References of "Frederich, Michel"
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See detailBiodiversity and ecosystem services: think functional!
Uyttenbroeck, Roel ULg; Hatt, Séverin ULg; Paul, Aman ULg et al

Poster (2014, February 07)

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant ... [more ▼]

During the last years, several studies and reviews have considered the relation between biodiversity and ecosystem functioning or the provision of ecosystem services. Many studies found that plant functional traits and plant functional diversity (FD) are key drivers in this relation in terrestrial ecosystems. Researchers used different methods to obtain a gradient in plant FD to examine the effect on ecosystem services, going from observational studies of natural communities to synthetic assemblages. Furthermore, different methods exist to quantify plant FD going from simple functional trait richness to indices, distance-based frameworks and the division into FD components. In the AgricultureIsLife project, we set up a field experiment aiming to examine the biodiversity – ecosystem service relation in agricultural context. The experiment consists of perennial wildflower strips with different plant functional diversities in an arable field with conventional crop production. The wildflower strips were sown as synthetic assemblages but are subject to natural succession during the following years. We monitor the evolution of FD from the sowing to the establishment of a typical wildflower strip using Rhao’s quadratic entropy index to quantify FD. In addition, the flower strips will be monitored for four ecosystem services they are expected to provide: pollination, pest control, biodiversity support and provision of valuable compounds. [less ▲]

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See detail« Les plantes qui nous soignent : de la tradition à la médecine moderne »
Frederich, Michel ULg

Scientific conference (2014, January 20)

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See detailAn Easy, Convenient Cell and Tissue Extraction Protocol for Nuclear Magnetic Resonance Metabolomics.
Matheus, Nicolas ULg; Hansen, Sylvain ULg; Rozet, Eric ULg et al

in Phytochemical analysis : PCA (2014), 25

INTRODUCTION: As a complement to the classic metabolomics biofluid studies, the visualisation of the metabolites contained in cells or tissues could be a very powerful tool to understand how the local ... [more ▼]

INTRODUCTION: As a complement to the classic metabolomics biofluid studies, the visualisation of the metabolites contained in cells or tissues could be a very powerful tool to understand how the local metabolism and biochemical pathways could be affected by external or internal stimuli or pathologies. Therefore, extraction and/or lysis is necessary to obtain samples adapted for use with the current analytical tools (liquid NMR and MS). These extraction or lysis work-ups are often the most labour-intensive and rate-limiting steps in metabolomics, as they require accuracy and repeatability as well as robustness. Many of the procedures described in the literature appear to be very time-consuming and not easily amenable to automation. OBJECTIVE: To find a fast, simplified procedure that allows release of the metabolites from cells and tissues in a way that is compatible with NMR analysis. METHODS: We assessed the use of sonication to disrupt cell membranes or tissue structures. Both a vibrating probe and an automated bath sonicator were explored. RESULTS: The application of sonication as the disruption procedure led to reproducible NMR spectral data compatible with metabolomics studies. This method requires only a small biological tissue or cell sample, and a rapid, reduced work-up was applied before analysis. The spectral patterns obtained are comparable with previous, well-described extraction protocols. CONCLUSION: The rapidity and the simplicity of this approach could represent a suitable alternative to the other protocols. Additionally, this approach could be favourable for high- throughput applications in intracellular and intratissular metabolite measurements. Copyright (c) 2014 John Wiley & Sons, Ltd. [less ▲]

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See detailAntiplasmodial anthraquinones and hemisynthetic derivatives from the leaves of Tectona grandis (Verbenaceae)
Kopa, T.K.; Tchinda Tiabou, Alembert ULg; Tala, M.F. et al

in Phytochemistry Letters (2014), 8

Chemical investigation of the methanol extract of the leaves of Tectona grandis led to the isolation of one new anthraquinone derivative, grandiquinone A (3-acetoxy-8-hydroxy-2-methylanthraquinone) (1 ... [more ▼]

Chemical investigation of the methanol extract of the leaves of Tectona grandis led to the isolation of one new anthraquinone derivative, grandiquinone A (3-acetoxy-8-hydroxy-2-methylanthraquinone) (1), along with nine known compounds: 5,8-dihydroxy-2-methylanthraquinone (2), hydroxysesamone (3), 3-hydroxy-2-methylanthraquinone (4), quinizarine (5), betulinic acid (6), ursolic acid (7), tectograndone (8), corosolic acid (9) and sitosterol 3-O-β-d-glucopyranoside (10). Compounds 2 and 3 were isolated for the first time from the leaves of this plant, while 5 has never been reported from the genus Tectona. Hydroxysesamone (3) and tectograndone (8) were subjected to cyclisation and acetylation reactions to afford two hemisynthetic derivatives, 6,9-dihydroxy-2,2-(dimethyldihydropyrano)-3,4-dihydro-2H-benzo[g]chromene-5,10-dione (11) and acetyltectograndone (12) respectively, which are reported here for the first time. The ethyl acetate-soluble portion, some of the isolated compounds and hemisynthetic derivatives were evaluated for their antiplasmodial activity against the multidrug-resistant Dd2 strain of Plasmodium falciparum. Compound 3 showed a prominent activity, while 2, 8, 9, 11 and 12 showed significant in vitro anti-malarial activity. Compound 1 was weakly active in this test. The structures of the compounds were elucidated by spectroscopic methods and comparison of the data with the literature. [less ▲]

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See detailIn vitro antitrypanosomal and antiplasmodial activities of crude extracts and essential oils of Ocimum gratissimum Linn from Benin and influence of vegetative stage.
Kpadonou Kpoviessi, Benedicta G. H.; Kpoviessi, Salome D. S.; Yayi Ladekan, Eleonore et al

in Journal of ethnopharmacology (2014), 155(3), 1417-23

ETHNOPHARMACOLOGICAL RELEVANCE: Different parts of Ocimum gratissimum Linn are largely used in folk medicine for the treatment of many diseases, some of which related to parasitical infections as fevers ... [more ▼]

ETHNOPHARMACOLOGICAL RELEVANCE: Different parts of Ocimum gratissimum Linn are largely used in folk medicine for the treatment of many diseases, some of which related to parasitical infections as fevers and headaches. In order to validate their use and to clarify the plant part which possesses the best antiparasitic properties, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils and crude extracts from leaves, stems and seeds of Ocimum gratissimum as well as their cytotoxicity. MATERIALS AND METHODS: The essential oils and ethanol crude extracts of leaves and stems of Ocimum gratissimum from Benin, were obtained in pre and full flowering stages. Seeds obtained only in full flowering stage, were also extracted. The oils were isolated by hydrodistillation and analyzed by GC/MS and GC/FID. Extracts and essential oils were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity and toxicity was assessed against Artemia salina Leach. RESULTS: The essential oils and non-volatile crude extracts of Ocimum gratissimum were more active on Trypanosoma brucei brucei than on Plasmodium falciparum (3D7). This activity varies according to the vegetative stage (pre and full flowering) and the plant part (seeds, stems and leaves) extracted. The best growth inhibition of Trypanosoma brucei brucei was observed with ethanol crude extracts of leaves (IC50=1.66 +/- 0.48 mug/mL) and seeds (IC50=1.29 +/- 0.42 mug/mL) in full flowering stage with good selectivity (SI>10). The chemical composition of the essential oil from aerial parts (47 compounds), characterized by the presence as main constituents of p-cymene, thymol, gamma-terpinene, beta-myrcene and alpha-thujene, depends on the vegetative stage. The oil contained some minor compounds such as myrcene (IC50=2.24 +/- 0.27mug/mL), citronellal (IC50=2.76 +/- 1.55mug/mL), limonene (IC50=4.24 +/- 2.27mug/mL), with good antitrypanosomal activities. These oils and crude extracts were not toxic against Artemia salina Leach and had a low cytotoxicity except leaves and seeds ethanol extracts obtained in full flowering which showed toxicity against CHO and WI38 cells. CONCLUSIONS: Our study shows that ethanol crude extracts of leaves and seeds of Ocimum gratissimum in full flowering stage can be a good source of antitrypanosomal agents. This is the first report about the relation between the plant part extracted, the vegetative stage of the plant, the antitrypanosomal and antiplasmodial activities and the cytotoxicity of essential oils and non-volatile extracts of Ocimum gratissimum from Benin. [less ▲]

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See detailAntioxidant fractions and phenolic constituents from leaves of Pluchea carolinensis and Pluchea rosea
Perera Cordoba, Wilmer Hervet; Wauters, Jean-Noël ULg; Kevers, Claire ULg et al

in Free Radicals and Antioxidants (2014), 4(2), 1-7

Abstract: Objective: To evaluated the antioxidant potential of several polar fractions of P. carolinensis and P. rosea as well as pure chemicals, some of them quantified in both species by HPLC. Methods ... [more ▼]

Abstract: Objective: To evaluated the antioxidant potential of several polar fractions of P. carolinensis and P. rosea as well as pure chemicals, some of them quantified in both species by HPLC. Methods: The antioxidant potential of polar fractions and pure chemicals were assayed by 2,2-diphenyl-1-picrylhydrazyl and oxygen radical potential methods. The phenolic content was performed by using Folin–Ciocalteu’s reagent. Specific phenolic acids and flavonoids were quantified by DAD-RP-HPLC. Results: The highest DPPH antioxidant potential expressed in mg TE/gDE were frequently measured in fractions from n-butyl alcohol i.e 2 (192.1 ± 0.3); 6 (181.0 ± 0.1) of P. carolinensis and in fraction 7 (188.1 ± 5.5) of P. rosea while for ORAC (mg TE/gDE) assay fraction 2 (543.0 ± 64.6) and 4 (501.4 ± 49.7) of P. carolinensis and 3 (401.3 ± 16.1) and 6 (401.3 ± 16.1) of P. rosea showed the best results. Some flavonoids and phenolic acids were also assayed; all of them showed highest Oxygen radical absorbance capacity values. Conclusion: We report the antioxidant potential of polar fractions, as well as of some pure phenolics responsible of the antioxidant potential. Some phenolics were identified and quantified for the first time in both species. Apparently, caffeoylquinic acid derivatives contribute more significant to the total antioxidant potential of the extracts. [less ▲]

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See detailAntioxidant Activity of Flavonoids Isolated From the Fruits of Xylopia parviflora (A. Rich.) Benth
Tchinda Tiabou, Alembert ULg; Agbor, GA; Tsala, DE et al

in International Journal of Pharmaceutical Sciences and Drug Research (2014), 6

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See detailPhytochemical analysis of Tetraclinis articula in relation to its vasorelaxant property.
zidane, Ahlam; Tits, Monique ULg; Angenot, Luc ULg et al

in Journal of Materials and Environmental Science (2014), 5(5), 1368-1375

Tetraclinis articulata (Cupressaceae), a traditional Moroccan herbal drug is used in oriental Morocco to treat diabetes and arterial hypertension. In a previous study we showed that the crude aqueous ... [more ▼]

Tetraclinis articulata (Cupressaceae), a traditional Moroccan herbal drug is used in oriental Morocco to treat diabetes and arterial hypertension. In a previous study we showed that the crude aqueous extract of T. articulata induces endotheliumdependent relaxation ... [less ▲]

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See detailAntioxidant Activity of Compounds Isolated from the Root Woods of Erythrina droogmansiana
Yaya, AJG; Feumba, RD; Emmanuel, T et al

in International Journal of Pharmaceutical Sciences and Drug Research (2014), 6(2), 160-163

The aim of this study was to isolate, to characterize secondary metabolites from methanolic extract of the root woods of Erythrina droogmansiana and to assess the antioxidant activity of the crude extract ... [more ▼]

The aim of this study was to isolate, to characterize secondary metabolites from methanolic extract of the root woods of Erythrina droogmansiana and to assess the antioxidant activity of the crude extract and isolated compounds. The phytochemical study led to the isolation of 3-(3’,4’-methelenedioxyphenyl)-2,3-epoxypropanol (1), asperphenamate (2) and three flavonoids namely genistein, diadzein and 4’,5,7-trihydroxy-8-prenylisoflavone. These compounds were characterized using their 1H NMR, 13C NMR, HMBC, HSQC, COSY, mass spectral and the literature. To evaluate antioxidant activity of crude extract and isolated compounds, the radical scavenging (DPPH) and Ferric Reducing Ability Power (FRAP) were performed using ascorbic acid as standard. Compounds 1 and 2 showed moderate radical scavenging potential with IC50 value of 3.14 and 3.31 mg/ml respectively, and moderate reducing power ability with value of 0.14±0.01 mgAAE/mg and 0.21±0.01 mgAAE/mg respectively. The more active compound was genistein (3) with IC50 value of 1.96 mg/ml for the DPPH radical scavenging potential and 0.24±0.02 mgAAE/mg for its ability to reduce iron. [less ▲]

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See detailIn Vitro and In Vivo Antiplasmodial Activity of Three Rwandan Medicinal Plants and Identification of Their Active Compounds
Muganga, Raymond; Angenot, Luc ULg; Tits, Monique ULg et al

in Planta Medica (2014), 80(6), 482-489

In our previous study, we reported the interesting in vitro antiplasmodial activity of some Rwandan plant extracts. This gave rise to the need for these extracts to also be evaluated in vivo and to ... [more ▼]

In our previous study, we reported the interesting in vitro antiplasmodial activity of some Rwandan plant extracts. This gave rise to the need for these extracts to also be evaluated in vivo and to identify the compounds responsible for their antiplasmodial activity. The aim of our study was, on the one hand, to evaluate the antiplasmodial activity in vivo and the safety of the selected Rwandan medicinal plants used in the treatment of malaria, with the objective of promoting the development of improved traditional medicines and, on the other hand, to identify the active ingredients in the plants. Plant extracts were selected according to their selectivity index. The in vivo antiplasmodial activity of aqueous, methanolic, and dichloromethane extracts was then evaluated using the classical 4-day suppressive test on Plasmodium berghei infected mice. The activity of the plant extracts was estimated by measuring the percentage of parasitemia reduction, and the survival of the experimental animals was recorded. A bioguided fractionation was performed for the most promising plants, in terms of antiplasmodial activity, in order to isolate active compounds identified by means of spectroscopic and spectrometric methods. The highest level of antiplasmodial activity was observed with the methanolic extract of Fuerstia africana (> 70 %) on days 4 and 7 post-treatment after intraperitoneal injection and on day 7 using oral administration. After oral administration, the level of parasitemia reduction observed on day 4 post-infection was 44 % and 37 % with the aqueous extract of Terminalia mollis and Zanthoxylum chalybeum, respectively. However, the Z. chalybeum extract presented a high level of toxicity after intraperitoneal injection, with no animals surviving on day 1 post-treatment. F. africana, on the other hand, was safer with 40 % mouse survival on day 20 post-treatment. Ferruginol is already known as the active ingredient in F. Africana, and ellagic acid (IC50 = 175 ng/mL) and nitidine (IC50 = 77.5 ng/mL) were identified as the main active constituents of T. mollis and Z. chalybeum, respectively. F. africana presented very promising antiplasmodial activity in vivo. Although most of the plants tested showed some level of antiplasmodial activity, some of these plants may be toxic. This study revealed for the first time the role of ellagic acid and nitidine as the main antimalarial compounds in T. mollis and Z. chalybeum, respectively. [less ▲]

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See detailStrychnobaillonine, an Unsymmetrical Bisindole Alkaloid with an Unprecedented Skeleton from Strychnos icaja Baill. Roots
Tchinda Tiabou, Alembert ULg; Jansen, Olivia ULg; Nyemb, Jean-Noel et al

in Journal of Natural Products (2014), 77

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See detailChemical composition, cytotoxicity and in vitro antitrypanosomal and antiplasmodial activity of the essential oils of four Cymbopogon species from Benin.
Kpoviessi, Salome; Bero, Joanne; Agbani, Pierre et al

in Journal of ethnopharmacology (2014), 151

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of ... [more ▼]

ETHNOPHARMACOLOGICAL RELEVANCE: Cymbopogon species are largely used in folk medicine for the treatment of many diseases some of which related to parasitical diseases as fevers and headaches. As part of our research on antiparasitic essential oils from Beninese plants, we decided to evaluate the in vitro antiplasmodial and antitrypanosomal activities of essential oils of four Cymbopogon species used in traditional medicine as well as their cytotoxicity. MATERIALS AND METHODS: The essential oils of four Cymbopogon species Cymbopogon citratus (I), Cymbopogon giganteus (II), Cymbopogon nardus (III) and Cymbopogon schoenantus (IV) from Benin obtained by hydrodistillation were analysed by GC/MS and GC/FID and were tested in vitro against Trypanosoma brucei brucei and Plasmodium falciparum respectively for antitrypanosomal and antiplasmodial activities. Cytotoxicity was evaluated in vitro against Chinese Hamster Ovary (CHO) cells and the human non cancer fibroblast cell line (WI38) through MTT assay to evaluate the selectivity. RESULTS: All tested oils showed a strong antitrypanosomal activity with a good selectivity. Sample II was the most active against Trypanosoma brucei brucei and could be considered as a good candidate. It was less active against Plasmodium falciparum. Samples II, III and IV had low or no cytotoxicity, but the essential oil of Cymbopogon citraus (I), was toxic against CHO cells and moderately toxic against WI38 cells and needs further toxicological studies. Sample I (29 compounds) was characterised by the presence as main constituents of geranial, neral, beta-pinene and cis-geraniol; sample II (53 compounds) by the presence of trans-p-mentha-1(7),8-dien-2-ol, trans-carveol, trans-p-mentha-2,8-dienol, cis-p-mentha-2,8-dienol, cis-p-mentha-1(7),8-dien-2-ol, limonene, cis-carveol and cis-carvone; sample III (28 compounds) by beta-citronellal, nerol, beta-citronellol, elemol and limonene and sample IV (41 compounds) by piperitone, (+)-2-carene, limonene, elemol and beta-eudesmol. CONCLUSIONS: Our study shows that essential oils of Cymbopogon genus can be a good source of antitrypanosomal agents. This is the first report on the activity of these essential oils against Trypanosoma brucei brucei, Plasmodium falciparum and analysis of their cytotoxicity. [less ▲]

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See detailPhysicochemical properties of lipids extracted from Tenebrio molitor larvae
Danthine, Sabine ULg; Blecker, Christophe ULg; Paul, Aman ULg et al

Poster (2013, December)

Objectives: To determine the physicochemical properties of the oil obtained from Tenebrio molitor Larvae and explore its potential as edible oil. Methodology: Oils obtained from five batches of Tenebrio ... [more ▼]

Objectives: To determine the physicochemical properties of the oil obtained from Tenebrio molitor Larvae and explore its potential as edible oil. Methodology: Oils obtained from five batches of Tenebrio molitor Larvae were investigated. Among the samples, three were produced directly in the lab (3 different productions) and 2 were purchased from a local supplier. In addition to the total lipid content (solvent extraction), both FA (GC) and TAG (HPLC) profiles were determined. Thermal properties by DSC were also estimated. Results and conclusion: The fresh Larvae from the lab contained 52% of total proteins (% dry matter). Their total fat content was around 36% (% dry matter). The commercial samples contained more proteins, but less fat: around 58% of total proteins and 30% of total fat (% dry matter). All the extracted oils contained high amount of unsaturated fatty acids. However, the chemical composition and the thermal properties of the samples varied according to their origin. The level and quality of lipid content offer potential as a substitute of oilseeds. [less ▲]

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See detailGrasshoppers: Food Security & Nutrition
Paul, Aman ULg; Danthine, Sabine ULg; Frederich, Michel ULg et al

Scientific conference (2013, December)

Rising economies and rapid urbanization in developing countries, particularly in Asia, are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with ... [more ▼]

Rising economies and rapid urbanization in developing countries, particularly in Asia, are creating shifts in the composition of global food demand, so it is necessary to explore new sources of food with better nutritional profile. Among the alternative food that exists are the grasshoppers, about 80 species of which are consumed worldwide. Grasshoppers are not only rich source of proteins and lipids but also some important minor component like vitamins and minerals. Apart from being nutritionally superior to most conventional meats their production results in lower emission of greenhouse gases & ammonia, risk of zoonotic infections in humans is much lower, water requirement for production is much less and have higher feed conversion ratio. Edible species of grasshopper in Belgium were identified, attempts were made for the lab rearing of meadow grasshopper (Chorthippus parallelus) and fat as well as protein contents of meadow grasshopper (Chorthippus parallelus) & long winged conehead (Conocephalus discolor) were investigated. [less ▲]

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See detailSome natural products from aerial parts of Scrophularia imerethica
Getia, M; Mshvildadze, V; Dekanosidze, G et al

Poster (2013, June 17)

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See detailLes substances naturelles dans la lutte contre le paludisme
Frederich, Michel ULg

Scientific conference (2013, May 25)

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See detailFalsification des médicaments: mythe ou réalité ?
Marini Djang'Eing'A, Roland ULg; Fillet, Marianne ULg; Vancauwenberghe, Roy et al

Conference (2013, April 24)

La santé publique est de nos jours minée par la problématique des médicaments falsifiés ou de qualité inférieure, avec plusieurs conséquences sanitaires, économiques voire professionnelles. On estime à 7 ... [more ▼]

La santé publique est de nos jours minée par la problématique des médicaments falsifiés ou de qualité inférieure, avec plusieurs conséquences sanitaires, économiques voire professionnelles. On estime à 7% la part du marché pharmaceutique mondial que représenterait ce fléau; l’Afrique, l’Asie et de nombreux pays d'Amérique latine étant les régions les plus touchées avec plus de 30% de médicaments falsifiés. D’après l'OMS, plus de 50% des médicaments achetés à partir des sites internet illégaux sont contrefaits, annihilant très fortement les chances de succès thérapeutique. Ces médicaments viennent dans la plupart des cas des pays asiatiques et de l’Eurasie. Le trafic de faux médicaments est un crime contre l'humanité qui représente environ 50 milliards de dollars par an (10-15 % de plus que le marché de la drogue). Au travers de deux leçons, la situation de la falsification des médicaments sera présentée au grand public dans le but de le sensibiliser à ce fléau. La première leçon présentera la situation en Europe avec un accent sur la Belgique. La problématique du droit à la propriété intellectuelle et de l’encadrement législatif sera abordée, ainsi que la falsification des médicaments modernes et des phytomédicaments, ces derniers étant utilisés par plus de 40% de la population en Europe et aux Etats-Unis. Dans la seconde leçon sera abordée la situation vécue en Afrique. L’approvisionnement en médicaments de qualité par le partage de l’information sera présenté ainsi que les moyens analytiques à la disposition de ce continent pour combattre ce fléau. Des membres du Département de Pharmacie de l’Université de Liège, de l’Agence Fédérale des Médicaments et des Produits de Santé ainsi que du programme QUAMED (Quality Medicines for All) feront partager leur expérience sur cette question d’une brûlante actualité.  [less ▲]

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See detailUnusual Amino Acids and Monofluoroacetate from Dichapetalum michelsonii (Umutambasha), a Toxic Plant from Rwanda
Esters, Virginie ULg; Karangwa, Charles; Tits, Monique ULg et al

in Planta Medica (2013), 79

In the course of our investigations on Umutambasha in order to identify its convulsant principles, small quantities of monofluoroacetate were observed in stem bark, leaves, and fruits of this plant newly ... [more ▼]

In the course of our investigations on Umutambasha in order to identify its convulsant principles, small quantities of monofluoroacetate were observed in stem bark, leaves, and fruits of this plant newly identified as Dichapetalum michelsonii Hauman. Conclusive evidence for a monofluoroacetate presence came from its isolation from the freeze-dried extract of stem bark. Three free unusual amino acids, named N-methyl-α-alanine, N-methyl-β-alanine, and 2,7-diaminooctan-1,8-dioic acid, described for the first time in a plant, and known trigonelline were also isolated from the stem bark of D. michelsonii. Structure elucidations were mainly achieved by spectroscopic methods (1H-NMR, 2D-NMR, MS) and by comparison with authentic references. These unusual amino acids were detected by a fast, reliable TLC analysis in all our batches of Umutambasha, suggesting that they could be used for identification purposes in case of human or livestock intoxications. Finally, EEG recordings and behavioural observations performed in mice suggested that the convulsive patterns produced by Umutambasha are the consequence of monofluoroacetate presence in D. michelsonii. [less ▲]

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