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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 detailSelective and reversible thiol-pegylation, an effective approach for purification and characterization of five fully active ficin (iso)forms from Ficus carica latex.
Azarkan, Mohamed; Matagne, André ULg; Wattiez, Ruddy et al

in Phytochemistry (2011), 72(14-15), 1718-31

The latex of Ficus carica constitutes an important source of many proteolytic components known under the general term of ficin (EC 3.4.22.3) which belongs to the cysteine proteases of the papain family ... [more ▼]

The latex of Ficus carica constitutes an important source of many proteolytic components known under the general term of ficin (EC 3.4.22.3) which belongs to the cysteine proteases of the papain family. So far, no data on the purification and characterization of individual forms of these proteases are available. An effective strategy was used to fractionate and purify to homogeneity five ficin forms, designated A, B, C, D1 and D2 according to their sequence of elution from a cation-exchange chromatographic support. Following rapid fractionation on a SP-Sepharose Fast Flow column, the different ficin forms were chemically modified by a specific and reversible monomethoxypolyethylene glycol (mPEG) reagent. In comparison with their un-derivatized counterparts, the mPEG-protein derivatives behaved differently on the ion-exchanger, allowing us for the first time to obtain five highly purified ficin molecular species titrating 1mol of thiol group per mole of enzyme. The purified ficins were characterized by de novo peptide sequencing and peptide mass fingerprinting analyzes, using mass spectrometry. Circular dichroism measurements indicated that all five ficins were highly structured, both in term of secondary and tertiary structure. Furthermore, analysis of far-UV CD spectra allowed calculation of their secondary structural content. Both these data and the molecular masses determined by MS reinforce the view that the enzymes belong to the family of papain-like proteases. The five ficin forms also displayed different specific amidase activities against small synthetic substrates like dl-BAPNA and Boc-Ala-Ala-Gly-pNA, suggesting some differences in their active site organization. Enzymatic activity of the five ficin forms was completely inhibited by specific cysteine and cysteine/serine proteases inhibitors but was unaffected by specific serine, aspartic and metallo proteases inhibitors. [less ▲]

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See detailMisincorporation of the proline homologue Aze (azetidine-2-carboxylic acid) into recombinant myelin basic protein.
Bessonov, Kyrylo ULg; Bamm, Vladimir V.; Harauz, George

in Phytochemistry (2010), 71(5-6), 502-7

We have evaluated the effects of the proline homologue Aze (1) (azetidine-2-carboxylic acid) on growth of Escherichia coli strains used to over-express recombinant forms of murine myelin basic protein ... [more ▼]

We have evaluated the effects of the proline homologue Aze (1) (azetidine-2-carboxylic acid) on growth of Escherichia coli strains used to over-express recombinant forms of murine myelin basic protein (rmMBP), and on the degree of misincorporation. Addition of Aze to minimal media resulted in severe diminution of growth rate, but rmMBP could still be produced and purified. Mass spectrometry indicated that a detectable proportion of the rmMBP produced had incorporated Aze instead of proline (Pro), to a maximum of three of eleven possible sites. Molecular modelling of a proline-rich region of rmMBP illustrated that the misincorporation of Aze at any site would cause a severe bend in the polypeptide chain, and that multiple Pro-->Aze substitutions would completely disrupt a poly-proline type II structure that has been conjectured to be functionally significant. [less ▲]

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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 ▲]

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See detailIn Vitro Characterization Of The Homogalacturonan-Binding Domain Of The Wall-Associated Kinase Wak1 Using Site-Directed Mutagenesis
Decreux, Annabelle ULg; Thomas, Annick ULg; Spies, B. et al

in Phytochemistry (2006), 67(11), 1068-79

Wall-associated kinase 1--WAK1 is a transmembrane protein containing a cytoplasmic Ser/Thr kinase domain and an extracellular domain in contact with the pectin fraction of the plant cell wall in ... [more ▼]

Wall-associated kinase 1--WAK1 is a transmembrane protein containing a cytoplasmic Ser/Thr kinase domain and an extracellular domain in contact with the pectin fraction of the plant cell wall in Arabidopsis thaliana (L.) HEYNH. In a previous paper [Decreux, A., Messiaen, J., 2005. Wall-associated kinase WAK1 interacts with cell wall pectins in a calcium-induced conformation. Plant Cell Physiol. 46, 268-278], we showed that a recombinant peptide expressed in yeast corresponding to amino acids 67-254 of the extracellular domain of WAK1 specifically interacts with commercial non-methylesterified homogalacturonic acid, purified homogalacturonans from Arabidopsis and oligogalacturonides in a calcium-induced conformation. In this report, we used a receptor binding domain sequence-based prediction method to identify four putative binding sites in the extracellular domain of WAK1, in which cationic amino acids were selected for substitution by site-directed mutagenesis. Interaction studies between mutated forms of WAK1 and homogalacturonans allowed us to identify and confirm at least five specific amino acids involved in the interaction with homogalacturonan dimers and multimers. The presence of this homogalacturonan-binding domain within the extracellular domain of WAK1 is discussed in terms of cell wall architecture and signal transduction. [less ▲]

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See detailMetabolomic analysis of Strychnos nux-vomica, Strychnos icaja and Strychnos ignatii extracts by H-1 nuclear magnetic resonance spectrometry and multivariate analysis techniques
Frederich, Michel ULg; Choi, Young Hae; Angenot, Luc ULg et al

in Phytochemistry (2004), 65(13), 1993-2001

H-1 Nuclear magnetic resonance spectrometry and multivariate analysis techniques were applied for the metabolic profiling of three Strychnos species: Strychnos nux-vomica (seeds, stem bark, root bark ... [more ▼]

H-1 Nuclear magnetic resonance spectrometry and multivariate analysis techniques were applied for the metabolic profiling of three Strychnos species: Strychnos nux-vomica (seeds, stem bark, root bark), Strychnos ignatii (seeds), and Strychnos icaja (leaves, stem bark, root bark, collar bark). The principal component analysis (PCA) of the H-1 NMR spectra showed a clear discrimination between all samples, using the three first components. The key compounds responsible for the discrimination were brucine, loganin, fatty acids.. and Strychnos icaja alkaloids such as icajine and sungucine. The method was then applied to the classification of several "false angostura" samples. These samples were, as expected, identified as S. nux-vomica by PCA, but could not be clearly discriminated as root bark or stem bark samples after further statistical analysis. (C) 2004 Published by Elsevier Ltd. [less ▲]

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See detailLC/MS/NMR analysis of isomeric divanilloylquinic acids from the root bark of Fagara zanthoxyloides Lam
Ouattara, Badiore; Angenot, Luc ULg; Guissou, Pierre et al

in Phytochemistry (2004), 65(8), 1145-1151

Gradient HPLC coupled to DAD/UV, MS/MS and NMR has been applied to the rapid structure determination of three new isomeric divanilloylquinic acids from Fagara zanthoxyloides collected in Burkina Faso: 3,4 ... [more ▼]

Gradient HPLC coupled to DAD/UV, MS/MS and NMR has been applied to the rapid structure determination of three new isomeric divanilloylquinic acids from Fagara zanthoxyloides collected in Burkina Faso: 3,4-O-divanilloylquinic acid, 3,5-O-divanilloylquinic acid and 4,5-O-divanilloylquinic acid. Furthermore these new compounds named burkinabins A-C could play a useful role in sickle cell disease, as the active agents of Fagara zanthoxyloides are said to be unidentified aromatic compounds with carboxylic acid grouping (Adesanya, S.A., Sofowora, A., 1983. Biological standardisation of Zanthoxylum roots for antisickling activity. Planta Med. 48, 27-33). (C) 2004 Elsevier Ltd. All rights reserved. [less ▲]

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See detailDiterpenes from the leaves of Croton Zambesicus
Block, Sébastien; Baccelli, Chiara; Tinant, Bernard et al

in Phytochemistry (2004), 65

Two new trachylobane- and one isopimarane-type diterpenoids: ent-18-hydroxy-trachyloban-3-one; ent-trachyloban-3-one; isopimara-7,15-dien-3b-ol, were isolated from the leaves of Croton zambesicus ... [more ▼]

Two new trachylobane- and one isopimarane-type diterpenoids: ent-18-hydroxy-trachyloban-3-one; ent-trachyloban-3-one; isopimara-7,15-dien-3b-ol, were isolated from the leaves of Croton zambesicus, together with trans-phytol, b-sitosterol, a-amyrin and stigmasterol. The structures were determined by extensive NMR techniques and X-ray analysis. The cytotoxicity of these compounds has been evaluated on cancer and non-cancer cell-lines. [less ▲]

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See detailIndolomonoterpenic alkaloids from Strychnos icaja roots
Philippe, Geneviève ULg; De Mol, Patrick ULg; Zeches-Hanrot, M. et al

in Phytochemistry (2003), 62(4), 623-629

In the course of our search for new antiplasmodial alkaloids from Strychnos icaja, we have isolated five alkaloids: three monomers, protostrychnine and genostrychnine, previously described in Strychnos ... [more ▼]

In the course of our search for new antiplasmodial alkaloids from Strychnos icaja, we have isolated five alkaloids: three monomers, protostrychnine and genostrychnine, previously described in Strychnos nux-vomica, pseudostrychnine, already found in the leaves of the plant, a new bisindolic alkaloid, named strychnogucine C, and the first naturally occurring trimeric indolomonoterpenic alkaloid: strychnohexamine. This latter trimeric alkaloid presented an antiplasmodial activity against the FCA Plasmodium falciparum line near I muM. (C) 2002 Elsevier Science Ltd. All rights reserved. [less ▲]

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See detail5',6'-Dehydroguiachrysine and 5',6'-Dehydroguiaflavine, Two Curarizing Quaternary Indole Alkaloids from the Stem Bark of Strychnos Guianensis
Penelle, J.; Christen, P.; Molgo, J. et al

in Phytochemistry (2001), 58(4), 619-26

Two new quaternary indole alkaloids 5',6'-dehydroguiachrysine (1) and 5',6'-dehydroguiaflavine (2) were isolated from Strychnos guianensis stem bark. Their structures were determined by analysis of ... [more ▼]

Two new quaternary indole alkaloids 5',6'-dehydroguiachrysine (1) and 5',6'-dehydroguiaflavine (2) were isolated from Strychnos guianensis stem bark. Their structures were determined by analysis of spectral data. Their inhibitory effects on neuromuscular transmission are also reported and compared to that of other quaternary alkaloids. [less ▲]

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See detailMain Glucosidase Conversion Products of the Gluco-Alkaloids Dolichantoside and Palicoside
Brandt, V.; Tits, Monique ULg; Penelle, J. et al

in Phytochemistry (2001), 57(5), 653-9

The enzymatic glucose cleavage of palicoside revealed the biosynthetic pathway to akagerine, whereas the conversion of dolichantoside led to a new quaternary heteroyohimbine alkaloid named N(b)-methyl-21 ... [more ▼]

The enzymatic glucose cleavage of palicoside revealed the biosynthetic pathway to akagerine, whereas the conversion of dolichantoside led to a new quaternary heteroyohimbine alkaloid named N(b)-methyl-21-beta-hydroxy-mayumbine. The hypothetical models of reactions occurring after the conversion of both substrates are proposed. Dolichantoside and palicoside, as well as Strychnos mellodora stem bark crude ethanol extract, exhibit significant antimycotic activity against human pathogens in presence of specific glucosidase. [less ▲]

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See detailQuaternary Indole Alkaloids from the Stem Bark of Strychnos Guianensis
Penelle, Jacques; Tits, Monique ULg; Christen, Philippe et al

in Phytochemistry (2000), 53(8), 1057-66

Two new quaternary alkaloids, 9-methoxy-Nb-methylgeissoschizol and guiachrysine together with the known compounds C-alkaloid O, fluorocurine, mavacurine, macusine B and C-profluorocurine, were isolated ... [more ▼]

Two new quaternary alkaloids, 9-methoxy-Nb-methylgeissoschizol and guiachrysine together with the known compounds C-alkaloid O, fluorocurine, mavacurine, macusine B and C-profluorocurine, were isolated from Strychnos guianensis stembark. The structures of the compounds were elucidated on the basis of spectroscopic studies. [less ▲]

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See detailbeta-carboline glucoalkaloids from Strychnos mellodora
Brandt, V.; Tits, Monique ULg; Geerlings, A. et al

in Phytochemistry (1999), 51(8), 1171-1176

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See detail3 ',4 ',5 ',6 ' tetradehydrolongicaudatine Y, an anhydronium base from Strychnos usambarensis
Frederich, Michel ULg; Quetin-Leclercq, J.; Biala, R. G. et al

in Phytochemistry (1998), 48(7), 1263-1266

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See detail9-Methoxygeissoschizol, an alkaloid from bark of strychnos guianensis
Mavar-Manga, Hélène; Quetin-Leclercq, Joëlle; Llabres, Gabriel ULg et al

in Phytochemistry (1996), 43(5), 1125-1127

The isolation and structure determination of 9-methoxygeissoschizol from the stem bark of Strychnos guianensis is described. Elucidation of its structure is mainly based on NMR studies.

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See detailGuianensine, a zwitterionic alkaloid from Strychnos guianensis
Quetin-Leclercq, Joëlle; Llabres, Gabriel ULg; Warin, Roger et al

in Phytochemistry (1995), 40(5), 1557-1560

The isolation and structure determination of an alkaloid isolated from the stem bark of Strychnos guianensis is described. Elucidation of its structure is based mainly on 1D and 2D NMR studies. The new ... [more ▼]

The isolation and structure determination of an alkaloid isolated from the stem bark of Strychnos guianensis is described. Elucidation of its structure is based mainly on 1D and 2D NMR studies. The new alkaloid has a zwitterionic asymmetrical bis-indole structure and is named guianensine. [less ▲]

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See detail2,7-dihydroapogeissoschizine from root bark of strychnos Gossweileri
Quetin-Leclercq, Joëlle; Dive, Georges ULg; Delaude, Clément et al

in Phytochemistry (1994), 35(2), 533-536

In this paper, we describe the isolation and structural determination of 2,7-dihydroxyapogeissoschizine, a new alkaloid from the root bark of Strychnos gossweileri. Elucidation of its structure is based ... [more ▼]

In this paper, we describe the isolation and structural determination of 2,7-dihydroxyapogeissoschizine, a new alkaloid from the root bark of Strychnos gossweileri. Elucidation of its structure is based mainly on 1D and 2D NMR studies; its conformation was optimized by energy minimization. This type of skeleton is related to geissoschizine but with the notable diffrence that the 1 and 17 positions are joined giving an additional fused ring. Such a seven-membered ring has ,to our knowledge, only been observed in apogeissoschizine, obtained after chemical tratment of two alkaloids ( geissospermine and geissoschizine). 2,7-dihydroxyapogeissoschizine is therefore, the first natural product possessing this skeleton. According to a preliminary test, this new alkaloid shows low toxicity to B16 melanoma cells, but not for non-cancer 3T3 fibroblasts cultured in vitro.THese results have to be confirmed by further tests. [less ▲]

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See detailProdelphinidins from Ribes nigrum
Tits, Monique ULg; Angenot, Luc ULg; Poukens, P. et al

in Phytochemistry (1992), 31(3), 971-973

Ribes nigrum leaves yielded three anti-inflammatory prodelphinidins. these compounds were identified and characterized; two known prodelphinidin dimers gallocatechin-(4-8)-epigallocatechin and ... [more ▼]

Ribes nigrum leaves yielded three anti-inflammatory prodelphinidins. these compounds were identified and characterized; two known prodelphinidin dimers gallocatechin-(4-8)-epigallocatechin and gallocatechin-(4-8)-gallocatechin found together for the first time and a new prodelphinidin trimer galocatechin-(4-8)-gallocatechin-(4-8)-gallocatechin. [less ▲]

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See detailRevision of the structure of strychnofluorine, an alkaloid of Strychnos gossweileri
Quetin-Leclercq, Joëlle; Coune, Claude; Delaude, Clément et al

in Phytochemistry (1992), 31(12), 4347-4349

The structure of strychnofluorine, an indole alkaloid isolated in 1980 from the root bark of Strychnos gossweileri, has been revised. Strychnofluorine proved to be identical with 18 ... [more ▼]

The structure of strychnofluorine, an indole alkaloid isolated in 1980 from the root bark of Strychnos gossweileri, has been revised. Strychnofluorine proved to be identical with 18-hydroxynorfluorocurarine that has been isolated as a minor (contaminated) alkaloid from Strychnos ngouniensis in 1983. [less ▲]

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See detailMatadine, a cytotoxic alkaloid from Strychnos gossweileri
Quetin-Leclercq, Joëlle; Coucke, P.; Delaude, Clément et al

in Phytochemistry (1991), 30(5), 1697-1700

Matadine, a new alkaloid, has been isolated from the root bark of Strychnos gossweileri. Elucidation of its structure is mainly based on 1H and 1D NMR studies. Its cytotoxic activity has been tested on ... [more ▼]

Matadine, a new alkaloid, has been isolated from the root bark of Strychnos gossweileri. Elucidation of its structure is mainly based on 1H and 1D NMR studies. Its cytotoxic activity has been tested on cancer cells and normal cells. Matadine is an anhydronium base as serpentine, that exerts also a selective inhibiting activity on B16 melanoma cells while it is less toxic in human 2002 non-cancer cells. This selective activity might be well due , as it seems to be the case for serpentine and alstonine, to a higher affinity of matadine for destabilized single-stranded DNA as mainly present in cancer cells. [less ▲]

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