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Félix Tomi - One of the best experts on this subject based on the ideXlab platform.
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composition and chemical variability of enantia polycarpa engl diels leaf essential oil from cote d ivoire
Chemistry & Biodiversity, 2018Co-Authors: Zana Adama Ouattara, Jean Brice Boti, Thierry Acafou Yapi, Mathieu Paoli, Ange Bighelli, Joseph Casanova, Zanahi Felix Tonzibo, Félix TomiAbstract:The composition of Enantia polycarpa Engl. & Diels leaf essential oil has been investigated for the first time using a combination of chromatographic and spectroscopic techniques. The compositions of 52 leaf essential oil samples have been subjected to statistical analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Four groups were differentiated, of which the compositions were dominated by β-elemene and germacrene B (Group III, 22/52 samples); germacrene D (Group I, 16/52 samples); β-cubebene (Group IV, 8/52 samples) and by germacrene B and germacrene D (Group II, 6/52 samples). A special attention was brought to the quantification of the thermolabile components, germacrene A, germacrene B and germacrene C, as well as that of their rearranged compounds, β-elemene, γ-elemene and δ-elemene. 13 C-NMR data of β-cubebene have been provided.
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chemical composition of ivorian artabotrys insignis leaf oil combined analysis including 13 c nmr to quantify germacrene a and β elemene
Natural Product Research, 2017Co-Authors: Stephane G Goore, Zana Adama Ouattara, Thierry Acafou Yapi, Pierre Tomi, Mathieu Paoli, Yvesalain Bekro, Félix TomiAbstract:The chemical composition of leaf essential oil from Artabotrys insignis Engler & Diels collected from Cote d'Ivoire was determined by GC(FID), GC-MS and 13C NMR. The main compounds were β-elemene (66.8%) and germacrene A (17.1%). The true content of germacrene A/β-elemene was obtained by combining GC(FID) and 13C NMR data.
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chemical composition of ivorian artabotrys insignis leaf oil combined analysis including 13c nmr to quantify germacrene a and β elemene
Natural Product Research, 2017Co-Authors: Stephane G Goore, Zana Adama Ouattara, Thierry Acafou Yapi, Pierre Tomi, Mathieu Paoli, Yvesalain Bekro, Félix TomiAbstract:AbstractThe chemical composition of leaf essential oil from Artabotrys insignis Engler & Diels collected from Cote d’Ivoire was determined by GC(FID), GC-MS and 13C NMR. The main compounds were β-elemene (66.8%) and germacrene A (17.1%). The true content of germacrene A/β-elemene was obtained by combining GC(FID) and 13C NMR data.
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Analysis of Cleistopholis patens leaf and trunk bark oils using combined GC- flame ionisation detection, GC-retention index, GC-MS and (13) C-NMR.
Phytochemical Analysis, 2013Co-Authors: Zana Adama Ouattara, Jean Brice Boti, Antoine Coffy Ahibo, Félix Tomi, Joseph Casanova, Ange BighelliAbstract:Introduction Germacrenes A–C are secondary metabolites produced by various plants. They are sesquiterpene hydrocarbons bearing the (E,E)-1,5-cyclodecadiene structure known to undergo thermal rearrangement through a [3.3]-sigmatropic reaction. Such a rearrangement was evidenced by comparing the contents of a given germacrene and the corresponding elemene calculated by GC-flame ionisation detection (FID) with the relative intensities of the signals of both molecules in the 13C-NMR spectrum of the mixture, recorded at room temperature. Objective To develop a protocol to identify and quantify germacrenes A, B and C and in parallel the corresponding elemenes, using a combination of GC-FID and 13C-NMR and then provide a correct analysis of Cleistopholis patens essential oils. Methods The essential oil was submitted to GC-FID, GC-retention index, GC–MS and 13C-NMR analyses. The relative percentages of every couple of germacrene and elemene measured by GC-FID were summed. Then, the relative ratio of the mean intensities of the signals of the protonated carbons of a given germacrene and the corresponding elemene was calculated. The contents of both compounds were obtained by combining GC-FID and 13C-NMR data. Results The true content of germacrene A/β-elemene, germacrene B/γ-elemene and germacrene C/δ-elemene in leaf and root oils from C. patens was evaluated by combination of GC-FID and 13C-NMR data. Correct analysis of the essential oils was provided. Conclusion Combined analysis of essential oil including 13C-NMR without isolation of the components, appeared really efficient to identify and quantify germacrene isomers and in parallel elemene isomers in essential oils. Copyright © 2013 John Wiley & Sons, Ltd.
Jennifer Tickner - One of the best experts on this subject based on the ideXlab platform.
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natural Germacrane sesquiterpenes inhibit osteoclast formation bone resorption rankl induced nf κb activation and iκbα degradation
International Journal of Molecular Sciences, 2015Co-Authors: Shengnan Qin, Libing Dai, Xiaohong Yang, Honghui Chen, Lin Zhou, Mingli Yang, Dian Teguh, Renxiang Tan, Estabelle S M Ang, Jennifer TicknerAbstract:Osteolytic bone diseases are commonly presented with enhanced osteoclast formation and bone resorption. Sesquiterpene lactone natural compounds have been found to possess anti-inflammatory and immune-modulation effects. Here, we identified three Germacrane sesquiterpenes using computer-based virtual screening for the structural similarity with sesquiterpene lactone, parthenolide. We showed that natural Germacrane sesquiterpene compounds A, B, and C inhibit osteoclast formation and bone resorption in a dose-dependent manner, with relative potency compound A > compound C > compound B based on their equimolar concentrations. Mechanistic studies by Luciferase reporter gene assay and Western blot analysis showed that Germacrane sesquiterpene compound A inhibits RANKL-induced activation of NF-κB and IκBα degradation. This study reveals that natural Germacrane sesquiterpene compounds are inhibitors for osteoclast formation and bone resorption, and provides evidence that naturally-occurring compounds might be beneficial as alternative medicine for the prevention and treatment of osteolysis.
Zana Adama Ouattara - One of the best experts on this subject based on the ideXlab platform.
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composition and chemical variability of enantia polycarpa engl diels leaf essential oil from cote d ivoire
Chemistry & Biodiversity, 2018Co-Authors: Zana Adama Ouattara, Jean Brice Boti, Thierry Acafou Yapi, Mathieu Paoli, Ange Bighelli, Joseph Casanova, Zanahi Felix Tonzibo, Félix TomiAbstract:The composition of Enantia polycarpa Engl. & Diels leaf essential oil has been investigated for the first time using a combination of chromatographic and spectroscopic techniques. The compositions of 52 leaf essential oil samples have been subjected to statistical analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA). Four groups were differentiated, of which the compositions were dominated by β-elemene and germacrene B (Group III, 22/52 samples); germacrene D (Group I, 16/52 samples); β-cubebene (Group IV, 8/52 samples) and by germacrene B and germacrene D (Group II, 6/52 samples). A special attention was brought to the quantification of the thermolabile components, germacrene A, germacrene B and germacrene C, as well as that of their rearranged compounds, β-elemene, γ-elemene and δ-elemene. 13 C-NMR data of β-cubebene have been provided.
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chemical composition of ivorian artabotrys insignis leaf oil combined analysis including 13 c nmr to quantify germacrene a and β elemene
Natural Product Research, 2017Co-Authors: Stephane G Goore, Zana Adama Ouattara, Thierry Acafou Yapi, Pierre Tomi, Mathieu Paoli, Yvesalain Bekro, Félix TomiAbstract:The chemical composition of leaf essential oil from Artabotrys insignis Engler & Diels collected from Cote d'Ivoire was determined by GC(FID), GC-MS and 13C NMR. The main compounds were β-elemene (66.8%) and germacrene A (17.1%). The true content of germacrene A/β-elemene was obtained by combining GC(FID) and 13C NMR data.
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chemical composition of ivorian artabotrys insignis leaf oil combined analysis including 13c nmr to quantify germacrene a and β elemene
Natural Product Research, 2017Co-Authors: Stephane G Goore, Zana Adama Ouattara, Thierry Acafou Yapi, Pierre Tomi, Mathieu Paoli, Yvesalain Bekro, Félix TomiAbstract:AbstractThe chemical composition of leaf essential oil from Artabotrys insignis Engler & Diels collected from Cote d’Ivoire was determined by GC(FID), GC-MS and 13C NMR. The main compounds were β-elemene (66.8%) and germacrene A (17.1%). The true content of germacrene A/β-elemene was obtained by combining GC(FID) and 13C NMR data.
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Analysis of Cleistopholis patens leaf and trunk bark oils using combined GC- flame ionisation detection, GC-retention index, GC-MS and (13) C-NMR.
Phytochemical Analysis, 2013Co-Authors: Zana Adama Ouattara, Jean Brice Boti, Antoine Coffy Ahibo, Félix Tomi, Joseph Casanova, Ange BighelliAbstract:Introduction Germacrenes A–C are secondary metabolites produced by various plants. They are sesquiterpene hydrocarbons bearing the (E,E)-1,5-cyclodecadiene structure known to undergo thermal rearrangement through a [3.3]-sigmatropic reaction. Such a rearrangement was evidenced by comparing the contents of a given germacrene and the corresponding elemene calculated by GC-flame ionisation detection (FID) with the relative intensities of the signals of both molecules in the 13C-NMR spectrum of the mixture, recorded at room temperature. Objective To develop a protocol to identify and quantify germacrenes A, B and C and in parallel the corresponding elemenes, using a combination of GC-FID and 13C-NMR and then provide a correct analysis of Cleistopholis patens essential oils. Methods The essential oil was submitted to GC-FID, GC-retention index, GC–MS and 13C-NMR analyses. The relative percentages of every couple of germacrene and elemene measured by GC-FID were summed. Then, the relative ratio of the mean intensities of the signals of the protonated carbons of a given germacrene and the corresponding elemene was calculated. The contents of both compounds were obtained by combining GC-FID and 13C-NMR data. Results The true content of germacrene A/β-elemene, germacrene B/γ-elemene and germacrene C/δ-elemene in leaf and root oils from C. patens was evaluated by combination of GC-FID and 13C-NMR data. Correct analysis of the essential oils was provided. Conclusion Combined analysis of essential oil including 13C-NMR without isolation of the components, appeared really efficient to identify and quantify germacrene isomers and in parallel elemene isomers in essential oils. Copyright © 2013 John Wiley & Sons, Ltd.
Shengnan Qin - One of the best experts on this subject based on the ideXlab platform.
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Article Natural Germacrane Sesquiterpenes Inhibit Osteoclast Formation, Bone Resorption, RANKL-Induced NF-κB Activation, and IκBα Degradation
2016Co-Authors: Shengnan Qin, Estabelle Ang, Libing Dai, Xiaohong Yang, Honghui Chen, Lin Zhou, Mingli Yang, Dian Teguh, Renxiang TanAbstract:Abstract: Osteolytic bone diseases are commonly presented with enhanced osteoclast formation and bone resorption. Sesquiterpene lactone natural compounds have been found to possess anti-inflammatory and immune-modulation effects. Here, we identified three Germacrane sesquiterpenes using computer-based virtual screening for the structural similarity with sesquiterpene lactone, parthenolide. We showed that natural Germacrane sesquiterpene compounds A, B, and C inhibit osteoclast formation and bone resorption in a dose-dependent manner, with relative potency compound A> compound C> compound B based on their equimolar concentrations. Mechanistic studies by Luciferase reporter gene assay and Western blot analysi
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natural Germacrane sesquiterpenes inhibit osteoclast formation bone resorption rankl induced nf κb activation and iκbα degradation
International Journal of Molecular Sciences, 2015Co-Authors: Shengnan Qin, Libing Dai, Xiaohong Yang, Honghui Chen, Lin Zhou, Mingli Yang, Dian Teguh, Renxiang Tan, Estabelle S M Ang, Jennifer TicknerAbstract:Osteolytic bone diseases are commonly presented with enhanced osteoclast formation and bone resorption. Sesquiterpene lactone natural compounds have been found to possess anti-inflammatory and immune-modulation effects. Here, we identified three Germacrane sesquiterpenes using computer-based virtual screening for the structural similarity with sesquiterpene lactone, parthenolide. We showed that natural Germacrane sesquiterpene compounds A, B, and C inhibit osteoclast formation and bone resorption in a dose-dependent manner, with relative potency compound A > compound C > compound B based on their equimolar concentrations. Mechanistic studies by Luciferase reporter gene assay and Western blot analysis showed that Germacrane sesquiterpene compound A inhibits RANKL-induced activation of NF-κB and IκBα degradation. This study reveals that natural Germacrane sesquiterpene compounds are inhibitors for osteoclast formation and bone resorption, and provides evidence that naturally-occurring compounds might be beneficial as alternative medicine for the prevention and treatment of osteolysis.
Hj Bouwmeester - One of the best experts on this subject based on the ideXlab platform.
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enantiospecific and germacrene d synthases cloned from goldenrod reveal a functionally active variant of the universal isoprenoid biosynthesis aspartate rich motif
Archives of Biochemistry and Biophysics, 2004Co-Authors: Ian M Prosser, Hj Bouwmeester, Iris G Altug, Andrew L. Phillips, Wilfried A. König, Michael H. BealeAbstract:The naturally occurring, volatile sesquiterpene hydrocarbon germacrene D has strong effects on insect behaviour and genes encoding enzymes that produce this compound are of interest in the study of plant–insect interactions and in a number of biotechnological approaches to pest control. Goldenrod, Solidago canadensis, is unusual in that it produces both enantiomers of germacrene D. Two new sesquiterpene synthase cDNAs, designated Sc11 and Sc19, have been isolated from goldenrod and functional expression in Escherichia coli identified Sc11 as (+)-germacrene D synthase and Sc19 as (−)-germacrene D synthase. Thus, the enantiomers of germacrene D are the products of separate, but closely related (85% amino-acid identity), enzymes. Unlike other sesquiterpene synthases and the related monoterpene synthases and prenyl transferases, which contain the characteristic amino-acid motif DDXX(D, E), Sc11 is unusual in that this motif occurs as 303NDTYD. Mutagenesis of this motif to 303DDTYD gave rise to an enzyme that fully retained (+)-germacrene D synthase activity. The converse mutation in Sc19 (D303N) resulted in a less efficient but functional enzyme. Mutagenesis of position 303 to glutamate in both enzymes resulted in loss of activity. These results indicate that the magnesium ion-binding role of the first aspartate in the DDXXD motif may not be as critical as previously thought. Further amino-acid sequence comparisons and molecular modelling of the enzyme structures revealed that very subtle changes to the active site of this family of enzymes are required to alter the reaction pathway to form, in this case, different enantiomers from the same enzyme-bound carbocationic intermediate.
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isolation and characterization of two germacrene a synthase cdna clones from chicory
Plant Physiology, 2002Co-Authors: Hj Bouwmeester, Iris G Altug, J.w. De Kraker, Jan Kodde, Francel W A Verstappen, Thorvald WallaartAbstract:Chicory ( Cichorium intybus ) sesquiterpene lactones were recently shown to be derived from a common sesquiterpene intermediate, (+)-germacrene A. Germacrene A is of interest because of its key role in sesquiterpene lactone biosynthesis and because it is an enzyme-bound intermediate in the biosynthesis of a number of phytoalexins. Using polymerase chain reaction with degenerate primers, we have isolated two sesquiterpene synthases from chicory that exhibited 72% amino acid identity. Heterologous expression of the genes in Escherichia coli has shown that they both catalyze exclusively the formation of (+)-germacrene A, making this the first report, to our knowledge, on the isolation of (+)-germacrene A synthase (GAS)-encoding genes. Northern analysis demonstrated that both genes were expressed in all chicory tissues tested albeit at varying levels. Protein isolation and partial purification from chicory heads demonstrated the presence of two GAS proteins. On MonoQ, these proteins co-eluted with the two heterologously produced proteins. The K m value, pH optimum, and MonoQ elution volume of one of the proteins produced in E. coli were similar to the values reported for the GAS protein that was recently purified from chicory roots. Finally, the two deduced amino acid sequences were modeled, and the resulting protein models were compared with the crystal structure of tobacco ( Nicotiana tabacum ) 5- epi -aristolochene synthase, which forms germacrene A as an enzyme-bound intermediate en route to 5- epi -aristolochene. The possible involvement of a number of amino acids in sesquiterpene synthase product specificity is discussed.
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biosynthesis of germacrene a carboxylic acid in chicory roots demonstration of a cytochrome p450 germacrene a hydroxylase and nadp dependent sesquiterpenoid dehydrogenase s involved in sesquiterpene lactone biosynthesis
Plant Physiology, 2001Co-Authors: Janwillem De Kraker, Marcella C F Dalm, Maurice C R Franssen, Aede De Groot, Hj BouwmeesterAbstract:Sprouts of chicory (Cichorium intybus), a vegetable grown in the dark, have a slightly bitter taste associated with the presence of guaianolides, eudesmanolides, and germacranolides. The committed step in the biosynthesis of these compounds is catalyzed by a (+)-germacrene A synthase. Formation of the lactone ring is the postulated next step in biosynthesis of the germacrene-derived sesquiterpene lactones. The present study confirms this hypothesis by isolation of enzyme activities from chicory roots that introduce a carboxylic acid function in the germacrene A isopropenyl side chain, which is necessary for lactone ring formation. (+)-Germacrene A is hydroxylated to germacra-1(10),4,11(13)-trien-12-ol by a cytochrome P450 enzyme, and is subsequently oxidized to germacra-1(10),4,11(13)-trien-12-oic acid by NADP+-dependent dehydrogenase(s). Both oxidized germacrenes were detected as their Cope-rearrangement products elema-1,3,11(13)-trien-12-ol and elema-1,3,11(13)-trien-12-oic acid, respectively. The cyclization products of germacra-1(10),4,11(13)-trien-12-ol, i.e. costol, were also observed. The (+)-germacrene A hydroxylase is inhibited by carbon monoxide (blue-light reversible), has an optimum pH at 8.0, and hydroxylates β-elemene with a modest degree of enantioselectivity.
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mechanisms of the biosynthesis of sesquiterpene enantiomers and germacrene d in solidago canadensis
Chirality, 1999Co-Authors: Claus O Schmidt, Hj Bouwmeester, Stephan Franke, Wilfried A. KönigAbstract:Sesquiterpenes like germacrene D are naturally occurring in plants, bacteria, fungi, and marine invertebrates. They are important flavor compounds and may be active as antibiotics, insect repellents, attractants, or pheromones or may be produced in response to attacking herbivores. Sesquiterpene synthases (cyclases) catalyze the biosynthesis of sesquiterpenes from the ubiquitous precursor farnesyl diphosphate 1 (FDP, Scheme 1). Most sesquiterpenes are chiral molecules, but usually only one of the two possible enantiomers of a sesquiterpene is produced in a single species. Solidago canadensis is an exception to this rule, because it contains the sesquiterpene enantiomers (+)-germacrene D 2a and (−)-germacrene D 2b in approximately equal amounts. We have isolated two different sesquiterpene synthases from S. canadensis: (+)-germacrene D synthase and (−)-germacrene D synthase. Both synthases catalyze the formation of enantiomerically pure products. After characterizing these synthases biochemically, we studied the mechanisms of the formation of the germacrene D enantiomers. To that end, we incubated both synthases with their substrate trans,trans-farnesyl diphosphate 1 carrying deuterium labels in different positions. Incubation products were analyzed using mass spectrometric techniques. The action of (−)-germacrene D synthase involves a 1,3-hydride shift, whereas (+)-germacrene D is formed via a double 1,2-hydride shift. Chirality 11:353–362, 1999. © 1999 Wiley-Liss, Inc.
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germacrene a biosynthesis the committed step in the biosynthesis of bitter sesquiterpene lactones in chicory
Plant Physiology, 1998Co-Authors: Janwillem De Kraker, Wilfried A. König, Maurice C R Franssen, Aede De Groot, Hj BouwmeesterAbstract:The leaves and especially the roots of chicory (Cichorium intybus L.) contain high concentrations of bitter sesquiterpene lactones such as the guianolides lactupicrin, lactucin, and 8-deoxylactucin. Eudesmanolides and germacranolides are present in smaller amounts. Their postulated biosynthesis through the mevalonate-farnesyl diphosphate-germacradiene pathway has now been confirmed by the isolation of a (+)-germacrene A synthase from chicory roots. This sesquiterpene cyclase was purified 200-fold using a combination of anion-exchange and dye-ligand chromatography. It has a Km value of 6.6 μm, an estimated molecular mass of 54 kD, and a (broad) pH optimum around 6.7. Germacrene A, the enzymatic product, proved to be much more stable than reported in literature. Its heat-induced Cope rearrangement into (−)-β-elemene was utilized to determine its absolute configuration on an enantioselective gas chromatography column. To our knowledge, until now in sesquiterpene biosynthesis, germacrene A has only been reported as an (postulated) enzyme-bound intermediate, which, instead of being released, is subjected to additional cyclization(s) by the same enzyme that generated it from farnesyl diphosphate. However, in chicory germacrene A is released from the sesquiterpene cyclase. Apparently, subsequent oxidations and/or glucosylation of the Germacrane skeleton, together with a germacrene cyclase, determine whether guaiane- or eudesmane-type sesquiterpene lactones are produced.