Chemical characterization of unconventional palm oils from Hyophorbe indica and two other endemic Arecaceae species from Reunion Island

Abstract

Chemical characteristics of novel seed oils, yet not investigated, from three endemic Arecaceae (palm) species from Reunion Island are described. Fatty acid profiles are performed using two-dimensional gas chromatography-mass spectrometry. Carotenoid contents are determined by high performance liquid chromatography-mass spectrometry. The results of the investigations emphasize the particular composition of the unconventional red seed oil from Hyophorbe indica. Characteristic features of this oil reveal a high degree of unsaturation (50% of polyunsaturated fatty acids, with a high content (17%) of omega-3), which is possibly a unique fatty acid composition in the Arecaceae family. The two other palm oils from Dictyosperma album and Latania lontaroides contain high level of saturated fatty acids very similar to that of the edible palm oil. H. indica oil is also very rich in valuable carotenoids; in particular, lutein, β-carotene and lycopene are detected in a high content (respectively 45, 23 and 35?mg.kg^?1 in oil).     

Bromine hydrolysis control and two consecutive oscillatory domains in closed, cerium-catalyzed glyoxylic acid Belousov-Zhabotinsky systems

In closed, cerium-catalyzed glyoxylic acid Belousov-Zhabotinsky systems we found a new dynamic behavior, viz. the observation of two oscillatory regimes separated by a nonoscillatory region. Mechanisms for this intermediate nonoscillatory domain are discussed.

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New efficient construction of the ABC core of the taxoids via a sequence of consecutive cobalt(I)-mediated [2 + 2 + 2] and [4 + 2] cyclizations

[reaction: see text] A new and efficient sequence of two consecutive cyclizations, a cobalt(I)-mediated [2 + 2 + 2] cyclotrimerization and a Diels-Alder reaction, is proposed to allow the formation of the ABC core of the taxoids in 65% overall yield, starting from an acyclic polyunsaturated precursor.     

Qualitative study of in vivo melphalan adduct formation in the rat by miniaturized column-switching liquid chromatography coupled with electrospray mass spectrometry

In a general study of DNA adduct formation with melphalan, rats were intravenously injected with a single high dose (10 mg kg(-1)). Adduct formation was studied at the nucleoside level in the target organs liver, bone marrow, kidney and blood with the use of 2D liquid chromatography/tandem mass spectrometry (LC/MS/MS). Adducts of dGuo and dAdo were detected under selected reaction monitoring in liver and bone marrow 10 h after administration of melphalan. In the DNA hydrolysates from kidney and blood a Gua-melphalan adduct was found, although in very low abundance. These first results of the search for in vivo-formed melphalan adducts in the rat showed that our miniaturized LC/MS technique is useful for investigating this type of compound. More experiments will be performed in this area to gather more information about the pharmacokinetics and the quantity of adducts formed.     

On-line determination of antimony(III) and antimony(V) in liver tissue and whole blood by flow injection - hydride generation - atomic absorption spectrometry

A new analytical procedure for the speciation of antimony in liver tissues is presented here. For this purpose, a flow injection system has been developed for the treatment of samples and the determination of antimony by hydride generation - atomic absorption spectrometry. The method involves the sequential and the on-line extraction of antimony(III) and antimony(V) from solid lyophilized blood and hamsters liver tissues, with 1.5 mol l(-1) acetic acid and 0.5 mol l(-1) sulfuric acid for Sb(III) and Sb(V), respectively. Reduction of Sb(V) to Sb(III) for stibine generation is effected by the on-line pre-reduction with l-cysteine. The linear ranges were 2.5-20 and 1.0-25 mug l(-1) of Sb(III) and Sb(V), respectively. The detection limits (3sigma) were 1.0 mug l(-1) for Sb(III) and 0.5 mug l(-1) for Sb(V). The relative standard deviation values for fifteen independent measurements were 2.1 and 1.8% for Sb(III) and Sb(V), respectively. The recovery studies performed with samples of cattle liver provided results from 98 to 100% for Sb(III) and from 100 to 103% for Sb(V) for samples spiked with single species. For samples spiked with both Sb(III) and Sb(V), the recovery varied from 97 to 103% for Sb(III) and from 101 to 103% for Sb(V).     

Selective determination of antimony(III) and antimony(V) in liver tissue by microwave-assisted mineralization and hydride generation atomic absorption spectrometry

Antimony(III) and antimony(V) species have been selectively determined in liver tissues by optimizing the acidic conditions for the evolution of stibine using the reduction with sodium borohydride. The results show that a response for Sb(III) of 0.5 to 20 g l^–1 was selectively obtained from samples in a 1 mol l_–1 acetic acid medium. The best response for total antimony from 1 to 20 g l^–1 is obtained after sample treatment with a 0.5 mol l^–1 sulfuric acid and 10% w/v potassium iodide. Microwave digestion has been necessary to release quantitatively antimony species from sample slurries. The amount of Sb(V) was calculated from the difference between the value for total antimony and Sb(III) concentrations. A relative standard deviation from 2.9 to 3.1% and a detection limit of 0.15 and 0.10 g l^–1 for Sb(III) and total Sb has been obtained. The average accuracy exceeded 95% in all cases comparing the results obtained from recovery studies, electrothermal atomic absorption spectrometry and the analysis of certified reference materials.Dedicated to Professor Dr. Peter Brätter on the occasion of his 60th birthday     

Exchange interactions in oxovanadium phosphates: towards the understanding of the magnetic patterns

We report the calculations of exchange magnetic constants in a series of vanadium phosphorus oxides for which structural and magneto-chemical data are available. Four different types of dimers have been extracted from the crystal lattices in all solids studied. On the basis of a combined density functional theory broken symmetry approach, our calculations on molecular models allow us to define schemes of magnetic interactions. The largest absolute magnetic interaction is provided by the double O–P–O and di-μ-oxo bridges, suggestive of an alternating dimer chain model and an isolated dimer one for the VO(HPO₄)·0.5H₂O and α-VO(HPO₄)·2H₂O phases, respectively. Conversely, VO(HPO₄)·4H₂O is consistent with a bi-dimensional magnetic pattern whereas VO(H₂PO₄)₂ and α-VO(PO₃)₂ with three-dimensional magnetic schemes. The use of dimer models has been justified by the analysis of higher-nuclearity clusters.     

Reconstruction of thermokinetics from calorimetric data by means of numerical inverse filters

A simple method for removing the distortion due to thermal lags from calorimetric curves is described and tested. The method is based upon the use of numerical inverse filters. Its results are equivalent to those of the more sophisticated deconvolution methods, using Fourier transform analysis or state function theory. The new method is easily adapted to the on-line reconstruction of calorimetric data by means of a microprocessor.

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Zusammenfassung Eine einfache Methode zur Beseitigung der infolge thermischer Hysterese-Effekte entstandenen Verzerrungen kalorimetrischer Kurven wurde beschrieben und geprüft. Die Methode beruht auf der Anwendung numerischer Inversfilter. Die Ergebnisse sind den durch verfeinertere Dekonvolutionsmethoden unter Einsatz der Analyse durch Fouriertransformation oder durch die Zustandsfunktionstheorie erhaltenen gleichwertig. Die neue Methode läßt sich der on-line Erfassung kalorimetrischer Daten durch einen Mikroprocessor leicht anpassen.

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Résumé Une méthode simple pour la correction de la distorsion des courbes calorimétriques, amenée par l'inertie thermique, est décrite et éprouvée. La méthode est basée sur l'emploi de filtres numériques inverses. Les résultats obtenus sont équivalents à ceux fournis par des méthodes plus complexes de déconvolution, utilisant l'analyse harmonique ou la théorie des variables d'état. La nouvelle méthode peut être facilement adaptée à la correction simultanée des courbes calorimétriques au moyen d'un microprocesseur.

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Pyridazines. Part 31: synthesis and antiplatelet activity of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones

This paper describes the synthesis and the antiplatelet activity of a series of 4,5-disubstituted-6-phenyl-3(2H)-pyridazinones. Some of these compounds show a dose-dependent activity and were found to be more active than their 5-substituted analogues.