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Robert Verpoorte - One of the best experts on this subject based on the ideXlab platform.
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limitation of mitragynine biosynthesis in mitragyna speciosa roxb korth through tryptamine availability
Zeitschrift für Naturforschung C, 2013Co-Authors: Tossaton Charoonratana, Juraithip Wungsintaweekul, Pathamaporn Pathompak, Milen I Georgiev, Young Hae Choi, Robert VerpoorteAbstract:Metabolite profiles of Mitragyna speciosa were determined by means of 1H NMR-based and HPLC-based analyses. The results indicated that high contents of secologanin, caffeic acid, gallic acid, epigallocatechin, and mitragynine were accumulated in leaves. In M. speciosa, feedings of tryptamine, tryptophan, phenylalanine or tyrosine significantly increased the mitragynine contents. Feedings of tryptamine and loganin also enhanced the mitragynine accumulation, but feeding of loganin only did not affect the mitragynine level. The mRNA levels of anthranilate synthase alpha subunit (ASA), tryptophan decarboxylase (TDC), and strictosidine synthase (STR) were measured by quantitative real-time polymerase chain reaction (RT-qPCR) in control plants and those exposed to methyl jasmonate (MJ; 10 microM). All genes responded to MJ after a 24-h treatment. The mitragynine contents were also enhanced and corresponded to the transcript levels. From the present results we conclude that a high content of secologanin together with a undetectable level of tryptamine in M. speciosa feature the limitation of mitragynine biosynthesis. Additionally, expression of all the genes limits production of an essential precursor for mitragynine production.
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Alkaloid formation in cell suspension cultures of Tabernaemontana elegans after feeding of tryptamine and loganin or secologanin
Plant Cell Tissue and Organ Culture, 2002Co-Authors: E. Lucumi, R. Van Der Heijden, D. Hallard, A. Vera, Robert VerpoorteAbstract:A cell suspension culture of Tabernaemontana elegans lost its ability to produce alkaloids after a prolonged period of subculture. To determine whether it was still capable of performing the later steps of the alkaloid biosynthetic pathway, the culture was fed with tryptamine and loganin. The precursors and alkaloids were determined in the biomass and in the medium during a growth cycle. In this culture, an increase in the amount of serotonin was found in the biomass after feeding of tryptamine and loganin. Secologanin was detected in small amounts but strictosidine was not. Therefore, a limitation in alkaloid formation in this T. elegans cell line occured in the formation of secologanin from loganin. After feeding of secologanin alone, strictosidine, 10-hydroxy strictosidine, strictosidinic acid and two other indole alkaloids, as yet unidentified, were formed. However, the alkaloids originally produced by this cell line were not found. As the biosynthesis is impaired at several steps, it seems that the loss of productivity is more likely to be to a change on the level of the regulation of the pathway, than due to the loss of the capacity to express an individual biosynthetic gene of the pathway.
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Screening method for cDNAs encoding putative enzymes converting loganin into secologanin by a transgenic yeast culture
Biotechnology Techniques, 1999Co-Authors: Arjan Geerlings, Adriana Contin, Robert Van Der Heijden, Johan Memelink, Francisco Javier Redondo, Robert VerpoorteAbstract:A screening method was developed for the detection of enzymes converting loganin to secologanin, a precursor in the biosynthesis of indole alkaloids. The method uses a transgenic yeast culture expressing two cDNAs encoding enzymes involved in the terpenoid indole alkaloid biosynthesis. In the presence of secologanin, the yeast culture produces a yellow compound visible on nitrocellulose. This color change was used to screen a cDNA library of Catharanthus roseus for a putative enzyme converting loganin into secologanin.
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Accumulation of loganin and secologanin in vacuoles from suspension cultured Catharanthus roseus cells
Plant Science, 1999Co-Authors: Adriana Contin, Robert Van Der Heijden, Robert VerpoorteAbstract:The distribution of the iridoids loganin and secologanin at the subcellular level was studied in secologanin accumulating Catharanthus roseus cells. Vacuoles were isolated from protoplasts by an osmotic shock treatment, followed by flotation centrifugation. The iridoid and alkaloid contents of cells, protoplasts and vacuoles were analysed by HPLC. Secologanin was found to be stored exclusively in the vacuoles. In loganin fed cells, loganin accumulated in the vacuoles while vacuolar secologanin contents increased, indicating that the conversion of loganin to secologanin occurs in the vacuoles. However, feedings of loganin to isolated protoplasts and vacuoles did not result in increased secologanin levels. Utilizing these strategies we attempted to substantiate the possible vacuolar conversion of loganin to secologanin.
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The iridoid glucoside secologanin is derived from the novel triose phosphate/pyruvate pathway in a Catharanthus roseus cell culture
FEBS letters, 1998Co-Authors: Adriana Contin, Robert Van Der Heijden, Alfons W.m. Lefeber, Robert VerpoorteAbstract:Abstract Secologanin is the iridoid building block of the majority of the terpenoid indole alkaloids. In the biosynthesis of secologanin, mevalonate was considered to be the exclusive precursor of isopentenyl diphosphate. After [1-13C]glucose feeding to a cell culture of Catharanthus roseus, its incorporation into secologanin was studied by 13C NMR spectroscopy. The data showed that the novel triose phosphate/pyruvate and not the mevalonate pathway was the major route for the biosynthesis of secologanin.
Richard T. Brown - One of the best experts on this subject based on the ideXlab platform.
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short stereoselective syntheses of ajmalicine 3 iso ajmalicine and their 5 methoxycarbonyl derivatives from secologanin
Heterocycles, 2002Co-Authors: Richard T. Brown, Simon B. Pratt, Bukar E N Dauda, Paul RichardsAbstract:Enzymatic hydrolysis of secologanin ethylene acetal at pH 5.0 resulted in stereoselective rearrangement of its aglucone to a dihydropyran aldehyde, which on reductive amination with tryptamine and cyclisation afforded 3-iso-ajmalicine, subsequently inverted to ajmalicine; analogous use of methyl S-tryptophanate gave 5S-methoxycarbonyl-3-iso-ajmalicine, whereas the R-enantiomer rather surprisingly yielded the ajmalicine derivative, whose anomalous CD spectrum has been rationalised.
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synthesis of 18r hydroxy epiallo yohimbines from 3 iso 19 20 dehydro β yohimbine an enantiospecific route to deserpidine and reserpine analogues from secologanin
Tetrahedron Letters, 2000Co-Authors: Falmai Binns, Richard T. Brown, Bukar E N DaudaAbstract:Abstract (−)-3-Iso-19,20-dehydro-β-yohimbine has been converted into epiallo -yohimbines and, via a novel regio- and stereoselective hydration, into the 18 R -hydroxy derivative, an analogue of deserpidine. Its 11-methoxy derivative, also prepared from secologanin, is a potential precursor for a reserpine analogue.
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enantiospecific synthesis of 3 iso 19 20 dehydro β yohimbine from secologanin a route to normal and pseudo stereoisomers of yohimbine
Tetrahedron Letters, 2000Co-Authors: Richard T. Brown, Simon B. Pratt, Paul RichardsAbstract:Abstract Hydrolysis of secologanin ethylene acetal at pH 7 resulted in stereoselective aldol cyclisation to a cyclohexene aldehyde, which, on reductive amination and cyclisation with tryptamine afforded (−)-3-iso-19,20-dehydro-β-yohimbine, converted into various normal and pseudo isomers of yohimbine.
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Enantiospecific, diastereoselective synthesis of Aspidosperma alkaloid analogues from secologanin
Tetrahedron Letters, 2000Co-Authors: Richard T. Brown, Mythily KandasamyAbstract:Abstract Pure enantiomers of two diastereomeric Aspidosperma alkaloid analogues antipodal at the spiro and adjacent centres have been prepared, as kinetic and thermodynamic products, respectively, in a biomimetic sequence via a secodine-like intermediate from a secologanin derivative and Kuehne's indolo-azepine.
Bukar E N Dauda - One of the best experts on this subject based on the ideXlab platform.
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short stereoselective syntheses of ajmalicine 3 iso ajmalicine and their 5 methoxycarbonyl derivatives from secologanin
Heterocycles, 2002Co-Authors: Richard T. Brown, Simon B. Pratt, Bukar E N Dauda, Paul RichardsAbstract:Enzymatic hydrolysis of secologanin ethylene acetal at pH 5.0 resulted in stereoselective rearrangement of its aglucone to a dihydropyran aldehyde, which on reductive amination with tryptamine and cyclisation afforded 3-iso-ajmalicine, subsequently inverted to ajmalicine; analogous use of methyl S-tryptophanate gave 5S-methoxycarbonyl-3-iso-ajmalicine, whereas the R-enantiomer rather surprisingly yielded the ajmalicine derivative, whose anomalous CD spectrum has been rationalised.
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synthesis of 18r hydroxy epiallo yohimbines from 3 iso 19 20 dehydro β yohimbine an enantiospecific route to deserpidine and reserpine analogues from secologanin
Tetrahedron Letters, 2000Co-Authors: Falmai Binns, Richard T. Brown, Bukar E N DaudaAbstract:Abstract (−)-3-Iso-19,20-dehydro-β-yohimbine has been converted into epiallo -yohimbines and, via a novel regio- and stereoselective hydration, into the 18 R -hydroxy derivative, an analogue of deserpidine. Its 11-methoxy derivative, also prepared from secologanin, is a potential precursor for a reserpine analogue.
Paul Richards - One of the best experts on this subject based on the ideXlab platform.
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short stereoselective syntheses of ajmalicine 3 iso ajmalicine and their 5 methoxycarbonyl derivatives from secologanin
Heterocycles, 2002Co-Authors: Richard T. Brown, Simon B. Pratt, Bukar E N Dauda, Paul RichardsAbstract:Enzymatic hydrolysis of secologanin ethylene acetal at pH 5.0 resulted in stereoselective rearrangement of its aglucone to a dihydropyran aldehyde, which on reductive amination with tryptamine and cyclisation afforded 3-iso-ajmalicine, subsequently inverted to ajmalicine; analogous use of methyl S-tryptophanate gave 5S-methoxycarbonyl-3-iso-ajmalicine, whereas the R-enantiomer rather surprisingly yielded the ajmalicine derivative, whose anomalous CD spectrum has been rationalised.
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enantiospecific synthesis of 3 iso 19 20 dehydro β yohimbine from secologanin a route to normal and pseudo stereoisomers of yohimbine
Tetrahedron Letters, 2000Co-Authors: Richard T. Brown, Simon B. Pratt, Paul RichardsAbstract:Abstract Hydrolysis of secologanin ethylene acetal at pH 7 resulted in stereoselective aldol cyclisation to a cyclohexene aldehyde, which, on reductive amination and cyclisation with tryptamine afforded (−)-3-iso-19,20-dehydro-β-yohimbine, converted into various normal and pseudo isomers of yohimbine.
Adriana Contin - One of the best experts on this subject based on the ideXlab platform.
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Screening method for cDNAs encoding putative enzymes converting loganin into secologanin by a transgenic yeast culture
Biotechnology Techniques, 1999Co-Authors: Arjan Geerlings, Adriana Contin, Robert Van Der Heijden, Johan Memelink, Francisco Javier Redondo, Robert VerpoorteAbstract:A screening method was developed for the detection of enzymes converting loganin to secologanin, a precursor in the biosynthesis of indole alkaloids. The method uses a transgenic yeast culture expressing two cDNAs encoding enzymes involved in the terpenoid indole alkaloid biosynthesis. In the presence of secologanin, the yeast culture produces a yellow compound visible on nitrocellulose. This color change was used to screen a cDNA library of Catharanthus roseus for a putative enzyme converting loganin into secologanin.
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Accumulation of loganin and secologanin in vacuoles from suspension cultured Catharanthus roseus cells
Plant Science, 1999Co-Authors: Adriana Contin, Robert Van Der Heijden, Robert VerpoorteAbstract:The distribution of the iridoids loganin and secologanin at the subcellular level was studied in secologanin accumulating Catharanthus roseus cells. Vacuoles were isolated from protoplasts by an osmotic shock treatment, followed by flotation centrifugation. The iridoid and alkaloid contents of cells, protoplasts and vacuoles were analysed by HPLC. Secologanin was found to be stored exclusively in the vacuoles. In loganin fed cells, loganin accumulated in the vacuoles while vacuolar secologanin contents increased, indicating that the conversion of loganin to secologanin occurs in the vacuoles. However, feedings of loganin to isolated protoplasts and vacuoles did not result in increased secologanin levels. Utilizing these strategies we attempted to substantiate the possible vacuolar conversion of loganin to secologanin.
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The iridoid glucoside secologanin is derived from the novel triose phosphate/pyruvate pathway in a Catharanthus roseus cell culture
FEBS letters, 1998Co-Authors: Adriana Contin, Robert Van Der Heijden, Alfons W.m. Lefeber, Robert VerpoorteAbstract:Abstract Secologanin is the iridoid building block of the majority of the terpenoid indole alkaloids. In the biosynthesis of secologanin, mevalonate was considered to be the exclusive precursor of isopentenyl diphosphate. After [1-13C]glucose feeding to a cell culture of Catharanthus roseus, its incorporation into secologanin was studied by 13C NMR spectroscopy. The data showed that the novel triose phosphate/pyruvate and not the mevalonate pathway was the major route for the biosynthesis of secologanin.
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the iridoid glucoside secologanin is derived from the novel triose phosphate pyruvate pathway in a catharanthus roseus cell culture
FEBS Letters, 1998Co-Authors: Adriana Contin, Robert Van Der Heijden, Alfons W.m. Lefeber, Robert VerpoorteAbstract:Abstract Secologanin is the iridoid building block of the majority of the terpenoid indole alkaloids. In the biosynthesis of secologanin, mevalonate was considered to be the exclusive precursor of isopentenyl diphosphate. After [1-13C]glucose feeding to a cell culture of Catharanthus roseus, its incorporation into secologanin was studied by 13C NMR spectroscopy. The data showed that the novel triose phosphate/pyruvate and not the mevalonate pathway was the major route for the biosynthesis of secologanin.
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An assay for secologanin in plant tissues based on enzymatic conversion into strictosidine
Phytochemical Analysis, 1998Co-Authors: D. Hallard, Soren Rosendal Jensen, Adriana Contin, Robert Van Der Heijden, Robert Verpoorte, Emilia M. Tomas Jiménéz, Wim Snoeijer, M. Inês Lopes Cardoso, Giancarlo Pasquali, Johan MemelinkAbstract:The secoiridoid glucoside secologanin is the terpenoid building block in the biosynthesis of terpenoid indole alkaloids. A method for its determination in plant tissues and in cell suspension cultures has been developed. This assay is based on the condensation of secologanin with tryptamine, yielding strictosidine, in a reaction catalysed by the enzyme strictosidine synthase (STR; E.C. 4.3.3.2). Subsequently, the formation of strictosidine is quantified by high performance liquid chromatography (HPLC). STR was isolated from transgenic Nicotiana tabacum cells expressing a cDNA-derived gene coding for STR from Catharanthus roseus. The high specificity of STR for secologanin, in combination with a sensitive and selective HPLC system, allows a simple extraction of secologanin from plant tissue. The detection limit of this method is 15 ng secologanin. Using this assay, secologanin contents were determined in tissues of various plant species; Lonicera xylosteum hairy roots were found to contain 1% of secologanin on a dry weight basis. # 1998 John Wiley & Sons, Ltd. Phytochem. Anal. 9, 162‐167, 1998
