Chemical composition of laurencia obtusa extract and isolation of a new C15-acetogenin

A new C15-acetogenin, sagonenyne (20), exhibiting an unusual single tetrahydropyran ring was isolated from an ethyl acetate extract of Laurencia obtusa collected on the Corsican coastline. Its structure was established by detailed NMR spectroscopic analysis, mass spectrometry, and comparison with literature data. Twenty-three known compounds were identified in the same extract by means of column chromatography steps, using a (13)C-NMR computer aided method developed in our laboratory. In addition to sesquiterpenes, which represent the main chemical class of this extract, diterpenes, sterols, and C15-acetogenins were identified. The crude extract was submitted to a cytotoxicity assay and was particularly active against THP-1 cells, a human leukemia monocytic cell line.info:eu-repo/semantics/publishedVersio

Impact de la chloration sur la formation de sous-produits de désinfection à caractère odorant

Afin de déterminer l'origine d'odeurs pouvant apparaître lors du traitement de l'eau, la chloration des acides aminés phénylalanine, valine, leucine et alanine a été étudiée. Le suivi de la réaction, pour différents temps de contact et doses de chlore, a mis en évidence la formation de chloraldimines. Ces molécules sont stables dans l'eau: elles présentent des demi-vies de l'ordre de plusieurs dizaines d'heures à température ambiante et plus à basse température. Les limites de détection olfactive de ces produits sont inférieures au micro gramme par litre. Au vu des teneurs potentielles de l'eau en acides aminés, ces composés sont susceptibles de se former lors de la désinfection finale et de persister assez dans le réseau de distribution pour générer des nuisances olfactives au robinet du consommateur. Nous avons mis au point une méthode d'analyse permettant la détection de ces chloraldimines à l'état de traces. Nous avons appliqué cette méthode à l'analyse d'eaux réelles.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Influence of complexation phenomena with multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid in water.

Article de revue (Article scientifique dans une revue à comité de lecture)International audienceExperimental and theoretical influence of multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid (AMPA) was studied in pure water and in one surface water. The procedure chosen, based on derivatization with FMOC-Cl, HPLC separation, and fluorescence detection, appears highly affected at cations concentrations current in natural waters. A detailed speciation study performed with the VMINTEQ software strongly suggests that the complexes formed between analytes and cations do not dissociate during the reaction and do not react with the derivatization agent, so that only the free forms are derivatized. These results point out the necessity of a pre-treatment to prevent these interferences, even in low salinity waters. The different ways conceivable are discussed in terms of kinetic and thermodynamic considerations.</p

Potential of extracts from Saponaria officinalis and Calendula officinalis to modulate in vitro rumen fermentation with respect to their content in saponins

International audienceSaponins have the potential to favorably modulate rumen fermentation, but there is generally a lack of the chemical structures associated with the described effects. The activity of extracts from&nbsp;Calendula officinalisand&nbsp;Saponaria officinalis&nbsp;in the rumen was evaluated&nbsp;in vitro. The&nbsp;S. officinalis&nbsp;root extract, reduced CH4production by 8.5% and increased total VFA concentration by 25.2%.&nbsp;C. officinalis&nbsp;and&nbsp;S. officinalis&nbsp;root extracts and the&nbsp;S. officinalis&nbsp;aerial part extract decreased the acetate to propionate ratio from 8.6 to 17.4%, according to the extract. An HPLC-ELSD analysis indicated that the saponin content ranged from 43.6 to 57.6 mg/g of dry matter (DM) in the&nbsp;C. officinalis&nbsp;extracts and from 224.0 to 693.8 mg/g of DM in the&nbsp;S. officinalis&nbsp;extracts, expressed as the hederacoside C equivalent. Identification of the saponin compounds present in the extracts by HPLC–MSn&nbsp;suggested that the saponin profile modulated the biological activities, showing the importance of determining the structure of saponins when evaluating extracts.</p

Odorous Products of the Chlorination of Phenylalanine in Water: Formation, Evolution, and Quantification

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Phenolic compounds in apple juices - Method of quantification by UHPLC-UV and UHPLC-MS/MS

An UPHLC-UV/MS/MS method was developed for separation and quantification of major polyphenolic compounds present in apple juice. The main classes of polyphenols studied here are monomeric or polymeric flavan-3-ols, phenolic acids, flavonols and dihydrochalcones. compounds were quantified simultaneously with the two detection systems, i.e. with UV-PDA detection and ESI-triple quadrupole mass detection used in the selected reaction monitoring (SRM) mode. Each method (UHPLC-UV and UHPLC-SRM) was assessed with 2 different apple juice samples and linearity, limit of detection and quantification (LOD and LOQ), accuracy and precision tests were realized on the 15 major compounds. Despite the validation of the UHPLC-UV and UHPLC-SRM methods, significantly different results were obtained by comparing UHPLC-UV and UHPLC-SRM quantifications. Three groups of polyphenols were observed, the first one with equivalent results between the two quantification methods (in most cases), and the two others with overestimated or underestimated results when comparing UHPLC-UV and UHPLC-SRM quantifications.Cartographie génétique des composés phénoliques de la pomm

Impact of UV-irradiation on the formation of odorous chloroaldimines in drinking water

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Article Comparison of Two Methods, UHPLC-UV and UHPLC-MS/MS, for the Quantification of Polyphenols in Cider Apple Juices

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