Etude physico-chimique et minéralogique comparative des attapulgites de Mbodiène (Sénégal) et de Mormoiron (France)

La valorisation des ressources locales constitue un impératif afin d’atteindre des objectifs de développement durable. Cette étude a consisté à évaluer les caractéristiques physiques, chimiques et minéralogiques d’une argile provenant de Mbodiène (Sénégal), l’attapulgite, comparativement avec un médicament antidiarrhéique, constitué d’attapulgite, dénommé Actapulgite®. L’échantillon d’attapulgite brute a été purifié avec une solution de HNO3 1M. Une étude morphologique effectuée par visualisation à la Microscopie Electronique à Balayage a montré pour les deux argiles étudiées, une structure fibreuse caractéristique de la palygorskite, représentant le minéral dominant. L’analyse chimique par la spectrométrie à fluorescence X a donné pour l’attapulgite purifiée : 65,69% Si, 7,89% Al, 5,92% Fe, 17,90% Mg, 0,43% Ca et 0,93% K contre respectivement 63,98 % Si, 12,92% Al, 10,32% Fe, 6,20% Mg, 2,48% Ca et 2,25% K pour l’Actapulgite®. La diffraction aux rayons X a montré une présence de palygorskite, quartz et carbonates dans les échantillons étudiés. L’étude des isothermes d’adsorption a montré une surface spécifique nettement plus élevée pour l’attapulgite purifiée, 138,96 m2.g-1 contre 98,72 m2.g-1 pour l’Actapulgite®. Ces résultats ont montré que l’attapulgite de Mbodiène pourrait être utilisée comme antidiarrhéique orale après lavage à l’eau et séchage.© 2016 International Formulae Group. All rights reservedMots clés: Argile, attapulgite, antidiarrhéique, SénégalEnglish Title: Physico-chemical and mineralogical comparative study of attapulgites Mbodiène (Senegal) and Mormoiron (France)English AbstractThe development of local resources is imperative to achieve sustainable development goals. This study was to assess physical, chemical and mineralogical characteristics of a clay from Mbodiène (Senegal), named attapulgite, compared with Actapulgite® (antidiarrheal drug), composed of attapulgite. A sample of attapulgite from Mbodiène was purified with a 1M HNO3 solution to remove impurities including carbonates. A morphological study using Scanning Electron Microscopy showed for both types of clay studied, a fibrous structure characteristic of palygorskite which represent major mineral. Chemical analysis by XRF spectrometry gave for purified attapulgite: 65.69% Si, 7.89% Al, 5.92% Fe, 17.90% Mg, 0.43% Ca and 0.93% K against respectively 63.98% Si, 12.92% Al, 10.32% Fe, 6.20% Mg, 2.48% Ca and 2.25% K for Actapulgite®. X-ray diffraction showed the presence of palygorskite, quartz and carbonates for both samples studied. The study of adsorption isotherms showed a significantly higher surface area for purified attapulgite, 138.96 m2.g-1 versus 98.72 m2.g-1 for Actapulgite®. These results have shown that Mbodiène attapulgite compared to Actapulgite®, could be used as an oral antidiarrheal after washing with water and drying.© 2016 International Formulae Group. All rights reserved.Keywords: Clay, attapulgite, antidiarrheal, Senega

Isolement et approche synthétique de produits naturels issus du champignon endophyte Paraconiothyrium variabile

Paraconiothyrium variabile est un champignon endophyte isolé du conifère Cephalotaxus harringtonia et a révélé un antagonisme significatif contre des phytopathogènes communs. Nous avons entrepris la caractérisation chimique des métabolites fongiques impliqués dans la relation mutualiste entre cette plante hôte et le champignon endophyte afin d'étudier leur rôle éventuel dans cet antagonisme. Le fractionnement de l'extrait AcOEt du filtrat de culture de P. variabile a révélé quatre principales familles de métabolites : a-tétralones, isocoumarines, isobenzofuranes et cyclodipeptides dans des conditions de culture différentes. La configuration absolue des trois a-tétralones portant un hydroxyle en C-4 a été déterminée comme S par analyse de leurs spectres de dichroïsme circulaire. La biotransformation de la juglone et de l'isosclérone par P. variabile a permis d augmenter les quantités d'isosclérone et d obtenir des analogues structuraux, respectivement. Des essais de dimérisation de l'isosclérone en milieu acide ont été réalisées vers le squelette naturel spirobisnaphtalène de type palmarumycine. Par ailleurs, un travail annexe apporte une contribution supplémentaire à la synthèse du précurseur linéaire des hirsutellonesParaconiothyrium variabile is an endophytic fungus isolated from the conifer Cephalotaxus harringtonia and displayed a significant antagonism against common plant pathogens. We undertook the chemical characterization of the fungal metabolites implied in the mutualistic relationship between the host plant and the endophyte in order to study their role in the observed antagonism. The analysis of the AcOEt extract of the culture filtrate of P. variabile revealed four main families of metabolites: a-tetralones, isocoumarin, isobenzofuran, and a cyclodipeptide obtained in different culture conditions. The absolute configuration of three a-tetralones with a hydroxyl at C-4 was determined S by analysis of their circular dichroism spectra. The biotransformation of juglone and isosclerone led to increased amount of isosclerone and structural analogues, respectively. Dimerization of isosclerone under acidic conditions gave the best results towards the natural spirobisnaphtalene skeleton of palmarumycins. Additionally, a contribution to the synthesis of a biomimetic linear precursor of hirsutellones was donePARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

Fatty Acid And Essential Oil Compositions Of The Seed Oil Of Five Annona Species

The fatty acid and essential oil compositions of the seed oil of Annona cherimola, A. muricata, A. reticulata, A. senegalensis and A. squamosa were investigated by GC and GC/MS spectra. About eleven fatty acids were identified of which oleic, gondoic, palmitic and stearic acids predominated in each sample, and others found in low amounts, were of more selective distribution. Fifty three volatile compounds were identified with β-caryophyllene as major compound in A. muricata, A. reticulata and A. squamosa, while terpinen-4-ol was found as major component in A. cherimola and A. senegalensis. Key words: Annonaceae, seeds, seed oil, fatty acids, essential oil, GC-MS Nig. J. Nat. Prod. and Med. Vol.8 2004: 62-6

Antagonism observed in dual culture of <i>P. variabile</i> with different strains of phytopathogens.

<p>Colonies diameters of different phytopathogens strains were measured at day fourteen in absence (gray) or in presence (white) of the endophyte <i>P. variabile</i>. Error bars indicate standard deviation (n = 3). Asterisks indicate a statistically significant decrease of the growth of the phytopathogen in the presence of the endophyte by t-test (***p<0.001).</p

Evaluation of antibacterial and antifungal activities of N-benzylthienopyrimidinone derivatives

This study is part of the biological investigation of the chemical library of molecules already described by the Laboratory of Organic Chemistry and Therapeutic Chemistry of the University of Bordeaux. The main objective was to explore the contribution of a thienyl moiety attached to the pyrimidinone nucleus, in the expression of an antimicrobial activity. The structural modifications mainly concerned the conservation or not of&nbsp; the&nbsp; benzo fragment attached to the thienyl, the saturation or not in position-1,2 of the pyrimidinone ring, the substitution on N-benzyl with more or less lipophilic units, the modification of the orientation of the thienyl fragment with, on&nbsp; the one hand, the compounds in which the sulfur is located near the N1 nitrogen (series of thieno[2,3-d]pyrimidin-4-ones) and on the other hand, compounds in which the sulfur is located near the ketone group (series of thieno[3,2-d]pyrimidin-4-ones). In general, thienyl fragment with sulfur located near the ketone group and the unsaturated pyrimidinone nucleus in the 1,2-position, seem to promote a broad spectrum of antibacterial activity, with compound 9c which is active on both Gram + bacteria and Gram – bacteria studied. The same pattern was observed for antifungal activity, which is maximum with the compounds of the thieno[3,2-d]pyrimidin-4-ones series for an MIC of 31.25 μg/ml on the strains of Candida albicans and Candida kruzei studied. Keywords: Thienopyrimidinones, antibacterial activity, antifungal activity

Structures of 1–6 isolated from <i>P. variabile.</i>

<p>All structures were assigned by detailed analysis (NMR spectroscopic and mass data).</p

Transmission electron micrographs of the hyphae of <i>F. oxysporum</i> from dual or single culture.

<p>(A) <i>F. oxysporum</i> mycelium from dual culture with the endophyte. (B) <i>F. oxysporum</i> mycelium control. Transmission electron micrographs of the mycelium of <i>F. oxysporum</i> from dual or single culture on agar plate with the endophyte <i>P. variabile</i> (14 days, 27°C) and showing cell death in the presence of the endophyte. N: nucleus. W: wall. S: septum. C: cellular fragments. V: vesicule.</p

Fragmentations of the positive ion (<i>m</i>/<i>z</i> = 295.22) identified as 13-oxo-9,11-octadecadienoic acid and of the commercial standard.

<p>Fragmentations of the positive ion (<i>m</i>/<i>z</i> = 295.22) identified as 13-oxo-9,11-octadecadienoic acid and of the commercial standard.</p