References of "Frederich, Michel"
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See detailA la découverte de médicaments d'origine naturelle pour lutter contre le paludisme
Frederich, Michel ULg

Scientific conference (2009, October 08)

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See detailEvaluation des potentialités antiplasmodiales de plantes utilisées en médecine traditionnelle au Burkina Faso
Jansen, Olivia ULg; Nikiéma, Jean-Baptiste; Angenot, Luc ULg et al

Conference (2009, October 07)

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See detailAntisickling properties of divanilloylquinic acids isolated from Fagara zanthoxyloides Lam. (Rutaceae).
Ouattara, Badiore; Jansen, Olivia ULg; Angenot, Luc ULg et al

in Phytomedicine : International Journal of Phytotherapy and Phytopharmacology (2009), 16(2-3), 125-129

Fagara zanthoxyloides Lam. (syn. Zanthoxylum zanthoxyloides) (Rutaceae) is the most cited Fagara species for the treatment and the prevention of sickle cell disease crisis. Sickle cell anemia (SCA) is a ... [more ▼]

Fagara zanthoxyloides Lam. (syn. Zanthoxylum zanthoxyloides) (Rutaceae) is the most cited Fagara species for the treatment and the prevention of sickle cell disease crisis. Sickle cell anemia (SCA) is a public health problem in many countries particularly in Africa. The present study was designed to evaluate the antisickling properties of three isomeric divanilloylquinic acids (3,4-O-divanilloylquinic acid or burkinabin A; 3,5-O-divanilloylquinic acid or burkinabin B and 4,5-O-divanilloylquinic acid or burkinabin C) identified previously by LC/MS/NMR analysis in the root bark of F. zanthoxyloides [Ouattara et al., 2004. LC/MS/NMR analysis of isomeric divanilloylquinic acids from the root bark of Fagara zanthoxyloides Lam. Phytochemistry 65, 1145-1151]. The three isomers showed interesting antisickling properties which increased from burkinabins A to C. [less ▲]

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See detailMétabolomique - Identification de métabolites (biomarqueurs) par RMN 2D et LC-NMR
Frederich, Michel ULg

Conference (2009, January 28)

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See detailA la découverte de médicaments d'origine naturelle pour lutter contre le paludisme
Frederich, Michel ULg

Scientific conference (2009, January 27)

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See detailAntimalarial compounds isolated from plants used in traditional medicine.
Bero, Joanne; Frederich, Michel ULg; Quetin-Leclercq, Joelle

in Journal of Pharmacy & Pharmacology (2009), 61(11), 1401-33

OBJECTIVES: This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given ... [more ▼]

OBJECTIVES: This review covers the compounds with antiplasmodial activity isolated from plants published from 2005 to the end of 2008, organized according to their phytochemical classes. Details are given for substances with IC50 values < or = 11 microm. KEY FINDINGS: Malaria is a major parasitic disease in many tropical and subtropical regions and is responsible for more than 1 million deaths each year in Africa. The rapid spread of resistance encourages the search for new active compounds. Nature and particularly plants used in traditional medicine are a potential source of new antimalarial drugs as they contain molecules with a great variety of structures and pharmacological activities. SUMMARY: A large number of antimalarial compounds with a wide variety of structures have been isolated from plants and can play a role in the development of new antimalarial drugs. Ethnopharmacological approaches appear to be a promising way to find plant metabolites that could be used as templates for designing new derivatives with improved properties. [less ▲]

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See detailThiaminylated adenine nucleotides — chemical synthesis, structural characterization and natural occurrence
Frederich, Michel ULg; Delvaux, David ULg; Gigliobianco, Tiziana ULg et al

in FEBS Journal (2009), 276(12), 32563268

Thiamine and its three phosphorylated derivatives (mono-, di- and triphosphate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine ... [more ▼]

Thiamine and its three phosphorylated derivatives (mono-, di- and triphosphate) occur naturally in most cells. Recently, we reported the presence of a fourth thiamine derivative, adenosine thiamine triphosphate (AThTP), produced in E. coli in response to carbon starvation. Here, we show that the chemical synthesis of AThTP leads to another new compound, adenosine thiamine diphosphate (thiaminylated ADP, AThDP), as a side product. The structure of both compounds was confirmed by mass spectrometry and 1H-, 13C- and 31P-NMR and some of their chemical properties were determined. Our results show an upfield shifting of the C-2 proton of the thiazolium ring in adenosine thiamine derivatives compared to the conventional thiamine phosphate derivatives. This modification of the electronic environment of the C-2 proton might be explained by a through-space interaction with the adenosine moiety, suggesting an U-shaped folding of adenosine thiamine derivatives. Such a structure where the C-2 proton is embedded in a closed conformation can be located using molecular modeling as an energy minimum. In E. coli, AThTP may account for 15% of total thiamine under energy stress. It is less abundant in eukaryotic organisms, but is consistently found in mammalian tissues and in some cell lines. Using a HPLC method, we show for the first time that AThDP may also occur in small amounts in E. coli and in vertebrate liver. The discovery of two natural thiamine adenine compounds further highlights the complexity and diversity of thiamine biochemistry, which is not restricted to the cofactor role of thiamine diphosphate. [less ▲]

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See detailIn vitro antiplasmodial activity of plants used in Benin in traditional medicine to treat malaria
Bero, Joanne; Ganfon, Habib; Jonville, Marie ULg et al

in Journal of Ethnopharmacology (2009), 122

Aim of the study: The aim of the studywas to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to ... [more ▼]

Aim of the study: The aim of the studywas to evaluate the in vitro antiplasmodial activity of crude extracts of 12 plant species traditionally used in Benin for the treatment of malaria in order to validate their use. Materials and methods: For each species, dichloromethane, methanol and total aqueous extracts were tested. The antiplasmodial activity of extracts was evaluated using the measurement of the plasmodial lactate dehydrogenase activity on chloroquine-sensitive (3D7) and resistant (W2) strains of Plasmodium falciparum. The selectivity of the different extractswas evaluated using the MTT test on J774 macrophagelike murine cells and WI38 human normal fibroblasts. Results: The best growth inhibition of both strains of Plasmodium falciparum was observed with the dichloromethane extracts of Acanthospermum hispidum DC. (Asteraceae) (IC50 =7.5 g/ml on 3D7 and 4.8 g/ml on W2), Keetia leucantha (K. Krause) Bridson (syn. Plectronia leucantha Krause) (Rubiaceae) leaves and twigs (IC50 = 13.8 and 11.3 g/ml on 3D7 and IC50 = 26.5 and 15.8 g/ml on W2, respectively), Carpolobia lutea G.Don. (Polygalaceae) (IC50 = 19.4 g/ml on 3D7 and 8.1 g/ml on W2) and Strychnos spinosa Lam. (Loganiaceae) leaves (IC50 = 15.6 g/ml on 3D7 and 8.9 g/ml on W2). All these extracts had a low cytotoxicity. Conclusion: Our study gives some justifications for the traditional uses of some investigated plants. [less ▲]

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See detailIn Vitro Anticancer Potential of Tree Extracts from the Walloon Region Forest.
Frederich, Michel ULg; Marcowycz, Aline; Cieckiewicz, Ewa ULg et al

in Planta Medica (2009), 75(15), 1634-1637

Forty-eight extracts from 16 common Belgian trees from the Walloon Region forest were evaluated for IN VITRO growth inhibitory activity against the human LoVo colon cancer, PC3 prostate cancer, and U373 ... [more ▼]

Forty-eight extracts from 16 common Belgian trees from the Walloon Region forest were evaluated for IN VITRO growth inhibitory activity against the human LoVo colon cancer, PC3 prostate cancer, and U373 glioblastoma cell lines. Our study was performed with the aim of selecting plant candidates in order to later isolate new anticancer compounds from an easily affordable tree material. Extracts from ALNUS GLUTINOSA (stem bark), CARPINUS BETULUS (leaves and stem bark), CASTANEA SATIVA (stem bark), FAGUS SYLVATICA (leaves), ILEX AQUIFOLIUM (leaves), LARIX DECIDUA (leaves), QUERCUS PETRAEA (stem bark), and QUERCUS ROBUR (leaves) showed for the first time potent IN VITRO growth inhibitory activity and could become easily affordable sources of potential new anticancer agents. Root extracts from ROBINIA PSEUDOACACIA, already known for containing cytotoxic lectins, also showed interesting activity. [less ▲]

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See detailTriclisia sacleuxii (Pierre) Diels (Menispermaceae), a potential source of acetylcholinesterase inhibitors.
Murebwayire, Sengabo; Ingkaninan, Kornkanok; Changwijit, Kanokwan et al

in Journal of Pharmacy & Pharmacology (2009), 61(1), 103-7

OBJECTIVES: To search for compounds possibly useful for the treatment of Alzheimer's disease. METHODS: Alkaloid fractions from the roots, stems and leaves of Triclisia sacleuxii (Menispermaceae) and pure ... [more ▼]

OBJECTIVES: To search for compounds possibly useful for the treatment of Alzheimer's disease. METHODS: Alkaloid fractions from the roots, stems and leaves of Triclisia sacleuxii (Menispermaceae) and pure bisbenzylisoquinoline alkaloids isolated from the roots (phaeanthine, N-methylapateline, 1,2-dehydroapateline and gasabiimine) were assessed for acetylcholinesterase inhibitory activity. KEY FINDINGS: All extracts and compounds tested inhibited acetylcholinesterase to varying degrees; the leaf tertiary alkaloid fractions and the root quaternary alkaloid fractions exhibited the strongest inhibitory potential (90% at 0.1 mg/ml). The leaf tertiary alkaloid fraction was selected for further analysis (the quaternary alkaloids, which are too polar for absorption and brain distribution, were presumed to be clinically uninteresting). TLC bioautography using Ellman's reagent allowed the detection of acetylcholinesterase inhibitors and the isolation of the major active constituent, which was identified as lindoldhamine, a one-bridged bisbenzylisoquinoline alkaloid. Lindoldhamine displayed high acetylcholinesterase inhibitory activity with a 50% inhibition concentration in the micromolar range. CONCLUSIONS: All T. sacleuxii alkaloid fractions tested exhibited anti-acetylcholinesterase activity; isolated bisbenzylisoquinoline alkaloids showed weak-to-high inhibition depending on their structural features. Structure modification could provide interesting derivatives with enhanced anti-acetylcholinesterase activity. [less ▲]

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See detailFagraldehyde, a Secoiridoid Isolated from Fagraea fragrans
Jonville, Marie ULg; Capel, Marie; Frederich, Michel ULg et al

in Journal of Natural Products (2008), 71(12), 2038-2040

A secoiridoid aglycone with atypical skeleton, named fagraldehyde (1), together with several known secoiridoids (gentiopicroside (2), sweroside (3) and swertiamarin (4)) were isolated from the bark and ... [more ▼]

A secoiridoid aglycone with atypical skeleton, named fagraldehyde (1), together with several known secoiridoids (gentiopicroside (2), sweroside (3) and swertiamarin (4)) were isolated from the bark and leaves of Fagraea fragrans collected in Cambodia. The conformations of 1 were evaluated on the basis of molecular modeling and NOESY correlations. A hypothetical biogenesis of fagraldehyde was proposed to explain the unusual skeleton. Compound 1 was weakly active in vitro against Plasmodium falciparum. [less ▲]

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See detail1H NMR metabolomic approach of the laser-induced choroidal neovascularization in mice
Lambert, Vincent ULg; Frederich, Michel ULg; Rousseau, Rousseau et al

Poster (2008, August)

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See detailEthnopharmacologie et paludisme au Burkina Faso : sélection de 13 espèces à potentialités antiplasmodiales méconnues
Jansen, Olivia ULg; Frederich, Michel ULg; Tits, Monique ULg et al

in Ethnopharmacologia (2008), 41

Dans la recherche de nouvelles substances actives contre les Plasmodium, les flores non explorées du Sud constituent une source potentielle privilégiée de nouveaux médicaments antipaludéens. Dans ce ... [more ▼]

Dans la recherche de nouvelles substances actives contre les Plasmodium, les flores non explorées du Sud constituent une source potentielle privilégiée de nouveaux médicaments antipaludéens. Dans ce travail, nous avons suivi une démarche ethnopharmacologique afin de répertorier et de sélectionner des végétaux intéressants à étudier en laboratoire pour leurs propriétés antiplasmodiales. Notre travail de recensement des espèces utilisées contre la malaria au Burkina Faso nous a permis de répertorier 72 espèces végétales utilisées seules ou en association dans le traitement traditionnel du paludisme dans ce pays d’Afrique de l’Ouest. Finalement, treize espèces ont été sélectionnées et dix-sept échantillons végétaux ont été récoltés au Burkina Faso pour évaluation de leurs propriétés antiplasmodiales en laboratoire. Les principaux critères de sélection ont été : leur utilisation traditionnelle contre la malaria et le fait que ces plantes n’aient pas (ou peu) été étudiées sur le plan antiplasmodial. Les liens de chimiotaxonomie éventuels avec des plantes déjà connues pour leurs propriétés antiplasmodiales ainsi que les possibilités de valorisation des espèces au niveau local (MTA) ont également été considérés. [less ▲]

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See detailA la recherche de substances naturelles à potentialités antiplasmodiales et cytotoxiques
Frederich, Michel ULg

Scientific conference (2008, June 19)

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See detailTheoretical and Experimental Investigations of Organic Acids/Cyclodextrin Complexes and Their Consequences Upon the Formation of Miconazole/Cyclodextrin/Acid Ternary Inclusion Complexes
Barillaro, Valéry; Dive, Georges ULg; Bertholet, Pascal et al

in International Journal of Pharmaceutics (2008), 347(1-2), 62-70

(1)H NMR spectrometry, FT-IR spectroscopy, as well as molecular modeling at the AM1 level and normal mode analysis were used to characterise the interactions and the formation of inclusion complexes ... [more ▼]

(1)H NMR spectrometry, FT-IR spectroscopy, as well as molecular modeling at the AM1 level and normal mode analysis were used to characterise the interactions and the formation of inclusion complexes between three organic acids: maleic, fumaric, L-tartaric acids and betaCD. In aqueous medium, the complexation was confirmed by (1)H NMR spectroscopy using two-dimensional technique. The stable geometries of the complexes were determined by molecular modeling. Experimental infrared frequencies were assigned on the base of the vibrational normal mode calculation at the fully optimized geometry for the inclusion complexes. All the results point out the presence of stable inclusion complexes between acids and betaCD at the solid state. These results show the double role of the acid. Correlated with the theoretical and experimental data previously obtained for the miconazole/CD/acids complexes, in function of both acids and CDs structures, the acids can either stabilize the complexes by formation of a multicomponent complex or form acid/CD inclusion complexes, hindering the guest inclusion. [less ▲]

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See detailPotential antimalarial activity of indole alkaloids
Frederich, Michel ULg; Tits, Monique ULg; Angenot, Luc ULg

in Transactions of the Royal Society of Tropical Medicine & Hygiene (2008), 102(1), 11-19

New antimalarial treatments are now urgently required, following the emergence of resistance to the most used drugs. Natural products contribute greatly to the therapeutic arsenal in this area, including ... [more ▼]

New antimalarial treatments are now urgently required, following the emergence of resistance to the most used drugs. Natural products contribute greatly to the therapeutic arsenal in this area, including artemisinin and quinine (and atovaquone, semi-synthetic). Among the natural products, indole alkaloids represent an interesting class of compounds. Screening carried out to date has revealed several substances active in vitro under the micromolar range and with a good selectivity index. This review covers the indole alkaloids with high antiplasmodial activity (in vitro and in vivo) isolated from natural sources, and is organized according to the different chemical structures of the alkaloids. [less ▲]

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