References of "Frederich, Michel"
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See detailFlavonoid Analysis and Antioxidant Activities of the Bryonia alba L. Aerial Parts
Ielciu, Irina; Frederich, Michel ULiege; Hanganu, Daniela et al

in Antioxidants (2019), 8(4 108),

Bryonia alba L. is the only Bryonia species found in Romanian flora, being known as a remedy for inflammatory pathologies or for its hepatoprotective and adaptogen activities. The present investigation ... [more ▼]

Bryonia alba L. is the only Bryonia species found in Romanian flora, being known as a remedy for inflammatory pathologies or for its hepatoprotective and adaptogen activities. The present investigation studied the flavonoid composition and antioxidant activities of the aerial parts of this species. Flavonoid profile was evaluated by HPLC coupled with Diode Array Detection (DAD), while antioxidant capacity was assessed by various methods, testing different antioxidant mechanisms: DPPH (2,2-diphenyl-1-picrylhydrazyl), CUPRAC (cupric reducing antioxidant capacity), FRAP (ferric reducing ability of plasma), TEAC (Trolox equivalent antioxidant capacity), EPR (electron paramagnetic resonance method) and SNPAC (silver nanoparticles antioxidant capacity). Cytotoxicity was tested on human cancerous and healthy cell lines. Anti-plasmodial tests were performed on two strains of Plasmodium falciparum. Whole organism toxicity was assessed on zebrafish larvae. The HPLC-DAD analysis proved the presence of lutonarin, saponarin, isoorientin, and isovitexin as the major flavonoids in the composition of tested samples. Significant results were obtained for all antioxidant capacity assays. The cytotoxicity tests proved the absence of cellular and parasitic toxicity and these results were confirmed by the lack of toxicity on the zebrafish larvae model. This study proves a promising potential of the aerial parts of Bryonia alba L. as antioxidant agents. [less ▲]

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See detailAntiplasmodial Diterpenoids from Psiadia arguta.
Mahadeo, Keshika; Herbette, Gaetan; Grondin, Isabelle et al

in Journal of natural products (2019)

An ethyl acetate extract of Psiadia arguta leaves showed in vitro antiplasmodial activity against Plasmodium falciparum with IC50 values of 12.3 +/- 2.4 mug/mL (3D7 strain) and 13.5 +/- 3.4 mug/mL (W2 ... [more ▼]

An ethyl acetate extract of Psiadia arguta leaves showed in vitro antiplasmodial activity against Plasmodium falciparum with IC50 values of 12.3 +/- 2.4 mug/mL (3D7 strain) and 13.5 +/- 3.4 mug/mL (W2 strain). Phytochemical investigation led to the isolation and characterization of 16 compounds including four new diterpenoids: labdan-8alpha-ol-15-yl-(formate) (1), labdan-8alpha-ol-15-yl-(2-methylbutanoate) (2), labdan-8alpha-ol-15-yl-(3-methylpentanoate) (3), and labdan-8alpha-ol-15-yl-(labdanolate) (4). The latter compounds were characterized by spectroscopic methods (1D and 2D NMR, HRMS, and IR). The in vitro antiplasmodial activities of all compounds were evaluated. The known compounds labdan-13( E)-en-8alpha-ol-15-yl acetate (5), labdan-8alpha-ol-15-yl acetate (6), 13- epi-sclareol (7), labdan-13( E)-ene-8alpha,15-diol (8), and (8 R,13 S)-labdane-8alpha,15-diol (9) exhibited antiplasmodial effects, with IC50 values of 29.1, 33.2, 35.0, 36.6, and 22.2 muM, respectively. [less ▲]

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See detailCollected mass spectrometry data on monoterpene indole alkaloids from natural product chemistry research.
Fox Ramos, Alexander E.; Le Pogam, Pierre; Fox Alcover, Charlotte et al

in Scientific Data (2019), 6(1), 15

This Data Descriptor announces the submission to public repositories of the monoterpene indole alkaloid database (MIADB), a cumulative collection of 172 tandem mass spectrometry (MS/MS) spectra from ... [more ▼]

This Data Descriptor announces the submission to public repositories of the monoterpene indole alkaloid database (MIADB), a cumulative collection of 172 tandem mass spectrometry (MS/MS) spectra from multiple research projects conducted in eight natural product chemistry laboratories since the 1960s. All data have been annotated and organized to promote reuse by the community. Being a unique collection of these complex natural products, these data can be used to guide the dereplication and targeting of new related monoterpene indole alkaloids within complex mixtures when applying computer-based approaches, such as molecular networking. Each spectrum has its own accession number from CCMSLIB00004679916 to CCMSLIB00004680087 on the GNPS. The MIADB is available for download from MetaboLights under the identifier: MTBLS142 ( https://www.ebi.ac.uk/metabolights/MTBLS142 ). [less ▲]

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See detailNew Antimalarial and Antimicrobial Tryptamine Derivatives from the Marine Sponge Fascaplysinopsis reticulata
Campos, P.-E.; Pichon, E.; Moriou, C. et al

in Marine Drugs (2019), 17(3), 167

Chemical study of the CH₂Cl₂-MeOH (1:1) extract of the sponge Fascaplysinopsis reticulata collected in Mayotte highlighted three new tryptophan derived alkaloids, 6,6'-bis-(debromo)-gelliusine F (1), 6 ... [more ▼]

Chemical study of the CH₂Cl₂-MeOH (1:1) extract of the sponge Fascaplysinopsis reticulata collected in Mayotte highlighted three new tryptophan derived alkaloids, 6,6'-bis-(debromo)-gelliusine F (1), 6-bromo-8,1'-dihydro-isoplysin A (2) and 5,6-dibromo-8,1'-dihydro-isoplysin A (3), along with the synthetically known 8-oxo-tryptamine (4) and the three known molecules from the same family, tryptamine (5), (E)-6-bromo-2'-demethyl-3'-N-methylaplysinopsin (6) and (Z)-6-bromo-2'-demethyl-3'-N-methylaplysinopsin (7). Their structures were elucidated by 1D and 2D NMR spectra and HRESIMS data. All compounds were evaluated for their antimicrobial and their antiplasmodial activities. Regarding antimicrobial activities, the best compounds are (2) and (3), with minimum inhibitory concentration (MIC) of 0.01 and 1 µg/mL, respectively, towards Vibrio natrigens, and (5), with MIC values of 1 µg/mL towards Vibrio carchariae. In addition the known 8-oxo-tryptamine (4) and the mixture of the (E)-6-bromo-2'-demethyl-3'-N-methylaplysinopsin (6) and (Z)-6-bromo-2'-demethyl-3'-N-methylaplysinopsin (7) showed moderate antiplasmodial activity against Plasmodium falciparum with IC50 values of 8.8 and 8.0 µg/mL, respectively. [less ▲]

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See detailChenopodium ambrosioides induces an endothelium-dependent relaxation of rat isolated aorta
Assaidi, Asmae; Dib, Ikram; Tits, Monique ULiege et al

in Journal of Integrative Medicine (2019), 17(2), 115-124

Objective This study aims to evaluate the vasodilatory effect of Chenopodium ambrosioides on the isolated rat aorta, and to explore its mechanism of action. Methods The vasorelaxant effect and the mode of ... [more ▼]

Objective This study aims to evaluate the vasodilatory effect of Chenopodium ambrosioides on the isolated rat aorta, and to explore its mechanism of action. Methods The vasorelaxant effect and the mode of action of various extracts from the leaves of C. ambrosioides were evaluated on thoracic aortic rings isolated from Wistar rats. In addition, ethyl acetate and methanol fractions were analyzed, using thin-layer chromatography and high-performance liquid chromatography techniques, for their polyphenolic content. Results The various active extracts of C. ambrosioides at four concentrations (10−3, 10−2, 10−1 and 1 mg/mL) relaxed the contraction elicited by phenylephrine, in a concentration-dependent manner. This effect seems to be endothelium-dependent, since the vasodilatory effect was entirely absent in denuded aortic rings. The vasorelaxant effect of the methanol fraction (MF) of C. ambrosioides at 1 mg/mL was also inhibited by atropine and tetraethylammonium. This effect remained unchanged by Nω-nitro-l-arginine methyl ester hydrochloride and glibenclamide. The preliminary phytochemical analysis showed that the leaves of C. ambrosioides are rich in phenolic and flavonoid derivatives. Conclusion These results suggest that the MF of C. ambrosioides produces an endothelium-dependent relaxation of the isolated rat aorta, which is thought to be mediated mainly through stimulation of the muscarinic receptors, and probably involving the opening of Ca2+-activated potassium channels. [less ▲]

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See detailAntileishmanial and cytotoxic activities of a new limonoid and a new phenyl alkene from the stem bark of Trichilia gilgiana (Meliaceae)
Kowa, Theodora K.; Tchokouaha, Lauve R. Y.; Cieckiewicz, Ewa ULiege et al

in Natural Product Research (2019), 0(0), 1-7

AbstractOne new limonoid, trigilgianin (1), one new phenyl alkene, epoxy gilgialkene (2), together with five known compounds: scopoletin (3), sitosteryl-6’-O-undecanoate-β-D-glucoside (4), sitosteryl-O-β ... [more ▼]

AbstractOne new limonoid, trigilgianin (1), one new phenyl alkene, epoxy gilgialkene (2), together with five known compounds: scopoletin (3), sitosteryl-6’-O-undecanoate-β-D-glucoside (4), sitosteryl-O-β-D-glucopyranoside (5), cinchonain A (6) and cinchonain B (7) were isolated from the stem bark of Trichilia gilgiana Harms. (Meliaceae). All compounds were isolated for the first time from this species. The structures were elucidated on the basis of spectral studies and by comparison of these data with those from the literature. Compounds 1, 2, 3, 6 and 7 were tested for in vitro antileishmanial activity against visceral leishmaniasis parasite Leishmania donovani and cytotoxicity against macrophage RAW 264.7 cell line. Compounds 1 and 3 showed the highest antileishmanial activity (IC50 values of 6.044 and 6.804 µg/mL, respectively) with low cytotoxicity (CC50 values of >200 and 47.47 µg/mL, respectively), while compound 2 was moderately active on L. donovani promastigotes (IC50 56.81 µg/mL). [less ▲]

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See detailPreparation of ellagic acid derivatives through a total synthesis approach to improve bioavailability.
Degotte, Gilles ULiege; Halleux, Annabelle; Hans, Aurore et al

Poster (2018, December)

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See detailAntiinflammatory and antileukemic-like activities of R01Yob, a medicinal plant of the rwandese pharmacopeia
Tomani, J; Nyirimigabo, Alain; Tchouate, O et al

Poster (2018, September 19)

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See detailA chemotaxonomic study of 11 species of the genus Psiadia endemic to La Reunion by 1H NMR and GC-MS based metabolomic approach
Mahadeo, Keshika; Grondin, Isabelle; Kodja, Hippolyte et al

Conference (2018, July 03)

The genus Psiadia Jacq. Ex. Willd. belongs to the Asteraceae family and includes more than 60 species, which are well represented in Madagascar and the Mascarene islands (La Réunion, Mauritius and ... [more ▼]

The genus Psiadia Jacq. Ex. Willd. belongs to the Asteraceae family and includes more than 60 species, which are well represented in Madagascar and the Mascarene islands (La Réunion, Mauritius and Rodrigues). Several Psiadia species are used traditionally to treat various ailments such as expectorant for treatment of bronchitis and asthma, colds and abdominal pains. According to litterature, only a few species have been studied for their chemical composition. In order to make a comprehensive study of the genus Psiadia in the Mascarene islands, a chemotaxonomic study was conducted on 11 species endemic to La Réunion. The aim was to identify chemical markers by a metabolomic approach using GC-MS and GC-FID for volatiles compounds and 1H NMR for non-volatiles compounds. The 11 studied species were collected from different locations and seasons in order to analyze the geographical or seasonal variability of the chemical profile of each species. This study led to two different classifications of the 11 species in terms of composition of volatiles and non-volatiles compounds. [less ▲]

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See detailAntimalarial and antitrypanosomal activity of strychnogucine B, a bisindole alkaloid from Strychnos icaja
Beaufay, Claire; Ledoux, Allison ULiege; Frederich, Michel ULiege et al

Poster (2018, July)

Strychnogucine B, a bisindole alkaloid isolated from Strychnos icaja (Loganiaceae), showed promising in vitro antiplasmodial properties (IC50 < 1μM) in previous studies [1, 2]. In order to obtain ... [more ▼]

Strychnogucine B, a bisindole alkaloid isolated from Strychnos icaja (Loganiaceae), showed promising in vitro antiplasmodial properties (IC50 < 1μM) in previous studies [1, 2]. In order to obtain sufficient quantities to further investigate its antiprotozoal activity, this compound was synthesized in four steps from (-)-strychnine [3]. The in vivo antimalarial activity of this semi-synthetic strychnogucine B (30 mg/kg/d, i.p) was determined in a Plasmodium berghei murine model using the Peters’ 4-day suppressive test. This alkaloid confirmed a promising antimalarial activity in vivo by suppressing the parasitaemia by almost 36 percent on day 5 and 60 percent on day 7 compared to vehicle treated mice. In addition to this interesting antiplasmodial potential, it also showed a moderate in vitro anti-trypanosomal activity (IC50 = 2.7μM) but no in vivo activity in an acute Trypanosoma brucei model. It was also inactive in vitro on Leishmania mexicana promastigotes. This study highlights the selective antiplasmodial efficacy of strychnogucine B and warrants further investigations to assess the potential of this alkaloid as new antimalarial lead compound. [less ▲]

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See detailAntiplasmodial activity of polyphenolic derivatives.
Degotte, Gilles ULiege; Alson, S.G.; Hans, Aurore ULiege et al

Poster (2018, June 12)

Despite the progress in the struggle against malaria, this parasitic disease remains a major public health problem with 216 million cases in 2016. The last advance was the development of artemisinin and ... [more ▼]

Despite the progress in the struggle against malaria, this parasitic disease remains a major public health problem with 216 million cases in 2016. The last advance was the development of artemisinin and its derivatives, near 15 years ago. These compounds are employed with success in combination with other antimalarial drugs and are now the recommended treatment by the World Health Organization. However, resistance of Plasmodium to these molecules appears and spreads over in Asia and Africa. Thus, the design of new antiplasmodial derivatives is imperative to hope the eradication of this infection. Polyphenolics compounds are well known to have multiple pharmacological activities such as antioxidant2, antitumor3, antimicrobial4 and antiplasmodial5. Regarding this last effect, the screening of caffeic acid (1) and its derivatives was performed in vitro and in vivo. These evaluations permitted to select ethyl caffeate (2) as the most potent derivatives against a 3D7 strain in culture. More interestingly, this ester was found active in mice with a stage specificity on the young trophozoites. The major interest of this molecule is that caffeic acid is widely distributed in plants and is considered non-toxic. Considering the results obtained with this first series of polyphenolic analogs and based on the known antimalarial activity of ellagic acid (3) in vitro and in vivo6, we currently investigate this widely distributed polyphenol as a scaffold for further pharmacomodulation. The new structures will be screened to determine their antiplasmodial effect. [less ▲]

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See detailL'ethnopharmacologie, à l'origine de nombreux médicaments : recherches dans le domaine des antipaludiques
Frederich, Michel ULiege

Conference (2018, June 07)

L’ethnopharmacologie, à l’origine de nombreux médicaments : recherches dans le domaine des antipaludiques Michel Frédérich, Professeur, Université de Liège L’ethnopharmacologie peut être définie comme « ... [more ▼]

L’ethnopharmacologie, à l’origine de nombreux médicaments : recherches dans le domaine des antipaludiques Michel Frédérich, Professeur, Université de Liège L’ethnopharmacologie peut être définie comme « l’étude scientifique interdisciplinaire des matières d’origine végétale, animale ou minérale, et des savoirs et pratiques s’y rattachant, que les sociétés mettent en œuvre à des fins thérapeutiques, curatives, préventives ou diagnostiques » (1). De nombreux médicaments indispensables aujourd’hui sont issus de ces connaissances traditionnelles : on peut citer par exemple l’universelle Aspirine®, provenant du saule, la quinine, médicament du paludisme, issu du quinquina Sud-Américain, ou encore l’artémisinine, dont la découverte a été récompensée du prix Nobel de Médecine en 2015. Aujourd’hui encore, selon l’OMS, 80% de la population mondiale a recourt, en première intention, aux plantes médicinales pour se soigner. Néanmoins, ces connaissances traditionnelles sont aujourd’hui menacées, que ce soit pour des raisons d’appauvrissement de la biodiversité, ou de déstructuration des sociétés et des connaissances traditionnelles. Le paludisme, provoqué par un parasite Apicomplexa du genre Plasmodium, transmis par des moustiques du genre Anopheles, a été responsable en 2016 de 445 000 décès dans le monde (2). La résistance des parasites aux médicaments disponibles et abordables est devenue un problème répandu dans les pays d’endémie, rendant encore plus nécessaire la recherche de nouveaux composés antipaludiques. Des résistances à l’artémisinine, médicament de référence, sont ainsi apparues dans différents pays asiatiques depuis quelques années (3). Selon Newmann et Cragg (4), plus de 60% des médicaments antiparasitaires découverts entre 1981 et 2014 sont des produits naturels (12,5%), des dérivés de produits naturels (31,3%) ou des médicaments synthétiques inspirés d’un pharmacophore naturel (18,8%). Plus particulièrement, les plantes constituent un réservoir potentiel de nouveaux médicaments antipaludiques (5, 6). La seconde partie de l’exposé décrira quelques travaux de recherche au sein du laboratoire de Pharmacognosie de l’Université de Liège, portant sur des plantes traditionnellement utilisées contre le paludisme (7). (1) Fleurentin, J. Traditions thérapeutiques et médecine de demain. 2011. Editions Ouest-France. (2) OMS, Rapport sur le paludisme dans le monde; 2017; p 280. (3) OMS. Status report on artemisinin and ACT resistance (April 2017); 2017, 11 pages. (4) Newman, D.J .; Cragg, G.M. J. Nat. Prod. 2016, 79, (3), 629-61. (5) Frédérich M., Tits M., Angenot L. , Trans. R. Soc. Trop. Med. Hyg. 2008, 102, 11-19. (6) Bero, J .; Frédérich, M.; Quetin-Leclercq, J. Pharm. Pharmacol.2009, 61, (11), 1401-1433. (7) Ledoux, A., St Gelais, A., (…), Frédérich, M. J. Nat. Prod. 2017, 80, 1750-1757. [less ▲]

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See detailCapillary electrophoresis, high-performance liquid chromatography, and thin-layer chromatography analyses of phenolic compounds from rapeseed plants and evaluation of their antioxidant activity.
Huang, Yang; Jansen, Olivia ULiege; Frederich, Michel ULiege et al

in Journal of Separation Science (2018)

Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and ... [more ▼]

Rapeseed plants, known for oil production, are also known to contain phenolic compounds such as phenolic acids and flavonoids, with potential antioxidant and anticancer activities. The separation and identification of 11 phenolic acids in rapeseed extracts (including leaves, flowers, Chinese seeds, Belgian seeds, and cake) by capillary electrophoresis were investigated. The results were compared with those obtained with high-performance liquid chromatography and thin-layer chromatography and showed that the capillary electrophoresis technique offers several advantages for the identification of phenolic compounds in various rapeseed extracts. The antioxidant activity of rapeseed extracts and reference compounds was evaluated using four different approaches, namely, 2,2'-azinobis- (3-ethylbenzohiazoline-6-sulfonic acid assay, free radical 2,2-diphenyl-1-picrylhydrazyl assay, electron paramagnetic resonance spectroscopy and the measurement of the total polyphenol content. The contents of total polyphenols in the tested extracts were ranging between 5.4 and 21.1% m/m and ranked as follows: Chinese seeds > Belgian seeds > Flowers > Cake > Leaves. [less ▲]

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