The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Markus Ganzera - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Determination of Lactones in Piper Methysticum (Kava-Kava) by Supercritical Fluid Chromatography
Planta Medica, 2017Co-Authors: Adele Murauer, Markus GanzeraAbstract:A fast and validated supercritical fluid chromatography method for the quantitative determination of major lactones in Piper Methysticum, a plant used against nervous anxiety, stress, and restlessness, was developed. The baseline separation of dihydrokavain, demethoxyyangonin, kavain, yangonin, dihydromethysticin, and methysticin was possible in less than 4 min on an Aquity UPC2 BEH 1.7 µm column, in combination with a mobile phase comprising CO2 and methanol with diethylamine. The column temperature had a great impact on the results because only at 70 °C could kavain and yangonin be fully resolved. With correlation coefficients above 0.998, recovery rates between 95.9 and 104.1 % as well as limit of detection values below 1.5 ng on-column, the procedure fulfilled all validation requirements and was well suited for the quantitative analysis of commercial products containing P. Methysticum root powder and/or extract. All of them contained the target analytes, however, the absolute content of lactones was quite variable. Accordingly, depending on the product, the total daily intake of lactones varied from 56 to 312 mg. Concerning speed, selectivity, and environmental friendly operation, this supercritical fluid chromatography approach surpasses all previously reported ones.
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Quantitative Determination of Lactones in Piper Methysticum (Kava-Kava) by Supercritical Fluid Chromatography
Planta Medica, 2017Co-Authors: Adele Murauer, Markus GanzeraAbstract:A fast and validated supercritical fluid chromatography method for the quantitative determination of major lactones in Piper Methysticum, a plant used against nervous anxiety, stress, and restlessness, was developed. The baseline separation of dihydrokavain, demethoxyyangonin, kavain, yangonin, dihydromethysticin, and methysticin was possible in less than 4 min on an Aquity UPC2 BEH 1.7 µm column, in combination with a mobile phase comprising CO2 and methanol with diethylamine. The column temperature had a great impact on the results because only at 70 °C could kavain and yangonin be fully resolved. With correlation coefficients above 0.998, recovery rates between 95.9 and 104.1 % as well as limit of detection values below 1.5 ng on-column, the procedure fulfilled all validation requirements and was well suited for the quantitative analysis of commercial products containing P. Methysticum root powder and/or extract. All of them contained the target analytes, however, the absolute content of lactones was quite variable. Accordingly, depending on the product, the total daily intake of lactones varied from 56 to 312 mg. Concerning speed, selectivity, and environmental friendly operation, this supercritical fluid chromatography approach surpasses all previously reported ones.
Adele Murauer - One of the best experts on this subject based on the ideXlab platform.
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Quantitative Determination of Lactones in Piper Methysticum (Kava-Kava) by Supercritical Fluid Chromatography
Planta Medica, 2017Co-Authors: Adele Murauer, Markus GanzeraAbstract:A fast and validated supercritical fluid chromatography method for the quantitative determination of major lactones in Piper Methysticum, a plant used against nervous anxiety, stress, and restlessness, was developed. The baseline separation of dihydrokavain, demethoxyyangonin, kavain, yangonin, dihydromethysticin, and methysticin was possible in less than 4 min on an Aquity UPC2 BEH 1.7 µm column, in combination with a mobile phase comprising CO2 and methanol with diethylamine. The column temperature had a great impact on the results because only at 70 °C could kavain and yangonin be fully resolved. With correlation coefficients above 0.998, recovery rates between 95.9 and 104.1 % as well as limit of detection values below 1.5 ng on-column, the procedure fulfilled all validation requirements and was well suited for the quantitative analysis of commercial products containing P. Methysticum root powder and/or extract. All of them contained the target analytes, however, the absolute content of lactones was quite variable. Accordingly, depending on the product, the total daily intake of lactones varied from 56 to 312 mg. Concerning speed, selectivity, and environmental friendly operation, this supercritical fluid chromatography approach surpasses all previously reported ones.
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Quantitative Determination of Lactones in Piper Methysticum (Kava-Kava) by Supercritical Fluid Chromatography
Planta Medica, 2017Co-Authors: Adele Murauer, Markus GanzeraAbstract:A fast and validated supercritical fluid chromatography method for the quantitative determination of major lactones in Piper Methysticum, a plant used against nervous anxiety, stress, and restlessness, was developed. The baseline separation of dihydrokavain, demethoxyyangonin, kavain, yangonin, dihydromethysticin, and methysticin was possible in less than 4 min on an Aquity UPC2 BEH 1.7 µm column, in combination with a mobile phase comprising CO2 and methanol with diethylamine. The column temperature had a great impact on the results because only at 70 °C could kavain and yangonin be fully resolved. With correlation coefficients above 0.998, recovery rates between 95.9 and 104.1 % as well as limit of detection values below 1.5 ng on-column, the procedure fulfilled all validation requirements and was well suited for the quantitative analysis of commercial products containing P. Methysticum root powder and/or extract. All of them contained the target analytes, however, the absolute content of lactones was quite variable. Accordingly, depending on the product, the total daily intake of lactones varied from 56 to 312 mg. Concerning speed, selectivity, and environmental friendly operation, this supercritical fluid chromatography approach surpasses all previously reported ones.
Chung-shih Tang - One of the best experts on this subject based on the ideXlab platform.
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Structural Characterization of Genuine (-)-Pipermethystine, (-)-EpoxyPipermethystine, (+)-Dihydromethysticin and Yangonin from the Kava Plant (Piper Methysticum):
Natural Product Communications, 2008Co-Authors: Panče Naumov, Klaus Dragull, Masahiro Yoshioka, Chung-shih TangAbstract:Two alkaloids, (-)-Pipermethystine and (-)-epoxyPipermethystine, and two lactones, (+)-dihydromethysticin and yangonin, were isolated from the kava plant (Piper Methysticum) and crystallographicall...
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structural characterization of genuine Pipermethystine epoxyPipermethystine dihydromethysticin and yangonin from the kava plant Piper Methysticum
Natural Product Communications, 2008Co-Authors: Panče Naumov, Klaus Dragull, Masahiro Yoshioka, Chung-shih TangAbstract:Two alkaloids, (-)-Pipermethystine and (-)-epoxyPipermethystine, and two lactones, (+)-dihydromethysticin and yangonin, were isolated from the kava plant (Piper Methysticum) and crystallographicall...
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Kava (Piper Methysticum) Safety Concerns and Studies on Pipermethystine, an Alkaloid in Kava
2008Co-Authors: Jin-woo Jhoo, Klaus Dragull, Catharina Y. W. Ang, Nan Mei, Tao Chen, Chung-shih TangAbstract:Kava (Piper Methysticum) extract products have been associated with a number of severe hepatotoxicity cases. Factors influencing the reported kava-linked liver injuries could include the methods of kava preparation, genetic differences between populations, herbal-drug interactions, enzyme inhibition and minor toxic kava constituents in the kava extracts. This article provides highlights of recent findings on kava safety issues, and also presents results of our current studies on Pipermethystine, a kava alkaloid, in commercial products and its potential mutagenicity. The level of Pipermethystine was found to be negligible in most of the kava dietary supplement products analyzed; however, one product sold as a mixture of kava roots and leaves did contain detectable amounts of Pipermethystine. In vitro mutagenicity tests indicated that Pipermethystine was negative in Salmonella umu assay at a dose range up to 1000 μM and in the mouse lymphoma assay at concentrations lower than 2.5 μg/mL. However, it showed cytotoxicity in mouse lymphoma cells in a dose-response manner.
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In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper Methysticum).
Journal of agricultural and food chemistry, 2006Co-Authors: Jin-woo Jhoo, Klaus Dragull, Chung-shih Tang, James P. Freeman, Thomas M. Heinze, Joanna D. Moody, Laura K. Schnackenberg, Richard D. Beger, Catharina Y. W. AngAbstract:Kava (Piper Methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity. To investigate the key components responsible for the liver toxicity, bioassay-guided fractionation was carried out in this study. Kava roots, leaves, and stem peelings were extracted with methanol, and the resulting residues were subjected to partition with a different polarity of solvents (hexane, ethyl acetate, n-butanol, and water) for evaluation of their cytotoxicity on HepG2 cells based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase and aspartate aminotransferase enzyme leakage assays. Organic solvent fractions displayed a much stronger cytotoxicity than water fractions for all parts of kava. The hex...
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pressurized fluid extraction of carotenoids from haematococcus pluvialis and dunaliella salina and kavalactones from Piper Methysticum
Analytica Chimica Acta, 2003Co-Authors: Judith R Denery, Klaus Dragull, Chung-shih TangAbstract:Abstract Pressurized fluid extraction (PFE) was examined as an alternative technology for the extraction of carotenoids in the green algae Haematococcus pluvialis and Dunaliella salina and kavalactones in Piper Methysticum. The extraction process was optimized by varying the key extraction factors of solvent, sample-solvent ratio, temperature, and time. The selectivity and efficiency of extraction parameters were determined with high performance liquid chromatography (LC) and LC–mass spectrometry (LC–MS). Results showed that PFE utilization of conventional solvents under controlled temperature and pressure in an oxygen and light-free environment could result in the use of less solvent in a shorter period of time. PFE showed higher or equal extraction efficiencies as compared with traditional solvent extractions while maintaining the integrity of chemical components. PFE showed high potential for extraction of natural products and nutraceuticals, particularly labile and light sensitive chemicals.
Vincent Lebot - One of the best experts on this subject based on the ideXlab platform.
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Colorimetric assessment of kava (Piper Methysticum Forst.) quality
Journal of Food Composition and Analysis, 2017Co-Authors: Tiphaine Lhuissier, Pierre-edouard Mercier, Serge Michalet, Vincent Lebot, Laurent LegendreAbstract:Abstract The present study aimed at evaluating the potential of diethyl ether extracts UV/visible (UV/vis) absorbance for assessing the suitability of commercial lots of kava ( Piper Methysticum ). The UV/vis absorption spectra of diethyl ether root extracts of 15 cultivars clustered them into three groups in parallel to their known genetic relatedness and their chemical composition determined by GC–MS and LC–MS analyses. Absorption peaks at 250 nm and 290 nm respectively corresponded to kavain, the most health-promoting kavalactone, and dihydromethysticin a non-desirable kavalactone. The absorbance peak at 340–350 nm reflected the yellow coloration of the extract, which was mainly due to the undesirable flavokavins, desmethoxyyangonin and yangonin. Ratios of absorbance values at 250 nm and 290 nm significantly differentiated all three groups of cultivars, namely ‘noble’ which provide health benefits from ‘two-day’ and ‘wichmannii’ that are health damaging. These results provide a robust and rapid colorimetric test for routine control of a critical aspect of the quality of kava batches.
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Colorimetric assessment of kava (Piper Methysticum Forst.) quality
Journal of Food Composition and Analysis, 2017Co-Authors: Tiphaine Lhuissier, Pierre-edouard Mercier, Serge Michalet, Vincent Lebot, Laurent LegendreAbstract:The present study aimed at evaluating the potential of diethyl ether extracts UV/visible (UV/vis) absorbance for assessing the suitability of commercial lots of kava (Piper Methysticum). The UV/vis absorption spectra of diethyl ether root extracts of 15 cultivars clustered them into three groups in parallel to their known genetic relatedness and their chemical composition determined by GC–MS and LC–MS analyses. Absorption peaks at 250 nm and 290 nm respectively corresponded to kavain, the most health-promoting kavalactone, and dihydromethysticin a non-desirable kavalactone. The absorbance peak at 340–350 nm reflected the yellow coloration of the extract, which was mainly due to the undesirable flavokavins, desmethoxyyangonin and yangonin. Ratios of absorbance values at 250 nm and 290 nm significantly differentiated all three groups of cultivars, namely 'noble' which provide health benefits from 'two-day' and 'wichmannii' that are health damaging. These results provide a robust and rapid colorimetric test for routine control of a critical aspect of the quality of kava batches. (Resume d'auteur)
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Detection of flavokavins (A, B, C) in cultivars of kava (Piper Methysticum) using high performance thin layer chromatography (HPTLC)
Food Chemistry, 2014Co-Authors: Vincent Lebot, L. LegendreAbstract:Kava (Piper Methysticum) is used to prepare the traditional beverage of the Pacific islands. In Europe, kava has been suspected to cause hepatoxicity with flavokavin B (FKB) considered as a possible factor. The present study describes an HPTLC protocol for rapid screening of samples. The objectives are: to detect the presence of flavokavins in extracts and to compare the FKB levels in different cultivars. Overall, 172 samples originating from four cultivars groups (noble, medicinal, two-days and wichmannii), were analysed. Results indicate that the ratio FKB/kavalactones is much higher in two-days (0.39) and wichmannii (0.32) compared to nobles (0.09) and medicinal cultivars (0.10). For each group, the ratios flavokavins/kavalactones do not change significantly between roots, stumps or basal stems and among clones, indicating that they are genetically controlled. This protocol has good accuracy and is cost efficient for routine analysis. We discuss how it could be used for quality control.
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Validation of Piper Methysticum var. wichmannii (Piperaceae)
Novon, 2006Co-Authors: Wendy L. Applequist, Vincent LebotAbstract:ABSTRACT Morphological, chemical, cytological, and genetic data have indicated that kava (Piper Methysticum G. Forster, Piperaceae), a vegetatively propagated plant found only in cultivation, was derived from the wild P. wichmannii C. DC. through artificial selection, and that the two taxa remain similar enough to be considered conspecific. A previous attempt to recognize P. wichmannii (which may also be conspecific with P. subbullatum K. Schumann & Lauterbach) as a variety of P. Methysticum was not validly published owing to failure to cite the place of publication of the basionym. The combination Piper Methysticum var. wichmannii (C. DC.) Lebot is herein validated.
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Identification of factors determining kavalactone content and chemotype in Kava (Piper Methysticum Forst. f.)
Biochemical Systematics and Ecology, 2002Co-Authors: Patricia Siméoni, Vincent LebotAbstract:This study presents results of field experiments conducted to identify factors determining kavalactone content and chemotype in Piper Methysticum. The following factors have been studied: (1) the geographical direction of the roots on the plant, (2) the geographical location of the plant, (3) its age, and (4) its organ (roots, stumps, or basal stems). Overall, 185 samples were analysed by HPLC. It appears that the geographical direction of the roots (North, East, South, West) is not significant. Chemotype and kavalactone content variation among clones of a cultivar grown in a common garden is negligible. There is significant variation among different cultivars originating from the same island. The variation within island is comparable to the variation existing within the whole Vanuatu archipelago. For a given cultivar, chemotype is stable across locations. There are however, chemotype differences between organs. Kavalactone content is always higher in the roots than in the stumps and higher in the stumps than in the basal stems. Experimental data obtained from one cultivar indicate that at the juvenile stage (less than 18 months of growth), kavalactone content is still low but increasing progressively: from 3% of dry matter at 10 months to 8% at 17 months. After two years of vegetative growth, the chemotype appears stable and kavalactone content does not increase but rather fluctuates (±2%). Although seasonal factors might have an effect, it is not possible to observe a significant trend. It is confirmed that chemotype is genetically controlled. However, kavalactone content appears to be greatly determined by the growing conditions, either by the local environment or by the agricultural techniques used by the local farmers. Consequently, the selection of the cultivar, its organ and the geographical area of origin are factors contributing directly to quality control in Piper Methysticum.
Klaus Dragull - One of the best experts on this subject based on the ideXlab platform.
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Structural Characterization of Genuine (-)-Pipermethystine, (-)-EpoxyPipermethystine, (+)-Dihydromethysticin and Yangonin from the Kava Plant (Piper Methysticum):
Natural Product Communications, 2008Co-Authors: Panče Naumov, Klaus Dragull, Masahiro Yoshioka, Chung-shih TangAbstract:Two alkaloids, (-)-Pipermethystine and (-)-epoxyPipermethystine, and two lactones, (+)-dihydromethysticin and yangonin, were isolated from the kava plant (Piper Methysticum) and crystallographicall...
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structural characterization of genuine Pipermethystine epoxyPipermethystine dihydromethysticin and yangonin from the kava plant Piper Methysticum
Natural Product Communications, 2008Co-Authors: Panče Naumov, Klaus Dragull, Masahiro Yoshioka, Chung-shih TangAbstract:Two alkaloids, (-)-Pipermethystine and (-)-epoxyPipermethystine, and two lactones, (+)-dihydromethysticin and yangonin, were isolated from the kava plant (Piper Methysticum) and crystallographicall...
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Kava (Piper Methysticum) Safety Concerns and Studies on Pipermethystine, an Alkaloid in Kava
2008Co-Authors: Jin-woo Jhoo, Klaus Dragull, Catharina Y. W. Ang, Nan Mei, Tao Chen, Chung-shih TangAbstract:Kava (Piper Methysticum) extract products have been associated with a number of severe hepatotoxicity cases. Factors influencing the reported kava-linked liver injuries could include the methods of kava preparation, genetic differences between populations, herbal-drug interactions, enzyme inhibition and minor toxic kava constituents in the kava extracts. This article provides highlights of recent findings on kava safety issues, and also presents results of our current studies on Pipermethystine, a kava alkaloid, in commercial products and its potential mutagenicity. The level of Pipermethystine was found to be negligible in most of the kava dietary supplement products analyzed; however, one product sold as a mixture of kava roots and leaves did contain detectable amounts of Pipermethystine. In vitro mutagenicity tests indicated that Pipermethystine was negative in Salmonella umu assay at a dose range up to 1000 μM and in the mouse lymphoma assay at concentrations lower than 2.5 μg/mL. However, it showed cytotoxicity in mouse lymphoma cells in a dose-response manner.
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In vitro cytotoxicity of nonpolar constituents from different parts of kava plant (Piper Methysticum).
Journal of agricultural and food chemistry, 2006Co-Authors: Jin-woo Jhoo, Klaus Dragull, Chung-shih Tang, James P. Freeman, Thomas M. Heinze, Joanna D. Moody, Laura K. Schnackenberg, Richard D. Beger, Catharina Y. W. AngAbstract:Kava (Piper Methysticum), a perennial shrub native to the South Pacific islands, has been used to relieve anxiety. Recently, several cases of severe hepatotoxicity have been reported from the consumption of dietary supplements containing kava. It is unclear whether the kava constituents, kavalactones, are responsible for the associated hepatotoxicity. To investigate the key components responsible for the liver toxicity, bioassay-guided fractionation was carried out in this study. Kava roots, leaves, and stem peelings were extracted with methanol, and the resulting residues were subjected to partition with a different polarity of solvents (hexane, ethyl acetate, n-butanol, and water) for evaluation of their cytotoxicity on HepG2 cells based on the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and lactate dehydrogenase and aspartate aminotransferase enzyme leakage assays. Organic solvent fractions displayed a much stronger cytotoxicity than water fractions for all parts of kava. The hex...
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pressurized fluid extraction of carotenoids from haematococcus pluvialis and dunaliella salina and kavalactones from Piper Methysticum
Analytica Chimica Acta, 2003Co-Authors: Judith R Denery, Klaus Dragull, Chung-shih TangAbstract:Abstract Pressurized fluid extraction (PFE) was examined as an alternative technology for the extraction of carotenoids in the green algae Haematococcus pluvialis and Dunaliella salina and kavalactones in Piper Methysticum. The extraction process was optimized by varying the key extraction factors of solvent, sample-solvent ratio, temperature, and time. The selectivity and efficiency of extraction parameters were determined with high performance liquid chromatography (LC) and LC–mass spectrometry (LC–MS). Results showed that PFE utilization of conventional solvents under controlled temperature and pressure in an oxygen and light-free environment could result in the use of less solvent in a shorter period of time. PFE showed higher or equal extraction efficiencies as compared with traditional solvent extractions while maintaining the integrity of chemical components. PFE showed high potential for extraction of natural products and nutraceuticals, particularly labile and light sensitive chemicals.