination of phenolic compounds in soy based foods. © 2015 Elsevier Ltd All rights reserved.

Lopez-Gutierrez N.,Research Center for Agricultural and Food Biotechnology | Romero-Gonzalez R.,Research Center for Agricultural and Food Biotechnology | Martinez Vidal J.L.,Research Center for Agricultural and Food Biotechnology | Frenich A.G.,Research Center for Agricultural and Food Biotechnology
Analytical Methods | Year: 2013

Triphenylmethane dyes, such as malachite green (MG), crystal violet (CV) and brilliant green (BG), have been widely used to prevent and treat infections in aquaculture products due to high efficacy, availability and low price. These compounds undergo metabolism towards reduced leucoforms, such as leucomalachite green (LMG), which can also be found in fish. The present review discusses the most relevant extraction methods as well as the main separation and detection techniques used for the determination of triphenylmethane dyes in seafood. Specifically, it is mainly focused on the application of liquid chromatography (LC) coupled with mass spectrometry (MS), including low and high resolution analysers, which are currently applied to identify and quantify dyes in seafood. © 2013 The Royal Society of Chemistry.

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