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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 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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See detailL'usage de substances psychotropes ( en particulier l'ayahuasca et l'iboga) dans le marché du spirituel
Angenot, Luc ULg; Constant Eric; Lison, Dominique

Report (2013)

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See detailPhenolic acid-rich extract of sweet basil restores cholesterol and triglycerides metabolism in high fat diet-fed mice: A comparison with fenofibrate
Harnafi, H.; Ramchoun, M.; Tits, Monique ULg et al

in Biomedicine & Preventive Nutrition (2013), 3(4), 393-397

Many spices are often added to foods as additives to enhance organoleptic qualities, such as flavor, aroma and color. Sweet basil (Ocimum basilicum L.) family of Lamiaceae is widely used in cooking for ... [more ▼]

Many spices are often added to foods as additives to enhance organoleptic qualities, such as flavor, aroma and color. Sweet basil (Ocimum basilicum L.) family of Lamiaceae is widely used in cooking for its culinary attributes. In this study, we aimed at the investigation of the hypocholesterolemic and hypotriglyceridemic activities of the basil phenolic acid-rich extract in high fat diet-induced hyperlipemic mice. Hyperlipemia was developed by a high fat diet containing cholesterol, lard and cholic acid. At the beginning of the experiment, animals were divided into three groups, one of them served as normolipidemic control group (NCG), the second hyperlipidemic control group (HCG) and the third basil-treated group (BTG). After 5 weeks of treatment, basil phenolic acid-rich extract significantly decreased plasma total cholesterol, triglycerides and LDL-cholesterol (-42%,-42% and -86%, respectively, P < 0.001). However, HDL-cholesterol was increased (+79%, P < 0.001). The extract reduced the atherogenic index and LDL/HDL-C ratio (-88% and -94%, respectively, P < 0.001). The reductions of liver total cholesterol and triglycerides were of -50% (P < 0.01) and -58% (P < 0.01), respectively. The hypolipemic effect of the phenolic acid-rich extract is comparable to that exerted by fenofibrate. This drug significantly reduced plasma total cholesterol, triglycerides and LDL-cholesterol (-25.5%, -51%, and -83.5%, respectively, P < 0.001) and increased plasma HDL-cholesterol (+136%, P < 0.001). On the other hand, fenofibrate significantly decreased atherogenic index and LDL/HDL-cholesterol ratio (-91% and -93%, respectively, P < 0.001). The fenofibrate decreased hepatic total cholesterol by 59.5% and triglycerides by 72%, respectively (P < 0.01). HPLC analysis led to identify four major compounds: caftaric acid, cafeic acid, chicoric acid and rosmarinic acid. In conclusion, the Sweet basil contains phenolic products that are able to lower hyperlipidemia and prevent atherosclerosis. © 2013 Elsevier Masson SAS. All rights reserved. [less ▲]

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See detailIsolation, pharmacological activity and structure determination of physalin B and 5[beta],6[beta]-ep­oxy­physalin B isolated from Congolese Physalis angulata L.
Mangwala Kimpende, P.; Lusakibanza, M.; Mesia, K. et al

in Acta Crystallographica Section C: Crystal Structure Communications (2013), C69

Physalis angulata L., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, (X) and (Y), were isolated from a ... [more ▼]

Physalis angulata L., an annual herb from the Solanaceae family, is widely used in popular medicine in tropical countries to treat a variety of diseases. Two products, (X) and (Y), were isolated from a crude CH2Cl2 extract of dried Congolese Physalis angulata L. plants and crystallized from acetone for structure elucidation. Compound (X) corresponds to a physalin B dimer acetone solvate hydrate (2C28H30O9·C3H6O·0.22H2O), while compound (Y) crystallizes as a mixed crystal containing two physalin B mol­ecules which overlap with 5[beta],6[beta]-ep­oxy­physalin B, also known as physalin F, and one acetone mol­ecule in the asymmetric unit (1.332C28H30O9·0.668C28H30O10·C3H6O). Anti­­plasmodial activity, cytotoxic activity and selectivity indices were determined for crude extracts and the two isolated products (X) and (Y). [less ▲]

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See detailIdentification and determination of alkaloids in Fumaria Species from Romania
Paltinean, Ramona; Toju, A; Wauters, Jean-Noël ULg et al

in Digest Journal of Nanomaterials & Biostructures [=DJNB] (2013), 8(2), 817-824

Four Fumaria species (F. vaillantii Loisel, F. parviflora Lam., F. rostellata Knaf and F. jankae Hausskn.) were analysed in order to determine the presence of the isoquinoline alkaloids allocryptopine ... [more ▼]

Four Fumaria species (F. vaillantii Loisel, F. parviflora Lam., F. rostellata Knaf and F. jankae Hausskn.) were analysed in order to determine the presence of the isoquinoline alkaloids allocryptopine, chelidonine, protopine, bicuculline, sanguinarine, cheleritrine, stylopine, and hydrastine through an HPLC-DAD method. Protopine and sanguinarine were present in all extracts. Bicuculline and stylopine were found in F. vaillantii and F. parviflora, whilst chelidonine was identified only in F. vaillantii and hydrastine in F. jankae, so they represent potential taxonomic markers that differentiate the four plants. The richest species in isoquinoline alkaloids was F. parviflora. Our study showed significant differences between the four Fumaria species, both qualitative and quantitative. [less ▲]

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See detailComparative morphological studies on some species of the genus Fumaria
Paltinean, Ramona; Wauters, Jean-Noël ULg; Tits, Monique ULg et al

in Farmacia (2013), 61(2), 371-377

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See detailDimeric bisindole alkaloids from the stem bark of Strychnos nux-vomica L.
Jonville, Marie-Caroline ULg; Dive, Georges ULg; Angenot, Luc ULg et al

in Phytochemistry (2013), 87

Strychnos nux-vomica L. (Loganiaceae) is famous for its monomeric alkaloid content, such as strychnine, a convulsant poison. The stem bark of the tree is traditionally used to treat intermittent fever in ... [more ▼]

Strychnos nux-vomica L. (Loganiaceae) is famous for its monomeric alkaloid content, such as strychnine, a convulsant poison. The stem bark of the tree is traditionally used to treat intermittent fever in South East Asia. In various studies, it appeared that dimeric indolo-monoterpenic alkaloids possess a promising activity on Plasmodium falciparum. Three bisindolomonoterpenic alkaloids together with strychnochrysine, previously identified in the root bark of S. nux-vomica, were isolated from the stem bark. The structures of these compounds were established using NMR spectroscopy and mass spectrometry. Stereochemistry of the compounds was confirmed by molecular modelling. This then allowed the structural determination of strychnoflavine, a coloured bisindole alkaloid previously isolated from the root bark of the tree. Moreover, the conformational inversion in alkaloids possessing an ether bond in the strychnane moiety could be easily predicted by specific δ 13C NMR values. These longicaudatine-type alkaloids were found to display in vitro antiplasmodial activity against a chloroquine resistant strain and a chloroquine sensitive strain. The most interesting was strychnochrysine showing an IC 50 value at around 10 μM. © 2012 Elsevier Ltd. All rights reserved. [less ▲]

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See detailPotential anticancer activity of young Carpinus betulus leaves
Cieckiewicz, Ewa ULg; Angenot, Luc ULg; Gras, T et al

in Planta Medica (2012, August), 78(11), 1178

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See detailPotential anticancer activity of young Carpinus betulus leaves.
Cieckiewicz, Ewa ULg; Angenot, Luc ULg; Gras, T. et al

in Phytomedicine : International Journal of Phytotherapy and Phytopharmacology (2012), 19(3/4), 278-284

As part of our continuing research for anticancer compounds from the Walloon Region forest, EtOAc extract from Carpinus betulus leaves was phytochemically studied, leading to the bioguided isolation of ... [more ▼]

As part of our continuing research for anticancer compounds from the Walloon Region forest, EtOAc extract from Carpinus betulus leaves was phytochemically studied, leading to the bioguided isolation of pheophorbide a, which is responsible of anticancer properties of C. betulus young leaves. This compound was identified using nuclear magnetic resonance and mass spectrophotometric data and comparison with a commercial standard. Evaluation of the growth inhibitory activities of pheophorbide a using MTT colorimetric assay and phase-contrast microscopy in various human cancer cell lines confirmed the photoactivable properties of this compound. Our research showed, for the first time, the presence of pheophorbide a, a chlorophyll derived compound, which we quantified in high quantities in young leaves of C. betulus. This is in contrast with the literature which generally describes pheophorbide a as a catabolic product of chlorophyll, then preferentially present in old leaves. [less ▲]

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See detailEloge académique du professeur Charles-Léon Lapière
Angenot, Luc ULg

in Bulletin et Mémoires de l'Académie Royale de Médecine de Belgique (2012), 167(1), 21-27

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See detailAlkaloids from the stem bark of Strychnos icaja
Tchinda Tiabou, Alembert ULg; Tamze, Victorine; Ngono, Annie R N et al

in Phytochemistry Letters (2012), 5(1), 108-113

A comprehensive phytochemical study of the stem bark of Strychnos icaja was done for the first time and led to the isolation of two new monoindole alkaloids 15-hydroxyvomicine (1) and 12-methoxyicajine (2 ... [more ▼]

A comprehensive phytochemical study of the stem bark of Strychnos icaja was done for the first time and led to the isolation of two new monoindole alkaloids 15-hydroxyvomicine (1) and 12-methoxyicajine (2) along with 13 known alkaloids: the monoindoles N-methyl-sec-iso-pseudostrychnine (3), vomicine (4), icajine (5), 19,20-α-epoxy-12-methoxyicajine (6), 19,20-α-epoxy-12,15-dihydroxy-11-methoxyicajine (7), 19,20-α-epoxy-15-hydroxynovacine (8), 15-hydroxyicajine (9), 12-hydroxystrychnine (10), strychnine (11) and the tertiary bisindoles sungucine (12), isosungucine (13), strychnogucine C (14) and bisnordihydrotoxiferine (15). Apart from 10 and 11, the other alkaloids were isolated for the first time from the stem bark of this plant. The hemisynthetic derivative, Nb-chloromethosungucine (16) and the previously reported synthetic compound 3 were isolated from a natural source for the first time. Fractions and some isolated compounds were tested against the chloroquine-sensitive 3D7 strain of Plasmodium falciparum. The bisindole alkaloids were most active with IC50 ranging from 0.72 to 3.41 μg/ml whilst the monomers 1 and 3 were slightly active (IC50 39.92 and 40.27 μg/ml respectively) and 6 inactive. The structures of the compounds were determined based on the analysis of their spectral data. The full 1H and 13C NMR data of compounds 3, 6 and 7 are also reported in the present work for the first time. [less ▲]

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See detailAnti-plasmodial activity of Dicoma tomentosa (Asteraceae) and identification of urospermal A-15- O-acetate as the main active compound.
Jansen, Olivia ULg; Tits, Monique ULg; Angenot, Luc ULg et al

in Malaria Journal (2012), 11(1), 2891-9

ABSTRACT: BACKGROUND: Natural products could play an important role in the challenge to discover new anti-malarial drugs. In a previous study, Dicoma tomentosa (Asteraceae) was selected for its promising ... [more ▼]

ABSTRACT: BACKGROUND: Natural products could play an important role in the challenge to discover new anti-malarial drugs. In a previous study, Dicoma tomentosa (Asteraceae) was selected for its promising anti-plasmodial activity after a preliminary screening of several plants traditionally used in Burkina Faso to treat malaria. The aim of the present study was to further investigate the antiplasmodial properties of this plant and to isolate the active anti-plasmodial compounds. METHODS: Eight crude extracts obtained from D. tomentosa whole plant were tested in vitro against two Plasmodium falciparum strains (3D7 and W2) using the p-LDH assay (colorimetric method). The Peters' four-days suppressive test model (Plasmodium berghei-infected mice) was used to evaluate the in vivo anti-plasmodial activity. An in vitro bioguided fractionation was undertaken on a dichloromethane extract, using preparative HPLC and TLC techniques. The identity of the pure compound was assessed using UV, MS and NMR spectroscopic analysis. In vitro cytotoxicity against WI38 human fibroblasts (WST-1 assay) and haemolytic activity were also evaluated for extracts and pure compounds in order to check selectivity. RESULTS: The best in vitro anti-plasmodial results were obtained with the dichloromethane, diethylether, ethylacetate and methanol extracts, which exhibited a high activity (IC50 [less than or equal to] 5 mug/ml). Hot water and hydroethanolic extracts also showed a good activity (IC50 [less than or equal to] 15 mug/ml), which confirmed the traditional use and the promising anti-malarial potential of the plant. The activity was also confirmed in vivo for all tested extracts. However, most of the active extracts also exhibited cytotoxic activity, but no extract was found to display any haemolytic activity. The bioguided fractionation process allowed to isolate and identify a sesquiterpene lactone (urospermal A-15-O-acetate) as the major anti-plasmodial compound of the plant (IC50 < 1 mug/ml against both 3D7 and W2 strains). This was also found to be the main cytotoxic compound (SI =3.3). While this melampolide has already been described in the plant, this paper is the first report on the biological properties of this compound. CONCLUSIONS: The present study highlighted the very promising anti-plasmodial activity of D. tomentosa and enabled to identify its main active compound, urospermal A-15-O-acetate. The high antiplasmodial activity of this compound merits further study about its anti-plasmodial mechanism of action. The active extracts of D. tomentosa, as well as urospermal A 15-Oacetate, displayed only a moderate selectivity, and further studies are needed to assess the safety of the use of the plant by the local population. [less ▲]

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See detailLes effets toxiques en aromathérapie
Angenot, Luc ULg

Scientific conference (2012)

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See detailLes Huiles Essentielles et l'Aromathérapie
Angenot, Luc ULg

Learning material (2012)

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See detailRotenoid content and in vitro acaricidal activity of Tephrosia vogelii leaf extract on the tick Rhipicephalus appendiculatus
Kalume; Losson, Bertrand ULg; Angenot, Luc ULg et al

in Veterinary Parasitology (2012), 190(1-2), 204-209

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See detailPolyphenol Content and Modulatory Activities of Some Tropical Dietary Plant Extracts on the Oxidant Activities of Neutrophils and Myeloperoxidase
Tsumbu, César Ndele ULg; Deby-Dupont, Ginette; Tits, Monique ULg et al

in International Journal of Molecular Sciences (2012), 13(1), 628-650

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See detailAnalysis of Passion Fruit Rinds (Passiflora edulis): Isoorientin Quantification by HPTLC and Evaluation of Antioxidant ( Radical Scavenging) Capacity
Zeraik, Maria Luiza; Yariwake, Janete; Wauters, Jean-Noël ULg et al

in Quimica Nova (2012), 35(3), 541-545

The content of isoorientin in passion fruit rinds ( Passiflora edulis fo. flavicarpa O.Degener) was determined by HPTLC with densitometric analysis. The results revealed a higher amount of isoorientin in ... [more ▼]

The content of isoorientin in passion fruit rinds ( Passiflora edulis fo. flavicarpa O.Degener) was determined by HPTLC with densitometric analysis. The results revealed a higher amount of isoorientin in healthy rinds of Passiflora than in rinds with typical symptoms of PWV ( Passion fruit woodliness virus). the HPTLC data ,allied to assays of radical scavenging activity, suggest the potential of P. edulis rinds as a natural source of flavonoids or as a possible functional food. [less ▲]

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