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Patricia Valentao - One of the best experts on this subject based on the ideXlab platform.
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hplc dad esi msn phenolic profile and in vitro biological potential of Centaurium erythraea rafn aqueous extract
Food Chemistry, 2019Co-Authors: Mohamed Reda Kachmar, Patricia Valentao, Paula B Andrade, Andreia P. Oliveira, Abdelilah Ouahbi, Khalid El Badaoui, Angel Gilizquierdo, Raul Dominguezperles, Federico FerreresAbstract:Centaurium erythraea Rafn is a food flavouring used in both food and beverage industries. Despite the existence of some works on this species, only few focus their attention on its common form of consumption (infusion). Thus, we intended to explore the chemical composition and the biological properties of infusions from C. erythraea aerial parts. Phenolic compounds were identified by HPLC-DAD-ESI/MSn, twenty-two flavonoid derivatives being reported for the first time. Concerning to the biological potential, the best scavenging activity was observed for the superoxide anion radical. Moreover, this extract revealed to have some effect on the inhibition of 5-lipoxygenase, no cytotoxicity against RAW 264.7 macrophage cells line, and a weak potential to decrease the nitric oxide levels in this cell system. The results suggest that C. erythraea aerial parts could be valuable sources of health benefits compounds, contributing to its valorisation and its further application in functional foods.
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Isolation and structural elucidation of 5-formyl-2,3-dihydroisocoumarin from Centaurium erythraea aerial parts.
Natural product research, 2003Co-Authors: Patricia Valentao, Paula B Andrade, Artur M. S. Silva, M.manuela Moreira, Rosa M SeabraAbstract:An isocoumarin was isolated from the aerial parts of Centaurium erythraea Rafn. (Gentianaceae). Its structure was established by spectroscopic means as 5-formyl-2,3-dihydroisocoumarin.
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Methoxylated xanthones in the quality control of small centaury (Centaurium erythraea) flowering tops.
Journal of agricultural and food chemistry, 2002Co-Authors: Patricia Valentao, Paula B Andrade, Eurico Silva, Ana María Vicente, Henrique Santos, M. Lourdes Bastos, Rosa M SeabraAbstract:In the course of a phytochemical study of the bitter tonic plant, small centaury (Centaurium erythraea), six methoxylated xanthones (1,5-hydroxy-3-methoxyxanthone, 1-hydroxy-3,5,6-trimethoxyxanthone, 1-hydroxy-3,5,6,7-tetramethoxyxanthone, 1-hydroxy-3,5,6,7,8-pentamethoxyxanthone, 1-hydroxy-3,7,8-trimethoxyxanthone and 1,8-dihydroxy-3,5,6,7-tetramethoxyxanthone) were isolated and identified by spectroscopic means (nuclear magnetic resonance, mass spectroscopy, and UV). Subsequently, a high-performance liquid chromatography/diode array detection method was developed for the determination of these and other methoxylated xanthones occurring in the chloroform extract of small centaury aerial parts. The methodology developed was applied to twelve samples, and in all of them, nine xanthones were identified and quantified. This methodology can be considered complimentary to the one proposed by the European Pharmacopoeia.
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antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Patricia Valentao, Eduarda Fernandes, Felix Carvalho, Paula B Andrade, Rosa M Seabra, M L BastosAbstract:Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids. Keywords: Centaurium erythraea; antioxidants; polyphenol...
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Antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity.
Journal of agricultural and food chemistry, 2001Co-Authors: Patricia Valentao, Eduarda Fernandes, Felix Carvalho, Paula B Andrade, Rosa M Seabra, M.d.l. BastosAbstract:Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids.
Danijela Misic - One of the best experts on this subject based on the ideXlab platform.
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chemodiversity of two closely related tetraploid Centaurium species and their hexaploid hybrid metabolomic search for high resolution taxonomic classifiers
Phytochemistry, 2017Co-Authors: Tijana Banjanac, Branislav Siler, Jasmina Nestorovic živkovic, Milan Dragicevic, Uros Gasic, Borut Bohanec, Snežana Trifunovic, Danijela MisicAbstract:Species within the genus Centaurium readily hybridize and polyploid complexes are often seen in natural populations. We describe phytochemical profiles of newly discovered allohexaploid hybrid, here named Centaurium pannonicum, and its parental tetraploid species C. erythraea and rare C. littorale ssp. compressum. Our aim was to examine chemodiversity of these taxa in the area of Vojvodina (North Serbia) and to perform metabolomics search for chemical classifiers which would provide high resolution discrimination of parental and hybrid individuals. In sum, UHPLC-MS/MS Orbitrap metabolomics fingerprinting revealed seventy compounds in methanol extracts. Despite the lack of qualitative chemical novelty in hybrid plants, UHPLC-qqqMS targeted metabolomics approach, aimed at three secoiridoid compounds and seventeen phenolics, pointed to considerable differences in quantitative composition of these dominant compounds among the plant taxa studied. In addition to the difference in the ploidy levels, the hybrid taxon was well distinguished from both parental species based on metabolite profiles, and, for most individuals, positioned intermediately to the parental taxa in both PCA and hierarchical clustering. After optimizing and comparing several statistical learning methods, it was possible to narrow the number of taxonomic classifiers to five (three xanthones, one secoiridoid glycoside, and one phenolic acid), while increasing the differentiation resolution. The presented metabolomics approach will certainly, along with morphometrics and molecular genetics studies, have high impact on further elucidation of complex relationships among taxa within the genus Centaurium.
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biologically active compounds from the genus Centaurium s l gentianaceae current knowledge and future prospects in medicine
Studies in natural products chemistry, 2016Co-Authors: Branislav Siler, Danijela MisicAbstract:Abstract One of the plant genera with the longest tradition in human medicine history is a popular panacea, Centaurium, named according to Pliny because the plant's medicinal properties were reputedly discovered by Chiron the centaur . In 17th century, Culpeper has claimed that its inward or outward usage was so safe that no one could fail in the using of this wholesome plant. Centauries owe this tremendous quality to their secondary metabolites, terpenoid and phenolic compounds. Among them, secoiridoid glycosides are appearing as most abundant class of terpenoids, while pharmaceutically highly appreciated xanthones and flavonoids mostly represent the class of phenolics. A period of momentous exploration of these compounds in the genus Centaurium was the 1960s of the last century. In parallel, vast area of medicinal studies started to apply isolated compounds and herbal extracts, as well to investigate the principles of their positive influence to many human health issues, such as diabetes, digestive and neurological disorders, cancer, and cardiovascular diseases. In modern times, centauries and the compounds they produce still represent the subject of many medicinal and/or pharmacological studies. Their significance is highlighted by the metaanalysis: Google Scholar returns 72 academic titles (without citations), which in the same time contain either the word Centaurium or “centaury” and are dealing with some phytochemical analytics and/or medicinal aspects of herbal extracts. In only last 5 years, totally 15 studies were engaged in elucidation of medicinal or biological activity of centauries, such as antidiabetic activity—five studies; antimicrobial activity—four studies; toxicity (including cytotoxicity)—three studies; and hepatoprotective, gastroprotective, and vasodilatory effects—one study of each. Hence, there is an evident tendency and scientific interest for in-depth research on phytochemistry of the genus Centaurium s.l. and extensive insight into their modes of action to the human health. This study will offer a comprehensive and comparative overview on the secondary metabolites' analytics throughout the genus, with a contextual respect to the biotechnological enhancement of their accumulation. It will also review to-date accomplishments regarding application of various herbal extracts and isolated compounds in (bio)medicinal studies.
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secoiridoid glycosides production by Centaurium maritimum l fritch hairy root cultures in temporary immersion bioreactor
Process Biochemistry, 2013Co-Authors: Danijela Misic, Branislav Siler, Jasmina Nestorovic živkovic, Marijana Skoric, Milutin S Djurickovic, Vladan Jovanovic, Zlatko GibaAbstract:Abstract Secoiridoid glycosides are naturally occurring phytochemicals of great importance for the food and pharmaceutical industry because of their various biological activities. Certain Gentiana and Centaurium species, which are recognized as the most important sources of these compounds, have become critically endangered due to overexploitation. In this study we describe a laboratory-scale approach for further implementation in large-scale production of secoiridoid glycosides, using a hairy root culture system of Centaurium maritimum L. Fritch, an underutilized and phytochemically unexplored species. Hairy roots were induced by Agrobacterium rhizogenes strain A40M70GUS and grown in Erlenmeyer flasks, as well as in RITA ® temporary immersion bioreactors (TIBs). About 2–4 times higher biomass production rate and up to 8 times higher total secoiridoid glycosides production rate were achieved in RITA ® bioreactors. Among the selected hairy root lines, line HR3 cultured in RITA ® TIBs proved to be the most efficient considering both biomass and secoiridoid glycosides production rate.
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secoiridoid glycosides as a marker system in chemical variability estimation and chemotype assignment of Centaurium erythraea rafn from the balkan peninsula
Industrial Crops and Products, 2012Co-Authors: Branislav Siler, Tijana Banjanac, Stevan Avramov, Jelena Cvetkovic, Jasmina Nestorovic živkovic, Aleksandra Patenkovic, Danijela MisicAbstract:Abstract The content of secoiridoid glycosides in the aerial parts and roots of in vitro grown centaury ( Centaurium erythraea Rafn) plants, originating from 52 Balkan Peninsula populations was analyzed. The results of this study give insight into the infraspecific variability of centaury, based on the yield of secoiridoid glycosides as chemical markers of phenotypic variation. According to the cluster analysis, existence of two basic chemotypes is suggested. Moreover, the impact of prevailing environmental gradients in natural habitats on chemotype differentiation was assessed. The precipitation rate of the warmest quarter of year significantly affects the accumulation of secondary metabolites. These results will enable the selection of particular populations which are characterized by enhanced accumulation of secondary metabolites of interest, thus making it possible to realize the commercial field cultivation and upscale production and of this threatened and pharmacologically important species.
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the reproducibility of rapd profiles effects of pcr components on rapd analysis of four Centaurium species
Archives of Biological Sciences, 2012Co-Authors: Marijana Skoric, Branislav Siler, Danijela Misic, Tijana Banjanac, Jasmina N Zivkovic, Slavica Dmitrovic, Dragoljub GrubisicAbstract:Random amplified polymorphic DNA (RAPD) analysis is a simple and reliable method used to detect DNA polymorphism. Several factors can affect the amplification profiles, thereby causing false bands and non-reproducibility of the assay. In this study, we analyzed the effects of different concentrations of primer, magnesium chloride, template DNA and Taq DNA polymerase to develop and standardize a RAPD protocol for Centaurium species. The optimized PCR reaction mixture included: 50 ng of DNA extracted using a CTbased protocol, 2.5 mM MgCl2, 7.5 pmol primer and 2 U of Taq polymerase in a final volume of 25 μl. Each of the five primers used in experiments (OPB11, OPB15, OPB18, OPF05 and OPH02) generated reproducible and distinguishable fingerprinting patterns of four Centaurium species. The obtained optimized RAPD protocol and the selected primers are useful for our further work in the genetic diversity studies of Centaurium species.
Branislav Siler - One of the best experts on this subject based on the ideXlab platform.
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Centaurium erythraea extract reduces redox imbalance and improves insulin expression and secretion in pancreatic β-cells exposed to oxidative and nitrosative stress
Archives of Biological Sciences, 2020Co-Authors: Miloš Đorđević, Danijela Mišić, Nevena Grdović, Mirjana Mihailović, Jelena Jovanovic, Aleksandra Uskoković, Jovana Rajić, Marija Prekajski Đorđević, Anja Tolić, Branislav SilerAbstract:Paper description: Oxidative stress underlies b-cell damage and a diminished capacity for insulin secretion in diabetes. Previously we have shown that the Centaurium erythraea extract (CEe) exhibits a significant redox potential both in vitro and in an animal model of diabetes. Herein we examined the antioxidant effects of CEe in H 2 O 2 -and sodium nitroprusside (SNP)-treated Rin-5F b-cells. CEe attenuated the H 2 O 2 - and SNP-induced redox imbalance, contributing to a decrease in DNA, lipid and protein damage and to an increase in cell-viability and insulin expression and secretion. Abstract: Oxidative stress is one of the major mechanisms that underlies the damage of pancreatic b-cells and defects in insulin secretion in diabetes. As herbal preparations can alleviate oxidative stress through their redox-active secondary metabolites, in this study we investigated the cytoprotective effects of Centaurium erythraea extract (CEe) against H 2 O 2 - and SNP-induced oxidative/nitrosative stress in Rin-5F b-cells. The antioxidant activity of CEe and its effect on cell survival and insulin expression/secretion were evaluated. The CEe increased cell viability and ameliorated the disturbance of redox homeostasis in H 2 O 2 - and SNP-treated cells by decreasing DNA damage, lipid peroxidation and protein S-glutathionylation. The CEe restored GSH homeostasis in H 2 O 2 -treated b-cells and attenuated the SNP-induced disturbance of the GSH/GSSG ratio. The H 2 O 2 - and SNP-induced disruption of CAT, GPx, GR, MnSOD and CuZnSOD activities was adjusted by the CEe towards control values, as well as mRNA and protein levels of GPx, MnSOD and CAT. The CEe increased insulin expression/secretion particularly in H 2 O 2 -treated b-cells, which was in accordance with the more pronounced antioxidant effect of the CEe observed in H 2 O 2 -treated b-cells as compared to SNP-treated cells. These findings support the beneficial effect of the CEe in preventing or slowing down b-cell damage and dysfunction caused by oxidative/nitrosative stress during diabetes development. https://doi.org/10.2298/ABS200127005D Received: January 27, 2020; Revised: January 31, 2020; Accepted: January 31, 2020; Published online: February 10, 2020 How to cite this article: Đorđevic M, Grdovic N, Mihailovic M, Arambasic Jovanovic J, Uskokovic A, Rajic J, Đorđevic M, Tolic A, Misic D, Siler B, Poznanovic G, Vidakovic M, Dinic S. Centaurium erythraea extract reduces redox imbalance and improves insulin expression and secretion in pancreatic β-cells exposed to oxidative and nitrosative stress. Arch Biol Sci. 2020;72(1):117-28.
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chemodiversity of two closely related tetraploid Centaurium species and their hexaploid hybrid metabolomic search for high resolution taxonomic classifiers
Phytochemistry, 2017Co-Authors: Tijana Banjanac, Branislav Siler, Jasmina Nestorovic živkovic, Milan Dragicevic, Uros Gasic, Borut Bohanec, Snežana Trifunovic, Danijela MisicAbstract:Species within the genus Centaurium readily hybridize and polyploid complexes are often seen in natural populations. We describe phytochemical profiles of newly discovered allohexaploid hybrid, here named Centaurium pannonicum, and its parental tetraploid species C. erythraea and rare C. littorale ssp. compressum. Our aim was to examine chemodiversity of these taxa in the area of Vojvodina (North Serbia) and to perform metabolomics search for chemical classifiers which would provide high resolution discrimination of parental and hybrid individuals. In sum, UHPLC-MS/MS Orbitrap metabolomics fingerprinting revealed seventy compounds in methanol extracts. Despite the lack of qualitative chemical novelty in hybrid plants, UHPLC-qqqMS targeted metabolomics approach, aimed at three secoiridoid compounds and seventeen phenolics, pointed to considerable differences in quantitative composition of these dominant compounds among the plant taxa studied. In addition to the difference in the ploidy levels, the hybrid taxon was well distinguished from both parental species based on metabolite profiles, and, for most individuals, positioned intermediately to the parental taxa in both PCA and hierarchical clustering. After optimizing and comparing several statistical learning methods, it was possible to narrow the number of taxonomic classifiers to five (three xanthones, one secoiridoid glycoside, and one phenolic acid), while increasing the differentiation resolution. The presented metabolomics approach will certainly, along with morphometrics and molecular genetics studies, have high impact on further elucidation of complex relationships among taxa within the genus Centaurium.
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biologically active compounds from the genus Centaurium s l gentianaceae current knowledge and future prospects in medicine
Studies in natural products chemistry, 2016Co-Authors: Branislav Siler, Danijela MisicAbstract:Abstract One of the plant genera with the longest tradition in human medicine history is a popular panacea, Centaurium, named according to Pliny because the plant's medicinal properties were reputedly discovered by Chiron the centaur . In 17th century, Culpeper has claimed that its inward or outward usage was so safe that no one could fail in the using of this wholesome plant. Centauries owe this tremendous quality to their secondary metabolites, terpenoid and phenolic compounds. Among them, secoiridoid glycosides are appearing as most abundant class of terpenoids, while pharmaceutically highly appreciated xanthones and flavonoids mostly represent the class of phenolics. A period of momentous exploration of these compounds in the genus Centaurium was the 1960s of the last century. In parallel, vast area of medicinal studies started to apply isolated compounds and herbal extracts, as well to investigate the principles of their positive influence to many human health issues, such as diabetes, digestive and neurological disorders, cancer, and cardiovascular diseases. In modern times, centauries and the compounds they produce still represent the subject of many medicinal and/or pharmacological studies. Their significance is highlighted by the metaanalysis: Google Scholar returns 72 academic titles (without citations), which in the same time contain either the word Centaurium or “centaury” and are dealing with some phytochemical analytics and/or medicinal aspects of herbal extracts. In only last 5 years, totally 15 studies were engaged in elucidation of medicinal or biological activity of centauries, such as antidiabetic activity—five studies; antimicrobial activity—four studies; toxicity (including cytotoxicity)—three studies; and hepatoprotective, gastroprotective, and vasodilatory effects—one study of each. Hence, there is an evident tendency and scientific interest for in-depth research on phytochemistry of the genus Centaurium s.l. and extensive insight into their modes of action to the human health. This study will offer a comprehensive and comparative overview on the secondary metabolites' analytics throughout the genus, with a contextual respect to the biotechnological enhancement of their accumulation. It will also review to-date accomplishments regarding application of various herbal extracts and isolated compounds in (bio)medicinal studies.
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Interspecific in vitro hybridization in genus Centaurium and identification of hybrids via flow cytometry, RAPD, and secondary metabolite profiles
TURKISH JOURNAL OF BOTANY, 2014Co-Authors: Tijana Banjanac, Branislav Siler, Marijana Skorić, Nabil GhalawenjiAbstract:Most of the species from the genus Centaurium Hill readily hybridize between themselves in natural habitats. Artificial interspecific hybrid plants were obtained under in vitro conditions using reciprocal crosses between 4 species: Centaurium erythraea, C. littorale, C. maritimum, and C. pulchellum. Among 76 crossing experiments performed, 3 types of crosses produced seeds and gave 20 interspecific hybrid plants. Nuclear DNA quantification, fingerprinting of molecular markers, and determination of variation in main secondary metabolite content were employed to confirm their hybrid nature. All 3 approaches were capable of detecting hybrid plants. RAPD molecular markers proved to be the most reliable, always placing the hybrids between their parents in dendrograms, while secoiridoid glycoside content also showed intermediate profiles in the hybrid plants in relation to the parents. Hence, each of the techniques employed can be recommended for elucidating the mechanisms of interspecific hybridization in natural populations of Centaurium species in further studies. This could help to comprehend their breeding system and recognize interspecific hybridization as one of the crucial steps in polyploid formation and speciation in this genus.
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secoiridoid glycosides production by Centaurium maritimum l fritch hairy root cultures in temporary immersion bioreactor
Process Biochemistry, 2013Co-Authors: Danijela Misic, Branislav Siler, Jasmina Nestorovic živkovic, Marijana Skoric, Milutin S Djurickovic, Vladan Jovanovic, Zlatko GibaAbstract:Abstract Secoiridoid glycosides are naturally occurring phytochemicals of great importance for the food and pharmaceutical industry because of their various biological activities. Certain Gentiana and Centaurium species, which are recognized as the most important sources of these compounds, have become critically endangered due to overexploitation. In this study we describe a laboratory-scale approach for further implementation in large-scale production of secoiridoid glycosides, using a hairy root culture system of Centaurium maritimum L. Fritch, an underutilized and phytochemically unexplored species. Hairy roots were induced by Agrobacterium rhizogenes strain A40M70GUS and grown in Erlenmeyer flasks, as well as in RITA ® temporary immersion bioreactors (TIBs). About 2–4 times higher biomass production rate and up to 8 times higher total secoiridoid glycosides production rate were achieved in RITA ® bioreactors. Among the selected hairy root lines, line HR3 cultured in RITA ® TIBs proved to be the most efficient considering both biomass and secoiridoid glycosides production rate.
Paula B Andrade - One of the best experts on this subject based on the ideXlab platform.
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hplc dad esi msn phenolic profile and in vitro biological potential of Centaurium erythraea rafn aqueous extract
Food Chemistry, 2019Co-Authors: Mohamed Reda Kachmar, Patricia Valentao, Paula B Andrade, Andreia P. Oliveira, Abdelilah Ouahbi, Khalid El Badaoui, Angel Gilizquierdo, Raul Dominguezperles, Federico FerreresAbstract:Centaurium erythraea Rafn is a food flavouring used in both food and beverage industries. Despite the existence of some works on this species, only few focus their attention on its common form of consumption (infusion). Thus, we intended to explore the chemical composition and the biological properties of infusions from C. erythraea aerial parts. Phenolic compounds were identified by HPLC-DAD-ESI/MSn, twenty-two flavonoid derivatives being reported for the first time. Concerning to the biological potential, the best scavenging activity was observed for the superoxide anion radical. Moreover, this extract revealed to have some effect on the inhibition of 5-lipoxygenase, no cytotoxicity against RAW 264.7 macrophage cells line, and a weak potential to decrease the nitric oxide levels in this cell system. The results suggest that C. erythraea aerial parts could be valuable sources of health benefits compounds, contributing to its valorisation and its further application in functional foods.
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Isolation and structural elucidation of 5-formyl-2,3-dihydroisocoumarin from Centaurium erythraea aerial parts.
Natural product research, 2003Co-Authors: Patricia Valentao, Paula B Andrade, Artur M. S. Silva, M.manuela Moreira, Rosa M SeabraAbstract:An isocoumarin was isolated from the aerial parts of Centaurium erythraea Rafn. (Gentianaceae). Its structure was established by spectroscopic means as 5-formyl-2,3-dihydroisocoumarin.
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Methoxylated xanthones in the quality control of small centaury (Centaurium erythraea) flowering tops.
Journal of agricultural and food chemistry, 2002Co-Authors: Patricia Valentao, Paula B Andrade, Eurico Silva, Ana María Vicente, Henrique Santos, M. Lourdes Bastos, Rosa M SeabraAbstract:In the course of a phytochemical study of the bitter tonic plant, small centaury (Centaurium erythraea), six methoxylated xanthones (1,5-hydroxy-3-methoxyxanthone, 1-hydroxy-3,5,6-trimethoxyxanthone, 1-hydroxy-3,5,6,7-tetramethoxyxanthone, 1-hydroxy-3,5,6,7,8-pentamethoxyxanthone, 1-hydroxy-3,7,8-trimethoxyxanthone and 1,8-dihydroxy-3,5,6,7-tetramethoxyxanthone) were isolated and identified by spectroscopic means (nuclear magnetic resonance, mass spectroscopy, and UV). Subsequently, a high-performance liquid chromatography/diode array detection method was developed for the determination of these and other methoxylated xanthones occurring in the chloroform extract of small centaury aerial parts. The methodology developed was applied to twelve samples, and in all of them, nine xanthones were identified and quantified. This methodology can be considered complimentary to the one proposed by the European Pharmacopoeia.
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antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity
Journal of Agricultural and Food Chemistry, 2001Co-Authors: Patricia Valentao, Eduarda Fernandes, Felix Carvalho, Paula B Andrade, Rosa M Seabra, M L BastosAbstract:Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids. Keywords: Centaurium erythraea; antioxidants; polyphenol...
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Antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity.
Journal of agricultural and food chemistry, 2001Co-Authors: Patricia Valentao, Eduarda Fernandes, Felix Carvalho, Paula B Andrade, Rosa M Seabra, M.d.l. BastosAbstract:Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids.
Ludger Beerhues - One of the best experts on this subject based on the ideXlab platform.
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3-Hydroxybenzoate:coenzyme A ligase from cell cultures of Centaurium erythraea: isolation and characterization.
Biological chemistry, 2000Co-Authors: Wagner Barillas, Ludger BeerhuesAbstract:In xanthone biosynthesis, 3-hydroxybenzoate:coenzyme A ligase (3HBL) supplies the starter substrate for the formation of an intermediate benzophenone. 3HBL from cell cultures of the medicinal plant Centaurium erythraea was purified to apparent homogeneity using a seven-step-procedure. The enzyme was an AMP-forming CoA ligase with a Km = 14.7 microM for 3-hydroxybenzoic acid, 8.5 microM for coenzyme A and 229 microM for ATP. The pH and temperature optima were 7.5 and 35 degrees C, respectively. In SDS-PAGE, two polypeptides of Mr 41,500 and 40,500 were detected. Both proteins were structurally related to each other as shown by tryptic digestion. Their N-termini were blocked. The difference in their apparent molecular masses could not be attributed to glycosylation. 3HBL had a native Mr of approx. 50,000 and is thus active as a monomer.
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Xanthone 6-hydroxylase from cell cultures of Centaurium erythraea RAFN and Hypericum androsaemum L.
Phytochemistry, 2000Co-Authors: W Schmidt, Stefan Peters, Ludger BeerhuesAbstract:Xanthone 6-hydroxylase activity was detected in the microsomal fractions from two plant cell cultures. The enzyme from cultured cells of Centaurium erythraea (Gentianaceae) exhibited absolute specificity for 1,3,5-trihydroxyxanthone as substrate, whereas xanthone 6-hydroxylase from cell cultures of Hypericum androsaemum (Hypericacaea) preferred the isomeric 1,3,7-trihydroxyxanthone but used 1,3,5-trihydroxyxanthone also to a small extent. Both xanthones were regioselectively hydroxylated in position 6. The xanthone 6-hydoxylases are cytochrome P450 monooxygenases, as shown by their dependence on NADPH and molecular oxygen and their inhibition by carbon monoxide and typical P450 inhibitors. In both cell cultures, xanthone accumulation was preceded by an increase in xanthone 6-hydroxylase activity.
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3-Hydroxybenzoate:coenzyme A ligase and 4-coumarate:coenzyme A ligase from cultured cells of Centaurium erythraea.
Planta, 1997Co-Authors: Wagner Barillas, Ludger BeerhuesAbstract:3-Hydroxybenzoate:coenzyme A ligase, an enzyme involved in xanthone biosynthesis, was detected in cell-free extracts from cultured cells of Centaurium erythraea Rafn. The enzyme was separated from 4-coumarate:coenzyme A ligase by fractionated ammonium sulphate precipitation and hydrophobic interaction chromatography. The CoA ligases exhibited different substrate specificities. 3-Hydroxybenzoate:coenzyme A ligase activated 3-hydroxybenzoic acid most efficiently and lacked affinity for cinnamic acids. In contrast, 4-coumarate:CoA ligase mainly catalyzed the activation of 4-coumaric acid but did not act on benzoic acids. The two enzymes were similar with respect to their relative molecular weight, their pH and temperature optima, their specific activity and the changes in their activity during cell culture growth.
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Benzophenone synthase from cultured cells of Centaurium erythraea
FEBS letters, 1996Co-Authors: Ludger BeerhuesAbstract:A central step in xanthone biosynthesis is the formation of the C13 skeleton, i.e. an intermediate benzophenone. Biosynthesis of 2,3′,4,6-tetrahydroxybenzophenone from m-hydroxybenzoyl-CoA and malonyl-CoA was shown in cell-free extracts from cultured cells of Centaurium erythraea. The enzyme catalyzing this reaction was named benzophenone synthase.
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Differential accumulation of xanthones in methyl-jasmonate- and yeast-extract-treated cell cultures of Centaurium erythraea and Centaurium littorale
Planta, 1995Co-Authors: Ludger Beerhues, Ursel BergerAbstract:Cell-suspension cultures of Centaurium erythraea and Centaurium littorale (Gentianaceae) respond to methyl jasmonate and yeast extract with a differential accumulation of xanthones. Methyl jasmonate induced the formation of 1-hydroxy-3,5,6,7-tetramethoxyxanthone, the amount of which increased in both cell cultures around 10 h after addition. A substantial increase in the activity of phenylalanine ammonia-lyase (PAL) was not observed. When challenged with yeast extract the cell cultures accumulated l,5-dihydroxy-3-methoxyxanthone. This appeared rapidly after addition of yeast extract in C. erythraea but its amount in C. littorale increased only after a lag phase of 25 h. While PAL activity in C. erythraea was strongly suppressed a fourfold increase in its activity was found in C. littorale . Both elicited xanthones accumulated intracellularly. A scheme for xanthone biosynthesis in the two cell cultures is proposed.