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

Analyse par RMN1H et RMN13C d'huiles essentielles et d'extraits (cedrus atlantica G. Manetti et Taxus baccata Linné)

Les produits naturels issus de la biomasse végétale connaissent depuis quelques années un succès grandissant dans de nombreuses industries (pharmacie, agroalimentaire, parfums et cosmétiques). L objectif de notre étude était, d une part de contribuer au développement des méthodes d identification et de quantification des constituants des mélanges naturels par RMN 13C et MN1H, et d autre part, de contribuer à la caractérisation chimique de végétaux poussant en Corse en vue d une valorisation potentielle. La première partie de nos travaux concerne la caractérisation chimique de l huile essentielle de bois de cèdre de l Atlas, Cedrus atlantica Manetti, introduit en Corse et présent dans diverses forêts. L analyse détaillée d un échantillon de cette huile essentielle, réalisée par combinaison de techniques chromatographiques et spectroscopiques, nous a permis d identifier divers composés possédant le squelette himachalane ou bisabolane non encore référencés dans la bibliothèque de spectres Terpènes propre au laboratoire. Il s agit de la (E)- -atlantone, de la (Z)- -atlantone, de l himachalol et de l allohimachalol. L'analyse de 48 échantillons obtenus à partir d arbres situés dans les 5 forêts référencées par l Office National des Forêts de Corse (Bavella, Bonifato, l Ospedale, Pineta et Vizzavona) et dans quelques stations isolées, associée au traitement statistique des résultats (ACP, k-means et classification hiérarchique ascendante), a permis de mettre en évidence la variabilité chimique intraspécifique de cette huile essentielle. Les échantillons se répartissent en deux groupes, de compositions chimiques très rarement décrites dans la littérature, en fonction de leur teneur élevée en -pinène (groupe I) ou en himachalol (groupe II). Notre deuxième objectif était de contribuer au développement de la méthode d analyse des taxanes en mélange par RMN 13C, développée au laboratoire. Pour ce faire, nous avons dans un premier temps, mis en œuvre deux protocoles de fractionnement d extraits au méthanol et à l éthanol de feuilles d if (Taxus baccata L.) de Corse. Nous avons ainsi identifié 11 taxanes, dont 5 non encore référencés dans la bibliothèque de spectres taxanes du laboratoire (désacétyltaxine B, 5-cinnamoyltaxicine I, 2,9-désacétyltaxinine, 3,11-cyclotaxinine NN2 et 2-désacétyltaxinine J). Dans un second temps, nous avons mis au point et validé une méthode de quantification des taxanes par RMN 13C en utilisant la 10-désacétylbaccatine III (10-DAB III) comme composé modèle et l hexane-1,6-diol comme référence interne. Cette méthode pouvant être extrapolée aux composés possédant le squelette taxane, nous l avons appliquée à la quantification de ces derniersdans les extraits au solvant de T. baccata. Dans une dernière partie, nous avons mis au point et validé (justesse, linéarité et précision des mesures) un protocole expérimental de quantification par RMN 1H sur 39 terpènes purs appartenant à différentes familles chimiques (oléfines, alcools, cétones, aldéhydes, esters, oxydes, phénylpropanoïdes, azotés) puis en mélange. Cette procédure quantitative s est avérée fiable, rapide et complémentaire de la CPG. Elle a été appliquée à la quantification des composés majoritaires de diverses huiles essentielles et elle est susceptible d être utilisée pour l analyse d un grand nombre d échantillons (dosage en routine des constituants caractéristiques) et permettre ainsi de répondre aux exigences de contrôle de qualité concernant ce type de produits naturels voire des exsudats et des extraits végétaux.Natural products isolated from plants acquired, in recent years, a growing success in many industries (pharmacy, agri-food, perfume and cosmetics). The objective of our study was to contribute, on the one hand, to the development of methods involving 13C and 1H NMR for the identification and quantification of the components of natural mixtures, and on the other hand, to the chemical characterization of plants growing in Corsica for their potential valorization. The first part of our work concerned the chemical characterization of the wood oil of Cedrus atlantica Manetti, introduced forty years ago and now growing wild in various Corsican forests. Detailed analysis, using the combination of chromatographic and spectroscopic techniques, of a wood oil sample allowed the identification of various compounds bearing the himachalane or bisabolane skeletons, which were still unreferenced in our home-made NMR spectral data library: (E)- -atlantone, (Z)- -atlantone, himachalol and allohimachalol. In addition, the analysis of 48 samples obtained from trees located in five forests referenced by the Office National des Forêts of Corsica (Bavella, Bonifato, Ospedale, Pineta and Vizzavona) as well as in a few isolated locations, associated with statistical treatment of the results (PCA, k-means and hierarchical clustering), suggested the occurrence of a chemical variability within the investigated samples. Samples are divided into two groups, whom chemical compositions were rarely described in the literature, based on their high contents in -pinene (Group I) or himachalol (Group II).Our second objective was to contribute to the development of an analytical method, based on 13C NMR, for identification and quantification of taxanes in natural mixtures. To reach this goal, we have first implemented two protocols of fractionation of methanol and ethanol extracts of leaves of yew (Taxus baccata L.). Eleven taxane derivatives, including five compounds not yet referenced in our home-made NMR spectral data library (deacetyltaxine B, 5-cinnamoyltaxicine I, 2,9-deacetyltaxinine, 3,11-cyclotaxinine NN2 and 2-deacetyltaxinine J) have been identified. Then, we have developed and validated a method for quantification of taxanes by 13C NMR using 10-DAB-III as model compound and hexane-1,6-diol as internal standard. The experimental procedure was applied to the quantification of the previously identified taxanes present in the extracts of T. baccata. This method can be extrapolated to other compounds bearing the taxane skeleton. In the last part of this work, we developed a method that allows direct quantitative determination of terpenes in natural mixtures, using 1H NMR. The quantitative procedure was checked and validated (accuracy, linearity and precision of measurements) with 39 commercially available terpenes of different chemical families (olefins, alcohols, ketones, aldehydes, esters, oxides, phenylpropanoids and a nitrogen-containing compound). This method is proved to be reliable, fast and complementary with GC. It may be used for the analysis of a large number of samples (routine determination of characteristic constituents) and for quality control of essential oils and solvent extracts.CORTE-BU (200962101) / SudocSudocFranceF

Chemical composition of extracts from Chaetomorpha Linum. A potential use in cosmetic Industry.

International audienc

Rapid Screening of Chemical Compositions from Gracilaria dura and Hypnea musciformis (Rhodophyta) Growing wild in Corsican lagoon.

International audienc

Rapid screening of chemical compositions of Gracilaria dura and Hypnea musciformis (Rhodophyta) from Corsican lagoon

International audienceMarine macroalgae are important ecological and commercial biomass resources to many regions of the world. They are valuable food resources and are most promising sources of bioactive compounds for the cosmetic industries. Phytochemical off-line investigation by the separation and identification of secondary metabolites are time, material and human resource consuming. Thus, in our studies, a rapid gas chromatography-mass spectrometry (GC-MS) on-line analysis with pretreatment (chemical derivatisations) was adapted for chemical profiling of two wild growing algae: Gracilaria dura and Hypnea musciformis from Corsica (France). Two GC-MS derivatisation methods were used: transmethylation for the fatty acids (FAs), and trimethylsilylation for compounds which bear -OH/-NH function. The application of the method on Gracilaria dura, and Hypnea musciformisleads to an identification of FAs, phytosterols, esters, simple phenolic compounds, and sugars from n-pentane, ethyl acetate (EtOAc) and n-butanol (n-BuOH) extracts. This method is quick and low-cost for chemical profiling of marine biomass. It could be applied not only by the fundamental but also cosmetic industrial research. In addition, this study showed that all algae extracts had modest DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activities and the n-BuOH extract of Hypnea musciformis had a high total phenol content

Composition and Variability of Leaf Oil from Monodora crispata -13C NMR Identification of Heat-sensitive Compounds

International audienceThe composition of four samples of essential oil isolated from the leaves of individual Monodora crispata trees growing wild in an Ivorian forest(Adiopodoumé) were investigated by a combination of chromatographic (GC(RI)) and spectrometric (GC-MS, 13C NMR) techniques. In total, fifty-sevencompounds accounting for 92.3-98.7% of the whole composition were identified. These oils were characterized by the preeminence of sesquiterpenehydrocarbons and the content of the main components varied substantially from sample to sample. Two samples were largely dominated by germacrene D(67.3% and 76.3%, respectively), a third sample was represented by germacrene D (28.3%), germacrene C (14.3%), -elemene (12.1%) and -elemene (9.3%)and the fourth sample was characterized by 3-dimethylallylindole (15.1%), germacrene D (12.0%) and cyperene (7.8%). 13C NMR spectroscopy wasparticularly efficient for the identification of heat-sensitive compound

Chemical composition of extracts from chaetomorpha linum (Miller) kütz. A potential use in the cosmetic industry

International audienceThe chemical composition of extracts from the green alga Chaetomorpha linum (Miller) Kütz., growing wild in Corsican pond, were investigated by GC-MS (derivatisation) and 13C NMR spectroscopy. Eighteen compounds have been identified from both pentane and ethyl acetate extract. Fatty acids, mainly saturated (SFA) are the main compounds from the pentane extract, whereas components of the sterols family are major compounds from the ethyl acetate extract. Besides usual fatty acids founds in green alga extract, we report herein the identification of unusual compounds. Indeed 12 compounds (3, 7-18) were identified for the first time in a Chaetomorpha species. Among them three diterpenes bearing the abietane skeleton (abietic acid 12, dehydro-abietic acid 13 and methyl dehydro-abietate 14) were identified for the first time from a marine source. This chemical composition could be a chemotaxonomic characteristic from the linum species found in the Corsican area