References of "Frederich, Michel"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailIn vitro cytotoxicity of some medicinal plants from Georgian amaryllidaceae
Jokhadze, Malkhaz; Eristavi, Lina; Kutchukhidze, Jumber et al

in Phytotherapy Research (2007), 21(7), 622-624

Using an ethnomedical data approach, some Georgian plants, which are used in Georgian traditional medicine for cancer or non-cancer diseases, were collected and evaluated for cytotoxic activity. The ... [more ▼]

Using an ethnomedical data approach, some Georgian plants, which are used in Georgian traditional medicine for cancer or non-cancer diseases, were collected and evaluated for cytotoxic activity. The cytotoxic effect of the methanol extracts of species from the genera Galanthus and Leucojum was evaluated in vitro on three human cell lines (Hela, ephitheloid cervix carcinoma; HCT-116, colon carcinoma; HL-60, acute myeloid leukaemia). Cell type cytotoxic specificity was observed for some extracts. Overall, the HCT-116 cells were much more sensitive to most of the extracts than were the other cell lines. Plants that showed pronounced cytotoxic activity will be further evaluated for the possible isolation of active antitumour compounds. Copyright (C) 2007 John Wiley [less ▲]

Detailed reference viewed: 93 (9 ULg)
Full Text
Peer Reviewed
See detailIn vivo antimalarial activity of isosungucine, an indolomonoterpenic alkaloid from Strychnos icaja
Philippe, Geneviève ULg; De Mol, Patrick ULg; Angenot, Luc ULg et al

in Planta Medica (2007), 73(5), 478-479

Isosungucine (1) is a quasi-symmetric bisindolomonoterpenoid alkaloid isolated from the roots of Strychnos icaja. The in vivo antimalarial activity against the P. vinckei petteri murine strain was ... [more ▼]

Isosungucine (1) is a quasi-symmetric bisindolomonoterpenoid alkaloid isolated from the roots of Strychnos icaja. The in vivo antimalarial activity against the P. vinckei petteri murine strain was determined. In the Peters 4-day suppressive test, 1 suppressed the parasitemia by almost 50 percent on day 4 at the dose of 30 mg/kg by intraperitoneal route. [less ▲]

Detailed reference viewed: 61 (8 ULg)
Full Text
Peer Reviewed
See detailStudy of the physicochemical properties in aqueous medium and molecular modeling of tagitinin C/cyclodextrin complexes
Ziemons, Eric ULg; Dive, Georges ULg; Debrus, Benjamin ULg et al

in Journal of Pharmaceutical & Biomedical Analysis (2007), 43(3), 910-919

The inclusion complexes of tagitinin C with beta-, 2,6-di-O-methyl-beta- and gamma-cyclodextrin (CyD) was investigated in aqueous medium. The stoichiometric ratios and stability constants (K(f)) which ... [more ▼]

The inclusion complexes of tagitinin C with beta-, 2,6-di-O-methyl-beta- and gamma-cyclodextrin (CyD) was investigated in aqueous medium. The stoichiometric ratios and stability constants (K(f)) which describe the extent of formation of the complexes have been determined by UV spectroscopy and direct current tast polarography (DC(tast)), respectively. For each complex, a 1:1 molar ratio was formed in solution and the trend of stability constants was K(f) (2,6-di-O-methyl-beta-CyD)>K(f) (gamma-CyD)>K(f) (beta-CyD). The effect of molecular encapsulation on the photochemical conversion of tagitinin C was evaluated. No significant protection efficacy was noticed with beta- and gamma-CyD for the complexed drug with the respect to the free one. On the other hand, the photochemical conversion rate was slowed in presence of 2,6-di-O-methyl-beta-CyD. Data from (1)H NMR and ROESY experiments provided a clear evidence of formation of inclusion complexes. The lactone, the ester and the unsaturated ketone parts of tagitinin C inserted into the wide rim of the CyDs torus. These experimental results were confirmed by the molecular modeling using semiempirical Austin Model 1 (AM1) method. [less ▲]

Detailed reference viewed: 79 (14 ULg)
Full Text
Peer Reviewed
See detailDiscovery of a natural thiamine adenine nucleotide
Bettendorff, Lucien ULg; Wirtzfeld, Barbara; Makarchikov, Alexander F et al

in Nature Chemical Biology (2007), 3(4), 211-212

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine ... [more ▼]

Several important cofactors are adenine nucleotides with a vitamin as the catalytic moiety. Here, we report the discovery of the first adenine nucleotide containing vitamin B1: adenosine thiamine triphosphate (AThTP, 1), or thiaminylated ATP. We discovered AThTP in Escherichia coli and found that it accumulates specifically in response to carbon starvation, thereby acting as a signal rather than a cofactor. We detected smaller amounts in yeast and in plant and animal tissues. [less ▲]

Detailed reference viewed: 102 (38 ULg)
Full Text
Peer Reviewed
See detailNematocidal compounds from the seeds of Balanites aegyptiaca isolation and structure elucidation.
Gnoula, C.; Guissou, P.; Duez, P. et al

in International Journal of Pharmacology (2007), 3(3), 280-284

A study was conducted to characterize the anthelmintic activity and to isolate the main nematocidal agent of B. aegyptiaca plant. The anthelmintic activity was evaluated in vitro by means of an original ... [more ▼]

A study was conducted to characterize the anthelmintic activity and to isolate the main nematocidal agent of B. aegyptiaca plant. The anthelmintic activity was evaluated in vitro by means of an original anthelmintic assay using Caenorhabditis elegans as a biological model. Fluorescence microscopy was used for the determination of the percentage of worm death. The structure elucidation was based on NMR, mass spectroscopic analysis and chemical methods. A bioassay-directed fractionation of the aqueous extract of B. aegyptiaca led to the isolation of balanitin-7 (also named diosgenin 3beta-O-beta-D-xylopyranosyl-(1->3)-beta-D-glucopyranosyl-(1->4)-[alpha- L-rhamnopyranosyl-(1->2)]-beta-D-glucopyranoside), as being the principal nematicidal agent. These data indicate that balanitin-7 has an appreciable nematocidal activity, which is not mediated by inducing an anti-acetylcholinesterase activity. [less ▲]

Detailed reference viewed: 102 (0 ULg)
Full Text
See detailPotentialités antipaludiques des alcaloïdes indoliques
Frederich, Michel ULg; Philippe, Geneviève ULg; Tits, Monique ULg et al

in Actualités de Chimie Thérapeutique (2007), 33

This paper will be mainly illustrated with references to selected antiplasmodial compounds:- indole alkaloid analogues of emetine isolated from Strychnos usambarensis and Pogonopus tubulosus-other ... [more ▼]

This paper will be mainly illustrated with references to selected antiplasmodial compounds:- indole alkaloid analogues of emetine isolated from Strychnos usambarensis and Pogonopus tubulosus-other bisindole alkaloids isolated from Loganiacea and Apocynaceae -indoloquinolines (cryptolepine and analogues) -indolo quinazoline-6,12-diones and derivatives from Strobilanthes and other sources -aminopolycyclic beta-carbolines ( manzamines) !solated from Indo-Pacific sponges. The paper will be finally also focused on the design of chemosensitizers that are capable of reversing in vitro chloroquine resistance( case of some mono-indole alkaloids). [less ▲]

Detailed reference viewed: 36 (4 ULg)
Full Text
Peer Reviewed
See detailValidation of a high-performance thin-layer chromatography/densitometry method for the quantitative determination of glucosamine in a herbal dietary supplement
Esters, Virginie ULg; Angenot, Luc ULg; Brandt, V. et al

in Journal of Chromatography. A (2006), 1112(1-2), 156-164

A quantitative densitometric high-performance thin-layer chromatography (HPTLC) method was developed for the determination of glucosamine in a dietary supplement containing dried extracts of the main ... [more ▼]

A quantitative densitometric high-performance thin-layer chromatography (HPTLC) method was developed for the determination of glucosamine in a dietary supplement containing dried extracts of the main plants traditionally used for rheumatic disorders. The HPTLC method was chosen in order to circumvent the tedious and time-consuming sample preparation steps necessarily performed before using HPLC methods when analysing complex matrixes. Glucosamine was separated from the plant extracts on a silica gel 60 F(254) HPTLC plate using a saturated mixture of 2-propanol-ethyl acetate-ammonia solution (8%) (10:10:10, v/v/v). The plates were developed vertically up to a distance of 80 mm. For visualization, the plate was dipped into a modified anisaldehyde reagent and heated at 120 degrees C for 30 min in a drying oven. Glucosamine appeared as brownish-red chromatographic zones on a colourless background. Densitometric quantification was performed at lambda = 415 nm by reflectance scanning. The HPTLC method was successfully validated by applying the novel validation protocol proposed by a commission of the "Societe Francaise des Sciences et Techniques Pharmaceutiques" (SFSTP). In the pre-validation phase, the appropriate response function was determined, while in the validation phase the method showed good performance thereby fulfilling its objective of quantifying accurately. The relative standard deviations for repeatability and intermediate precision were between 4.9 and 8.6%. Moreover, the method was found to be accurate, as the two-sided 95% beta-expectation tolerance interval did not exceed the acceptance limits of 85 and 115% on the whole analytical range (800-1,200 ng of glucosamine). [less ▲]

Detailed reference viewed: 79 (14 ULg)
Full Text
Peer Reviewed
See detailScreening of 14 alkaloids isolated from Haplophyllum A. Juss. for their cytotoxic properties
Jansen, Olivia ULg; Akhmedjanova, Valentina; Angenot, Luc ULg et al

in Journal of Ethnopharmacology (2006), 105(1-2), 241-245

Further to a systematic chemotaxonomic study of Uzbek Haplophyllum A. Juss. plants selected on ethnopharmacological data, 14 alkaloids were screened for their cytotoxic properties. As a first selection ... [more ▼]

Further to a systematic chemotaxonomic study of Uzbek Haplophyllum A. Juss. plants selected on ethnopharmacological data, 14 alkaloids were screened for their cytotoxic properties. As a first selection for interesting compounds, each alkaloid was tested against two human cancer cell lines (HeLa and HCT-116), using WST-1 reagent. Of the 14 alkaloids, 5 were cytotoxic when tested against the HeLa line with an IC50 < 100 microM. These five compounds consisted of three furoquinolines: skimmianine; haplopine and gamma-fagarine and two pyranoquinolones: flindersine and haplamine. Only haplamine was active against the HCT-116 line. The cytotoxic properties of these five alkaloids were further investigated against five additional human cancer cell lines. Their structure-activity relationships will be discussed. Of these five pre-selected alkaloids, only haplamine showed significant cytotoxic activity against all the tested cell lines. This is the first report of the cytotoxic activity of haplamine. Finally, this pyranoquinolone alkaloid was tested here against 14 different cancer cell lines and against normal skin fibroblasts. [less ▲]

Detailed reference viewed: 82 (20 ULg)
See detailApplication of NMR to Identification of Metabolites
Frederich, Michel ULg

Scientific conference (2006, April 07)

Detailed reference viewed: 9 (4 ULg)
Full Text
Peer Reviewed
See detailFive labdane diterpenoids from the seeds of Aframomum zambesiacum
Kenmogne, Marguerite; Prost, Elise; Harakat, Dominique et al

in Phytochemistry (2006), 67(5), 433-438

Five labdane diterpenoids, (3-5), zambesiacolactone A (7) and zambesiacolactone B (8), were isolated from the seeds of Aframomum zambesiacum (Baker) K. Schum., along with five known labdanes and a linear ... [more ▼]

Five labdane diterpenoids, (3-5), zambesiacolactone A (7) and zambesiacolactone B (8), were isolated from the seeds of Aframomum zambesiacum (Baker) K. Schum., along with five known labdanes and a linear sesquiterpene, nerolidol. Their structures were elucidated by spectroscopic analysis. Their antiplasmodial activity was evaluated in vitro against Plasmodium falciparum. Compound 3 was the most active with an IC50 value of 4.97 mu M. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 67 (7 ULg)
Full Text
Peer Reviewed
See detailStudy of the interaction of antiplasmodial strychnine derivatives with the glycine receptor
Philippe, Geneviève ULg; Nguyen, Laurent ULg; Angenot, Luc ULg et al

in European Journal of Pharmacology (2006), 530(1-2), 15-22

Strychnos icaja Baill. (Loganiaccae) is a liana found in Central Africa known to be an arrow and ordeal poison but also used by traditional medicine to treat malaria. Recently, many dimeric or trimeric ... [more ▼]

Strychnos icaja Baill. (Loganiaccae) is a liana found in Central Africa known to be an arrow and ordeal poison but also used by traditional medicine to treat malaria. Recently, many dimeric or trimeric indolomonoterpenic alkaloids with antiplasmodial properties have been isolated from its rootbark. Since these alkaloids are derivatives of strychnine, it was important, in view of their potential use as antimalarial drugs, to assess their possible convulsant strychnine-like properties. In that regard, their interaction with the strychnine-sensitive glycine receptor was investigated by whole-cell patch-clamp recordings on glycine-gated currents in mouse spinal cord neurons in culture and by [H-3]strychnine competition assays on membranes from adult rat spinal cord. These experiments were carried out on sungucine (leading compound of the chemical class) and on the antiplasmodial strychnogucine B (dimeric) and strychnohexamine (trimeric). In comparison with strychnine, all compounds interact with a very poor efficacy and only at concentrations > I mu M with both [H-3]strychnine binding and glycine-gated currents. Furthermore, the effects of strychnine and protostrychnine, a monomeric alkaloid (without antiplasmodial activity) also isolated from S. icaja and differing from strychnine only by a cycle opening, were compared in the same way. The weak interaction of protostrychnine confirms the importance of the G cycle ring structure in strychnine for its binding to the glycine receptor and its antagonist properties. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 61 (12 ULg)