The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Sven Bode Andersen - One of the best experts on this subject based on the ideXlab platform.
-
molecular activities biosynthesis and evolution of triterpenoid Saponins
Phytochemistry, 2011Co-Authors: Jorg M Augustin, Vera Kuzina, Sven Bode AndersenAbstract:Saponins are bioactive compounds generally considered to be produced by plants to counteract pathogens and herbivores. Besides their role in plant defense, Saponins are of growing interest for drug research as they are active constituents of several folk medicines and provide valuable pharmacological properties. Accordingly, much effort has been put into unraveling the modes of action of Saponins, as well as in exploration of their potential for industrial processes and pharmacology. However, the exploitation of Saponins for bioengineering crop plants with improved resistances against pests as well as circumvention of laborious and uneconomical extraction procedures for industrial production from plants is hampered by the lack of knowledge and availability of genes in saponin biosynthesis. Although the ability to produce Saponins is rather widespread among plants, a complete synthetic pathway has not been elucidated in any single species. Current conceptions consider Saponins to be derived from intermediates of the phytosterol pathway, and predominantly enzymes belonging to the multigene families of oxidosqualene cyclases (OSCs), cytochromes P450 (P450s) and family 1 UDP-glycosyltransferases (UGTs) are thought to be involved in their biosynthesis. Formation of unique structural features involves additional biosynthetical enzymes of diverse phylogenetic background. As an example of this, a serine carboxypeptidase-like acyltransferase (SCPL) was recently found to be involved in synthesis of triterpenoid Saponins in oats. However, the total number of identified genes in saponin biosynthesis remains low as the complexity and diversity of these multigene families impede gene discovery based on sequence analysis and phylogeny. This review summarizes current knowledge of triterpenoid saponin biosynthesis in plants, molecular activities, evolutionary aspects and perspectives for further gene discovery.
Pascal Gerbaux - One of the best experts on this subject based on the ideXlab platform.
-
Tackling saponin diversity in marine animals by mass spectrometry: data acquisition and integration
Analytical and Bioanalytical Chemistry, 2017Co-Authors: Corentin Decroo, Marie Demeyer, Guillaume Caulier, Igor Eeckhaut, Patrick Flammang, Emmanuel Colson, Vincent Lemaur, Jérôme Cornil, Pascal GerbauxAbstract:Saponin analysis by mass spectrometry methods is nowadays progressively supplementing other analytical methods such as nuclear magnetic resonance (NMR). Indeed, saponin extracts from plant or marine animals are often constituted by a complex mixture of (slightly) different saponin molecules that requires extensive purification and separation steps to meet the requirement for NMR spectroscopy measurements. Based on its intrinsic features, mass spectrometry represents an inescapable tool to access the structures of Saponins within extracts by using LC-MS, MALDI-MS, and tandem mass spectrometry experiments. The combination of different MS methods nowadays allows for a nice description of saponin structures, without extensive purification. However, the structural characterization process is based on low kinetic energy CID which cannot afford a total structure elucidation as far as stereochemistry is concerned. Moreover, the structural difference between Saponins in a same extract is often so small that coelution upon LC-MS analysis is unavoidable, rendering the isomeric distinction and characterization by CID challenging or impossible. In the present paper, we introduce ion mobility in combination with liquid chromatography to better tackle the structural complexity of saponin congeners. When analyzing saponin extracts with MS-based methods, handling the data remains problematic for the comprehensive report of the results, but also for their efficient comparison. We here introduce an original schematic representation using sector diagrams that are constructed from mass spectrometry data. We strongly believe that the proposed data integration could be useful for data interpretation since it allows for a direct and fast comparison, both in terms of composition and relative proportion of the saponin contents in different extracts. Graphical Abstract A combination of state-of-the-art mass spectrometry methods, including ion mobility spectroscopy, is developed to afford a complete description of the saponin molecules in natural extracts
-
Mechanisms involved in pearlfish resistance to holothuroid toxins
Marine Biology, 2016Co-Authors: Lola Brasseur, Guillaume Caulier, Patrick Flammang, Pascal Gerbaux, Eric Parmentier, Maryse Vanderplanck, Denis Michez, Georges Lognay, Igor EeckhautAbstract:Holothuroids produce triterpenoid Saponins that act as chemical defenses against predators and parasites. These Saponins interact with sterols of the plasma membranes, inducing the formation of pores and then cell lysis. To avoid such harms from their own Saponins, holothuroids present specific sterols in their tissues. Despite the noxious cytotoxic effect of their chemical defenses, holothuroids host various associates that display specific adaptations to resist to saponin toxicity. Among them, symbiotic carapid fishes (i.e., pearlfishes) are resistant to ichthyotoxic Saponins as they display no stress response and a survival time 45 times longer than free-living fishes without any specific gill adaptation. The present study aims at discovering the resistance mechanism(s) developed by carapids by addressing 3 hypotheses: carapids have (1) a mechanical barrier against the toxin constituted by a larger secretion of mucus than other fishes, (2) a bioactive barrier against the toxins constituted by a mucus effective on Saponins and (3) a Δ^7sterol tissue composition mimicking holothuroids that enable them to resist to Saponins. First experiments showed that the mucus has no effective impact on saponin chemical structures. Mass spectrometry analyses showed that carapids, similarly to non-symbiotic fishes but contrary to their hosts, present a Δ^5sterol tissue composition. However, two different procedures have shown that carapids produce six to ten times more mucus than control fishes, suggesting that a great quantity of mucus can protect carapids from their host’s Saponins and acts as a mechanical barrier against toxins. Therefore, these results provide a new understanding of the carapids–holothuroids relationship.
-
Molecular diversity and body distribution of Saponins in the sea star Asterias rubens by mass spectrometry
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, 2014Co-Authors: Marie Demeyer, Julien De Winter, Guillaume Caulier, Igor Eeckhaut, Patrick Flammang, Pascal GerbauxAbstract:Saponins are natural molecules that the common sea star Asterias rubens produces in the form of steroid glycosides bearing a sulfate group attached on the aglycone part. In order to highlight the inter-organ and inter-individual variability, the saponin contents of five distinct body components, namely the aboral body wall, the oral body wall, the stomach, the pyloric caeca and the gonads, from different individuals were separately analyzed by mass spectrometry. MALDI-ToF experiments were selected as the primary tool for a rapid screening of the saponin mixtures, whereas LC-MS and LC-MS/MS techniques were used to achieve chromatographic separation of isomers. First of all, our analyses demonstrated that the diversity of Saponins is higher than previously reported. Indeed, nine new congeners were observed in addition to the 17 Saponins already described in this species. On the basis of all the collected MS/MS data, we also identified collision-induced key-fragmentations that could be used to reconstruct the molecular structure of both known and unknown saponin ions. Secondly, the comparison of the saponin contents from the five different body components revealed that each organ is characterized by a specific mixture of Saponins and that between animals there are also qualitative and quantitative variability of the saponin contents which could be linked to the sex or to the collecting season. Therefore, the observed high variability unambiguously confirms that Saponins probably fulfill several biological functions in A. rubens. The current results will pave the way for our future studies that will be devoted to the clarification of the biological roles of Saponins in A. rubens at a molecular level. © 2013 Elsevier Inc.
Igor Eeckhaut - One of the best experts on this subject based on the ideXlab platform.
-
Tackling saponin diversity in marine animals by mass spectrometry: data acquisition and integration
Analytical and Bioanalytical Chemistry, 2017Co-Authors: Corentin Decroo, Marie Demeyer, Guillaume Caulier, Igor Eeckhaut, Patrick Flammang, Emmanuel Colson, Vincent Lemaur, Jérôme Cornil, Pascal GerbauxAbstract:Saponin analysis by mass spectrometry methods is nowadays progressively supplementing other analytical methods such as nuclear magnetic resonance (NMR). Indeed, saponin extracts from plant or marine animals are often constituted by a complex mixture of (slightly) different saponin molecules that requires extensive purification and separation steps to meet the requirement for NMR spectroscopy measurements. Based on its intrinsic features, mass spectrometry represents an inescapable tool to access the structures of Saponins within extracts by using LC-MS, MALDI-MS, and tandem mass spectrometry experiments. The combination of different MS methods nowadays allows for a nice description of saponin structures, without extensive purification. However, the structural characterization process is based on low kinetic energy CID which cannot afford a total structure elucidation as far as stereochemistry is concerned. Moreover, the structural difference between Saponins in a same extract is often so small that coelution upon LC-MS analysis is unavoidable, rendering the isomeric distinction and characterization by CID challenging or impossible. In the present paper, we introduce ion mobility in combination with liquid chromatography to better tackle the structural complexity of saponin congeners. When analyzing saponin extracts with MS-based methods, handling the data remains problematic for the comprehensive report of the results, but also for their efficient comparison. We here introduce an original schematic representation using sector diagrams that are constructed from mass spectrometry data. We strongly believe that the proposed data integration could be useful for data interpretation since it allows for a direct and fast comparison, both in terms of composition and relative proportion of the saponin contents in different extracts. Graphical Abstract A combination of state-of-the-art mass spectrometry methods, including ion mobility spectroscopy, is developed to afford a complete description of the saponin molecules in natural extracts
-
Mechanisms involved in pearlfish resistance to holothuroid toxins
Marine Biology, 2016Co-Authors: Lola Brasseur, Guillaume Caulier, Patrick Flammang, Pascal Gerbaux, Eric Parmentier, Maryse Vanderplanck, Denis Michez, Georges Lognay, Igor EeckhautAbstract:Holothuroids produce triterpenoid Saponins that act as chemical defenses against predators and parasites. These Saponins interact with sterols of the plasma membranes, inducing the formation of pores and then cell lysis. To avoid such harms from their own Saponins, holothuroids present specific sterols in their tissues. Despite the noxious cytotoxic effect of their chemical defenses, holothuroids host various associates that display specific adaptations to resist to saponin toxicity. Among them, symbiotic carapid fishes (i.e., pearlfishes) are resistant to ichthyotoxic Saponins as they display no stress response and a survival time 45 times longer than free-living fishes without any specific gill adaptation. The present study aims at discovering the resistance mechanism(s) developed by carapids by addressing 3 hypotheses: carapids have (1) a mechanical barrier against the toxin constituted by a larger secretion of mucus than other fishes, (2) a bioactive barrier against the toxins constituted by a mucus effective on Saponins and (3) a Δ^7sterol tissue composition mimicking holothuroids that enable them to resist to Saponins. First experiments showed that the mucus has no effective impact on saponin chemical structures. Mass spectrometry analyses showed that carapids, similarly to non-symbiotic fishes but contrary to their hosts, present a Δ^5sterol tissue composition. However, two different procedures have shown that carapids produce six to ten times more mucus than control fishes, suggesting that a great quantity of mucus can protect carapids from their host’s Saponins and acts as a mechanical barrier against toxins. Therefore, these results provide a new understanding of the carapids–holothuroids relationship.
-
Molecular diversity and body distribution of Saponins in the sea star Asterias rubens by mass spectrometry
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, 2014Co-Authors: Marie Demeyer, Julien De Winter, Guillaume Caulier, Igor Eeckhaut, Patrick Flammang, Pascal GerbauxAbstract:Saponins are natural molecules that the common sea star Asterias rubens produces in the form of steroid glycosides bearing a sulfate group attached on the aglycone part. In order to highlight the inter-organ and inter-individual variability, the saponin contents of five distinct body components, namely the aboral body wall, the oral body wall, the stomach, the pyloric caeca and the gonads, from different individuals were separately analyzed by mass spectrometry. MALDI-ToF experiments were selected as the primary tool for a rapid screening of the saponin mixtures, whereas LC-MS and LC-MS/MS techniques were used to achieve chromatographic separation of isomers. First of all, our analyses demonstrated that the diversity of Saponins is higher than previously reported. Indeed, nine new congeners were observed in addition to the 17 Saponins already described in this species. On the basis of all the collected MS/MS data, we also identified collision-induced key-fragmentations that could be used to reconstruct the molecular structure of both known and unknown saponin ions. Secondly, the comparison of the saponin contents from the five different body components revealed that each organ is characterized by a specific mixture of Saponins and that between animals there are also qualitative and quantitative variability of the saponin contents which could be linked to the sex or to the collecting season. Therefore, the observed high variability unambiguously confirms that Saponins probably fulfill several biological functions in A. rubens. The current results will pave the way for our future studies that will be devoted to the clarification of the biological roles of Saponins in A. rubens at a molecular level. © 2013 Elsevier Inc.
Nohpal Jung - One of the best experts on this subject based on the ideXlab platform.
-
korean red ginseng Saponins with low ratios of protopanaxadiol and protopanaxatriol saponin improve scopolamine induced learning disability and spatial working memory in mice
Journal of Ethnopharmacology, 1999Co-Authors: Jinkyu Park, Suenie Park, Nohpal JungAbstract:The effects of two ginseng Saponins having a different ratio of protopanaxadiol (PD) and protopanaxatriol Saponins (PT) on the learning impairment induced by scopolamine, and learning and memory in mice were investigated in a passive avoidance task and a Morris water maze task. The ratio of PD and PT was 1.24 and 1.46, respectively. Before training, the ginseng Saponins were administered intraperitoneally at doses of 50 and 100 mg/kg. The two Saponins improved the scopolamine-induced learning impairment at different dosages in mice, 50 and 100 mg/kg, respectively. However, the two Saponins did not show a favorable effect on learning and memory in normal mice. Korean red ginseng saponin with a low PD/PT ratio had an improving effect on spatial working memory, but the saponin with a high PD/PT ratio did not. This finding suggests that the PD/PT ratio of the ginseng Saponins may be an important factor in the pharmacological role of red ginseng as a medicinal herb.
Rakesh Kumar Shukla - One of the best experts on this subject based on the ideXlab platform.
-
Recent advances in steroidal Saponins biosynthesis and in vitro production
Planta, 2018Co-Authors: Swati Upadhyay, Gajendra Singh Jeena, Rakesh Kumar ShuklaAbstract:Main conclusionSteroidal Saponins exhibited numerous pharmacological activities due to the modification of their backbone by different cytochrome P450s (P450) and UDP glycosyltransferases (UGTs). Plant-derived steroidal Saponins are not sufficient for utilizing them for commercial purpose so in vitro production of saponin by tissue culture, root culture, embryo culture, etc, is necessary for its large-scale production. Saponin glycosides are the important class of plant secondary metabolites, which consists of either steroidal or terpenoidal backbone. Due to the existence of a wide range of medicinal properties, saponin glycosides are pharmacologically very important. This review is focused on important medicinal properties of steroidal saponin, its occurrence, and biosynthesis. In addition to this, some recently identified plants containing steroidal Saponins in different parts were summarized. The high throughput transcriptome sequencing approach elaborates our understanding related to the secondary metabolic pathway and its regulation even in the absence of adequate genomic information of non-model plants. The aim of this review is to encapsulate the information related to applications of steroidal saponin and its biosynthetic enzymes specially P450s and UGTs that are involved at later stage modifications of saponin backbone. Lastly, we discussed the in vitro production of steroidal saponin as the plant-based production of saponin is time-consuming and yield a limited amount of Saponins. A large amount of plant material has been used to increase the production of steroidal saponin by employing in vitro culture technique, which has received a lot of attention in past two decades and provides a way to conserve medicinal plants as well as to escape them for being endangered.
