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Phytochemistry - published by Elsevier
Phytochemistry is the international journal of pure and applied plant chemistry, plant biochemistry and molecular biology.
Publication year: 2012 Source:Phytochemistry, Volume 78 Philip C. Stevenson, Geoffrey C. Kite, Gwilym P. Lewis, Félix Forest, Stephen P. Nyirenda, Steven R. Belmain, Gudeta W. Sileshi, Nigel C. Veitch Tephrosia vogelii Hook. f. (Leguminosae) is being promoted as a pest control and soil enrichment agent for poorly-resourced small-scale farmers in southern and eastern Africa. This study examined plants being cultivated by farmers and found two chemotypes. Chemotype 1 (C1) contained rotenoids, including deguelin, rotenone, sarcolobine, tephrosin and ?-toxicarol, required for pest control efficacy. Rotenoids were absent from chemotype 2 (C2), which was characterised by prenylated flavanones, including the previously unrecorded examples (2S)-5,7-dimethoxy-8-(3-hydroxy-3-methylbut-1Z-enyl)flavanone, (2S)-5,7-dimethoxy-8-(3-methylbut-1,3-dienyl)flavanone, (2S)-4?-hydroxy-5-methoxy-6?,6?-dimethylpyrano[2?,3?:7,8]flavanone, (2S)-5-methoxy-6?,6?-dimethyl-4?,5?-dihydrocyclopropa[4?,5?]furano[2?,3?:7,8]flavanone, (2S)-7-hydroxy-5-methoxy-8-prenylflavanone, and (2R,3R)-3-hydroxy-5-methoxy-6?,6?-dimethylpyrano[2?,3?:7,8]flavanone. The known compounds (2S)-5-methoxy-6?,6?-dimethylpyrano[2?,3?:7,8]flavanone (obovatin 5-methyl ether) and 5,7-dimethoxy-8-(3-hydroxy-3-methylbut-1Z-enyl)flavone (Z-tephrostachin) were also found in C2. This chemotype, although designated Tephrosia candida DC. in collections originating from the World Agroforestry Centre (ICRAF), was confirmed to be T. vogelii on the basis of morphological comparison with verified herbarium specimens and DNA sequence analysis. Sampling from 13 locations in Malawi where farmers cultivate Tephrosia species for insecticidal use indicated that almost 1 in 4 plants were T. vogelii C2, and so were unsuitable for this application. Leaf material sourced from a herbarium specimen of T. candida contained most of the flavanones found in T. vogelii C2, but no rotenoids. However, the profile of flavonol glycosides was different to that of T. vogelii C1 and C2, with 6-hydroxy-kaempferol 6-methyl ether as the predominant aglycone rather than kaempferol and quercetin. The structures of four unrecorded flavonol glycosides present in T. candida were determined using cryoprobe NMR spectroscopy and MS as the 3-O-?-rhamnopyranosyl(1?6)-?-galactopyranoside-7-O-?-rhamnopyranoside, 3-O-?-rhamnopyranosyl(1?2)[?-rhamnopyranosyl(1?6)]-?-galactopyranoside, 3-O-?-rhamnopyranosyl(1?2)[?-rhamnopyranosyl(1?6)]-?-galactopyranoside-7-O-?-rhamnopyranoside, and 3-O-?-rhamnopyranosyl(1?2)[(3-O-E-feruloyl)-?-rhamnopyranosyl(1?6)]-?-galactopyranosides of 6-hydroxykaempferol 6-methyl ether. Tentative structures for a further 37 flavonol glycosides of T. candida were assigned by LC–MS/MS. The correct chemotype of T. vogelii (i.e. C1) needs to be promoted for use by farmers in pest control applications.
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Two chemotypes of Tephrosia vogelii were distinguished based on the occurrence of either rotenoids or flavanones in their leaves. These findings have implications for pest control applications.? Two chemotypes of Tephrosia vogelii characterised by presence or absence of rotenoids. ? Chemotype 2 lacks rotenoids but contains five new flavanones and a new dihydroflavonol. ? More than 20% field-collected specimens in Malawi were non-pesticidal chemotype 2. ? Some field-grown material incorrectly designated as Tephrosia candida instead of T. vogelii. ? Flavonoid profiling of T. candida herbarium material revealed many new glycosides.
Publication year: 2012 Source:Phytochemistry LeeCole L. Legette, Arlyn Y. Moreno Luna, Ralph L. Reed, Cristobal L. Miranda, Gerd Bobe, Rosita R. Proteau, Jan F. Stevens Obesity contributes to increased risk for several chronic diseases including cardiovascular disease and type 2 diabetes. Xanthohumol, a prenylated flavonoid from hops (Humulus lupulus), was tested for efficacy on biomarkers of metabolic syndrome in 4week old Zucker fa/fa rats, a rodent model of obesity. Rats received daily oral doses of xanthohumol at 0, 1.86, 5.64, and 16.9mg/kg BW for 6weeks. All rats were maintained on a high fat (60% kcal) AIN-93G diet for 3weeks to induce severe obesity followed by a normal AIN-93G (15% kcal fat) diet for the last 3weeks of the study. Weekly food intake and body weight were recorded. Plasma cholesterol, glucose, insulin, triglyceride, and monocyte chemoattractant protein-1 (MCP-1) levels were assessed using commercial assay kits. Plasma and liver tissue levels of XN and its metabolites were determined by liquid–chromatography tandem mass spectrometry. Plasma and liver tissue levels of xanthohumol were similar between low and medium dose groups and significantly (p<0.05) elevated in the highest dose group. There was a dose-dependent effect on body weight and plasma glucose levels. The highest dose group (n=6) had significantly lower plasma glucose levels compared to the control group (n=6) in male but not female rats. There was also a significant decrease in body weight for male rats in the highest dose group (16.9mg/kg BW) compared to rats that received no xanthohumol, which was also not seen for female rats. Plasma cholesterol, insulin, triglycerides, and MCP-1 as well as food intake were not affected by treatment. The findings suggest that xanthohumol has beneficial effects on markers of metabolic syndrome.
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Daily administration of xanthohumol (16.9mg/kg) for 6weeks resulted in lower body weight and lower fasting plasma glucose in obese male but not in female Zucker fa/fa rats.? Zucker fa/fa rats were treated with xanthohumol from hops for 6weeks. ? Xanthohumol lowered fasting plasma glucose in male animals at a dose of 16.9mg/kg. ? Xanthohumol lowered body weight in male animals at a dose of 16.9mg/kg. ? Steady-state plasma and liver tissue levels of xanthohumol agree with dose–effect relationships.
Publication year: 2012 Source:Phytochemistry, Volume 77 Scott C. Farrow, Jillian M. Hagel, Peter J. Facchini Benzylisoquinoline alkaloids (BIAs) are a large and diverse group of ?2500 specialized metabolites found predominantly in plants of the order Ranunculales. Research focused on BIA metabolism in a restricted number of plant species has identified many enzymes and cognate genes involved in the biosynthesis of compounds such as morphine, sanguinarine and berberine. However, the formation of most BIAs remains uncharacterized at the molecular biochemical level. Herein a compendium of sequence- and metabolite-profiling resources from 18 species of BIA-accumulating cell cultures was established, representing four related plant families. Our integrated approach consisted of the construction of EST libraries each containing approximately 3500 unigenes per species for a total of 58,787 unigenes. The EST libraries were manually triaged using known BIA-biosynthetic genes as queries to identify putative homologs with similar or potentially different functions. Sequence resources were analyzed in the context of the targeted metabolite profiles obtained for each cell culture using electrospray-ionization and collision-induced dissociation mass spectrometry. Fragmentation analysis was used for the identification or structural characterization coupled with the relative quantification of 72 BIAs, which establishes a key resource for future work on alkaloid biosynthesis. The metabolite profile obtained for each species provides a rational basis for the prediction of enzyme function in BIA metabolism. The metabolic frameworks assembled through the integration of transcript and metabolite profiles allow a comparison of BIA metabolism across several plant species and families. Taken together, these data represent an important tool for the discovery of BIA biosynthetic genes.
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Integration of expressed sequence tag and targeted metabolite profile databases for cell cultures of 18 plant species provides a repository of candidate biosynthetic genes involved in benzylisoquinoline alkaloid metabolism.? We established EST and metabolomics resources for 18 alkaloid-accumulating cell cultures. ? Our EST libraries contain ?3500 unigenes per species for a total of 58,787 unigenes. ? More than 250 putative biosynthetic gene candidates were identified with potential functions. ? Mass spectrometry was used to identify and quantify 72 alkaloids. ? Metabolite profiles provide a rational basis predicting the function of novel enzymes.
Publication year: 2012 Source:Phytochemistry, Volume 78 Juan J. Araya, Franklin Binns, Kelly Kindscher, Barbara N. Timmermann As part of our ongoing effort to explore the chemical diversity of plants of the United States Midwest region, the isolation and identification of 13 pregnane glycosides named verticillosides A–M from Asclepias verticillata L. are reported. The structures of these compounds were elucidated by various spectroscopic techniques, including 1D and 2D NMR, IR, UV, and HRMS. The cytotoxicity of the isolates was evaluated against paired breast cell lines Hs578T (cancer) and Hs578Bst (normal), however, no significant growth inhibition was observed.
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Isolation and identification of 13 pregnane glycosides named verticillosides A–M from Asclepias verticillata L.? Verticillosides A–M, 13 pregnane glycosides, were isolated from Asclepias verticillata L. ? 800 MHz NMR experiments and X-ray crystallography were employed for structure elucidation. ? Isolates did not show significant cytotoxicity against breast cancer cell line Hs578T.
Publication year: 2012 Source:Phytochemistry, Volume 78 Hung-Yi Huang, Horng-Huey Ko, Yu-Jin Jin, Sheng-Zehn Yang, You-An Shih, Ih-Sheng Chen Bioassay-guided fractionation of the roots of Anneslea fragrans var. lanceolata led to the isolation of four dihydrochalcone glucosides, davidigenin-2?-O-(6?-O-4??-hydroxybenzoyl)-?-glucoside (1), davidigenin-2?-O-(2?-O-4??-hydroxybenzoyl)-?-glucoside (2), davidigenin-2?-O-(3?-O-4??-hydroxybenzoyl)-?-glucoside (3), and davidigenin-2?-O-(6?-O-syringoyl)-?-glucoside (4), and 13 known compounds. The structures were identified by means of spectroscopic analysis. Davidigenin-2?-O-(6?-O-syringoyl)-?-glucoside (4), 1-O-3,4-dimethoxy-5-hydroxyphenyl-6-O-(3,5-di-O-methylgalloyl)-?-glucopyranoside (5), lyoniresinol (10), and syringic acid (13) showed ABTS [2,2?-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] cation radical scavenging activity, with SC50 values of 52.6±5.5, 26.0±0.7, 6.0±0.2, and 27.5±0.6?g/mL in 20min, respectively. Lyoniresinol (10), isofraxidin (12), and syringic acid (13) also showed DPPH [1,1-diphenyl-2-picrylhydrazyl] radical scavenging activity, with SC50 values of 8.4±1.8, 51.6±2.2, and 4.3±0.7?g/mL in 30min, respectively.
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Dihydrochalcone glucosides below and 13 known compounds were isolated from the roots of Anneslea fragrans var. lanceolata, and their structures determined by spectroscopic analysis.? Dihydrochalcone glucosides were isolated from A. fragrans var. lanceolata. ? These being previously unknown in the Theaceae. ? Other known compounds showed ABTS cation radical scavenging activity, and/or DPPH radical scavenging activity.
Publication year: 2012 Source:Phytochemistry, Volume 78 Pieter B. Venter, Nadine D. Senekal, Maryam Amra-Jordaan, Susan L. Bonnet, Jan H. Van der Westhuizen Proanthocyanidins (PACs) are natural plant-derived polymers used in leather tanning, wood adhesives, water purification, and mud additives for oil drilling. Quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood and mimosa (Acacia mearnsii) bark extracts are the major industrial sources of PACs. These commercial extracts are often sulfited via treatment with sodium hydrogen sulfite to reduce their viscosity and increase their solubility in water. An ESI-MS investigation into the molecular composition of sulfited (cold-water-soluble) quebracho heartwood extract indicates that sulfitation of the PACs occurs via SN2 attack of a sulfite ion at both C-2 and C-4 of the constituent flavan-3-ol monomer extender units. Attack at C-2 leads to the opening of the pyran ring. This releases an additional electron-donating phenolic hydroxy group on the A-ring and renders the extract more nucleophilic and suitable for the manufacturing of adhesives. Attack at C-4 leads to interflavanyl bond fission and decrease of the PAC oligomer chain length. The introduction of sulfonic acid moieties at C-2 or C-4 increases the polarity and water solubility of the hot water soluble (unsulfited) extract and transforms it into a cold-water-soluble extract.
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The chemical changes that take place upon extraction of quebracho proanthocyanidins with bisulfite (sulfitation) were investigated with electrospray mass spectrometry. Sulfonic acid moieties are introduced on both the C-2 and C-4 positions, changing certain physical properties such as water solubility, and enhancing the suitability of the natural extract for industrial applications. C-4 sulfitation is accompanied by interflavanyl bond fission and a reduced average chain length.? An ESI investigation into the composition of sulfited quebracho proanthocyanidins. ? Extraction with bisulfite leads to the introduction of sulfonic acid moieties. ? C-4 sulfitation breaks interflavanyl bonds and reduces chain length. ? C-2 sulfitation opens the pyran ring and increases water solubility. ? A chromatographic method to separate and quantify sulfited and non-sulfited PACs.
Publication year: 2012 Source:Phytochemistry, Volume 78 Ai-Ling Kao, Ying-Han Lin, Rita P.-Y. Chen, Yun-Yen Huang, Ching-Chung Chen, Chien-Chih Yang AtMAPR5/MSBP1 and its homologs can be ubiquitinated in the absence of E3 ligase in in vitro ubiquitination assays. Ubiquitinated AtMAPR3, AtMAPR5/MSBP1, and AtMAPR2 were identified using LC–MS/MS. Analysis of trypsin-released signature peptides showed that this E3-independent ubiquitination of AtMAPR3, AtMAPR5/MSBP1, and AtMAPR2 was dominated by mono-ubiquitination at multiple sites. Unlike AtUBC8-type E2s, AtUBC36 was not able to transfer ubiquitin to AtMAPR2. The truncated mutants AtMAPR2?1–10, AtMAPR2?1–30, and AtMAPR2_1–73 could also be ubiquitinated. The presence of a ubiquitin-binding domain (UBD) allows proteins to be ubiquitinated independently of E3 ligases. However, AtMAPRs do not contain any known UBD. In vitro ubiquitination of AtMAPR2 observed in this study will be further studied in biochemical and physiological aspects.
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AtMAPR5/MSBP1 and its homologs can be ubiquitinated in the absence of E3 ligase in in vitro ubiquitination assays. Ubiquitinated AtMAPR3 and AtMAPR5/MSBP1 were identified using LC–MS/MS. Representative MS/MS spectra showing the signature peptide Gly–Gly tag on Lys residue of ubiquitinated-AtMAPR3.? First report of the E3-independent ubiquitination of a plant-derived protein. ? Multiple E2s have the ability to ubiquitinate AtMAPR2. ? This ubiquitination reaction was dominated by mono-ubiquitination at multiple sites.
Publication year: 2012 Source:Phytochemistry Matthias P. Krajewski, Basem Kanawati, Agnes Fekete, Natalie Kowalski, Philippe Schmitt-Kopplin, Erwin Grill The genome of Arabidopsis thaliana encodes 54 functional glutathione transferases (GSTs), classified in seven clades. Although plant GSTs have been implicated in the detoxification of xenobiotics, such as herbicides, extensive redundancy within this large gene family impedes a functional analysis in planta. In this study, a GST-deficient yeast strain was established as a system for analyzing plant GSTs that allows screening for GST substrates and identifying substrate preferences within the plant GST family. To this end, five yeast genes encoding GSTs and GST-related proteins were simultaneously disrupted. The resulting yeast quintuple mutant showed a strongly reduced conjugation of the GST substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl). Consistently, the quintuple mutant was hypersensitive to CDNB, and this phenotype was complemented by the inducible expression of Arabidopsis GSTs. The conjugating activity of the plant GSTs was assessed by in vitro enzymatic assays and via analysis of exposed yeast cells. The formation of glutathione adducts with dinitrobenzene was unequivocally verified by stable isotope labeling and subsequent accurate ultrahigh-resolution mass spectrometry (ICR-FTMS). Analysis of Arabidopsis GSTs encompassing six clades and 42 members demonstrated functional expression in yeast by using CDNB and NBD-Cl as model substrates. Subsequently, the established yeast system was explored for its potential to screen the Arabidopsis GST family for conjugation of the fungicide anilazine. Thirty Arabidopsis GSTs were identified that conferred increased levels of glutathionylated anilazine. Efficient anilazine conjugation was observed in the presence of the phi, tau, and theta clade GSTs including AtGSTF2, AtGSTF4, AtGSTF6, AtGSTF8, AtGSTF10, and AtGSTT2, none of which had previously been known to contribute to fungicide detoxification. ICR-FTMS analysis of yeast extracts allowed the simultaneous detection and semiquantification of anilazine conjugates as well as catabolites.
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Protein family-wide analysis of Arabidopsis GSTs in yeast showed a widespread capacity to conjugate the fungicide anilazine including members of the phi, tau, and theta clade of plant GSTs.? Glutathione-transferase deficient yeast strains. ? Analysis of Arabidopsis glutathione-transferase family. ? Detoxification of 1-chloro-2,4-dichlorobenzene and 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl). ? Fungicide conjugation to glutathione by GSTs of the phi, tau, and theta clade.
Publication year: 2012 Source:Phytochemistry Jillian Collins-Silva, Aise Taban Nural, Amanda Skaggs, Deborah Scott, Upul Hathwaik, Rebekah Woolsey, Kathleen Schegg, Colleen McMahan, Maureen Whalen, Katrina Cornish, David Shintani Several proteins have been identified and implicated in natural rubber biosynthesis, one of which, the small rubber particle protein (SRPP), was originally identified in Hevea brasiliensis as an abundant protein associated with cytosolic vesicles known as rubber particles. While previous in vitro studies suggest that SRPP plays a role in rubber biosynthesis, in vivo evidence is lacking to support this hypothesis. To address this issue, a transgene approach was taken in Taraxacum kok-saghyz (Russian dandelion or Tk) to determine if altered SRPP levels would influence rubber biosynthesis. Three dandelion SRPPs were found to be highly abundant on dandelion rubber particles. The most abundant particle associated SRPP, TkSRPP3, showed temporal and spatial patterns of expression consistent with patterns of natural rubber accumulation in dandelion. To confirm its role in rubber biosynthesis, TkSRPP3 expression was altered in Russian dandelion using over-expression and RNAi methods. While TkSRPP3 over-expressing lines had slightly higher levels of rubber in their roots, relative to the control, TkSRPP3 RNAi lines showed significant decreases in root rubber content and produced dramatically lower molecular weight rubber than the control line. Not only do results here provide in vivo evidence of TkSRPP proteins affecting the amount of rubber in dandelion root, but they also suggest a function in regulating the molecular weight of the cis-1, 4-polyisoprene polymer.
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RNAi knockdown of the small rubber particle protein 3 (TkSRPP3) in Taraxacum kok-saghyz causes a large decrease in the molecular weight of rubber in roots, indicating a role for SRPPs in regulating rubber quality.? TkSRPP3, TkSRPP4, and TkSRPP5 are associated with Tk root rubber particles. ? TkSRPP3 expression and Tk root rubber accumulation correspond. ? Decreasing TkSRPP3 gene expression results in decreased rubber content and quality. ? TkSRPP3 may help determine the amount and quality of rubber produced in Tk roots.
Publication year: 2012 Source:Phytochemistry, Volume 78 Xinkai Xie, James Kirby, Jay D. Keasling Genome sequence analysis of Ricinus communis has indicated the presence of at least 22 putative terpene synthase (TPS) genes, 13 of which appear to encode sesquiterpene synthases (SeTPSs); however, no SeTPS genes have been isolated from this plant to date. cDNAs were recovered for six SeTPS candidates, and these were subjected to characterization in vivo and in vitro. The RcSeTPS candidates were expressed in either Escherichia coli or Saccharomyces cerevisiae strains with engineered sesquiterpene biosynthetic pathways, but only two (RcSeTPS1 and RcSeTPS7) produced detectable levels of product. In order to check whether the engineered microbial hosts were adequately engineered for sesquiterpene production, a selection of SeTPS genes was chosen from other plant species and demonstrated consistently high sesquiterpene titers. Activity could be demonstrated in vitro for two of the RcSeTPS candidates (RcSeTPS5 and RcSeTPS10) that were not observed to be functional in our microbial hosts. RcSeTPS1 produced two products, (?)-?-copaene and (+)-?-cadinene, while RcSeTPS7 produced a single product, (E, E)-?-farnesene. Both RcSeTPS5 and RcSeTPS10 produced multiple sesquiterpenes.
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Four sesquiterpene synthases (SeTPSs) from Ricinus communis were characterized and represent the first examples of SeTPSs from the Euphorbiaceae. Challenges faced in the isolation and functional expression of cDNAs for all putative SeTPSs in the R. communis genome are described.? Analysis of Ricinus communis establishes up to 13 putative sesquiterpene synthases (SeTPSs). ? Only four of the recovered cDNAs were found to produce sesquiterpene products. ? Production levels in engineered microbial hosts were low compared to other plant SeTPSs. ? Verified products include (?)-?-copaene, (+)-?-cadinene, and (E, E)-?-farnesene.
Publication year: 2012 Source:Phytochemistry, Volume 78 Virginia Lanzotti, Elisa Barile, Vincenzo Antignani, Giuliano Bonanomi, Felice Scala A bioassay-guided phytochemical analysis of the polar extract from the bulbs of garlic, Allium sativum L., var. Voghiera, typical of Voghiera, Ferrara (Italy), allowed the isolation of ten furostanol saponins; voghieroside A1/A2 and voghieroside B1/B2, based on the rare agapanthagenin aglycone; voghieroside C1/C2, based on agigenin aglycone; and voghieroside D1/D2 and E1/E2, based on gitogenin aglycone. In addition, we found two known spirostanol saponins, agigenin 3-O-trisaccharide and gitogenin 3-O-tetrasaccharide. The chemical structures of the isolated compounds were established through a combination of extensive nuclear magnetic resonance, mass spectrometry and chemical analyses. High concentrations of two eugenol diglycosides were also found for the first time in Allium spp. The isolated compounds were evaluated for their antimicrobial activity towards two fungal species, the air-borne pathogen Botrytis cinerea and the antagonistic fungus Trichoderma harzianum.
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Ten furostanol saponins, voghierosides A1/A2-E1/E2, were isolated from Voghiera garlic, together with known spirostanol saponins and eugenol diglycosides, and their stereostructures elucidated by spectroscopic and chemical methods. The isolated compounds showed a significant antimicrobial activity against Botrytis and Trichoderma.? Ten furostanol saponins were isolated from Voghiera garlic. ? Eugenol diglycosides were reported in garlic for the first time. ? Antimicrobial activity of voghierosides were detected against Botrytis and Trichoderma. ? The activity increased with saponin concentration. ? The activity is inversely proportional to number of sugars.
Publication year: 2012 Source:Phytochemistry Masahiko Isaka, Urarat Srisanoh, Malipan Sappan, Sumalee Supothina, Thitiya Boonpratuang Sterostreins F–O (1–10), 10 illudalanes and norilludalanes, were isolated from cultures of the Basidiomycete Stereum ostrea BCC 22955. Their structures were elucidated by analyses of the NMR spectroscopic and mass spectrometry data. Sterostreins M (8), N (9), and O (10) are pyridine-containing illudalanes.
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Sterostreins F–O (1–10), 10 illudalanes and norilludalanes were isolated from cultures of the Basidiomycete Stereum ostrea BCC 22955.? Ten illudalane and norilludalane triterpenoids were isolated from cultures of Stereum ostrea BCC 22955. ? Their structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. ? Sterostreins M, N, and O are pyridine-containing illudalanes.
Publication year: 2012 Source:Phytochemistry, Volume 78 Tomáš ?ezanka, Jaromír Lukavský, Lucie Siristova, Karel Sigler Reversed phase liquid chromatography–atmospheric pressure chemical ionization mass spectrometry (RP-HPLC/APCI-MS) was used for direct analysis of triacylglycerols (TAGs) from different strains of the cyanobacteria Mastigocladus laminosus, Tolypothrix cf. tenuis and Tolypothrix distorta. This technique enabled us to identify and quantify the specific molecular species of TAGs directly from lipid extracts of the cyanobacteria. The regioisomeric series of TAGs having ?-linolenic and ?-linolenic and also oleic and cis-vaccenic acids were separated by RP-HPLC and identified by APCI-MS. M. laminosus produced only a few molecular species of TAGs, including both isomers of octadecenoic (oleic and vaccenic) acid, while T. distorta contained tens of molecular species of TAGs having FAs with up to four double bonds (stearidonic acid and including also its positional isomer, i.e. 3,6,9,12-octadecatetraenoic acid) and both positional isomers (? and ?) of linolenic acids. Individual strains of both cyanobacteria exhibited different contents of polyunsaturated fatty acids (Tolypothrix sp.) and different distribution of positional isomers of monoenoic fatty acids in TAGs (M. laminosus).
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The triacylglycerols (TAGs) of cyanobacteria, i.e. Mastigocladus laminosus, Tolypothrix sp. were analyzed by RP-HPLC/APCI-MS. Both the proportion of polyunsaturated TAGs in Tolypothrix and the proportion of positional isomers in Mastigocladus differed significantly depending on locality.? Over 70 triacylglycerols having at least one PUFA were found in two Tolypothrix cyanobacteria. ? The Tolypothrix strains from different localities produce different TAGs. ? Proportion of positional isomers of Mastigocladus TAGs from different localities also differs.
Publication year: 2012 Source:Phytochemistry, Volume 78 Lenka Franková, Stephen C. Fry Angiosperms possess a retaining trans-?-xylosidase activity that catalyses the inter-molecular transfer of xylose residues between xyloglucan structures. To identify the linkage of the newly transferred ?-xylose residue, we used [Xyl-3H]XXXG (xyloglucan heptasaccharide) as donor substrate and reductively-aminated xyloglucan oligosaccharides (XGO–NH2) as acceptor. Asparagus officinalis enzyme extracts generated cationic radioactive products ([3H]Xyl·XGO–NH2) that were Driselase-digestible to a neutral trisaccharide containing an ?-[3H]xylose residue. After borohydride reduction, the trimer exhibited high molybdate-affinity, indicating xylobiosyl-(1?6)-glucitol rather than a di-xylosylated glucitol. Thus the trans-?-xylosidase had grafted an additional ?-[3H]xylose residue onto the xylose of an isoprimeverose unit. The trisaccharide was rapidly acetolysed to an ?-[3H]xylobiose, confirming the presence of an acetolysis-labile (1?6)-bond. The ?-[3H]xylobiitol formed by reduction of this ?-[3H]xylobiose had low molybdate-affinity, indicating a (1?2) or (1?4) linkage. In NaOH, the ?-[3H]xylobiose underwent alkaline peeling at the moderate rate characteristic of a (1?4)-disaccharide. Finally, we synthesised eight non-radioactive xylobioses [? and ?; (1?1), (1?2), (1?3) and (1?4)] and found that the [3H]xylobiose co-chromatographed only with (1?4)-?-xylobiose. We conclude that Asparagus trans-?-xylosidase activity generates a novel xyloglucan building block, ?-d-Xylp-(1?4)-?-d-Xylp-(1?6)-d-Glc (abbreviation: ‘V’). Modifying xyloglucan structures in this way may alter oligosaccharin activities, or change their suitability as acceptor substrates for xyloglucan endotransglucosylase (XET) activity.
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Asparagus trans-?-xylosidase activity catalysed the transfer of ?-xylose residues between xyloglucan oligosaccharides, generating a novel repeat-unit, characterised radiochemically as ?-d-Xylp-(1?4)-?-d-Xylp- (1?6)-d-Glc, abbreviation ‘V’. Eight authentic xylopyranose disaccharides were also synthesised for use as markers.? Plant enzyme catalyses [3H]xylosyl transfer between xyloglucan oligosaccharides. ? Novel repeat-unit (‘V’) thus formed is identified as ?-Xyl-(1,4)-?-Xyl-(1,6)-Glc. ? Highly sensitive methods developed for radiochemically characterising V. ? Eight xylose disaccharides, some not previously available, synthesised as markers. ? V units may affect oligosaccharin activity or xyloglucan’s suitability as XET substrate.
Publication year: 2012 Source:Phytochemistry, Volume 78 Dara Dastan, Peyman Salehi, Ahmad Reza Gohari, Stefanie Zimmermann, Marcel Kaiser, Matthias Hamburger, Hamid Reza Khavasi, Samad Nejad Ebrahimi The first disesquiterpene coumarin, sanandajin, five sesquiterpene coumarins, kamolonol acetate, fekrynol acetate, ethyl galbanate, methyl galbanate, farnesiferol B, and a sesquiterpene, aristolone, were isolated from a n-hexane extract of Ferula pseudalliacea roots. The structures were elucidated by 1D and 2D NMR, HR-ESIMS data, and kamolonol acetate was confirmed by single-crystal X-ray analysis. The absolute configuration of compounds was established by comparison of experimental and simulated ECD spectra using time dependence density function theory (TDDFT). In vitro antiplasmodial activity against Plasmodium falciparum K1 strain was determined. sanandajin, kamolonol acetate and methyl galbanate showed moderate antiplasmodial activity, with IC50 values of 2.6, 16.1 and 7.1?M, respectively.
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The first disesquiterpene coumarin, a sesquiterpene coumarin, and four known sesquiterpene coumarins were isolated from the roots of Ferula pseudalliacea. The absolute configurations of four of the compounds were established by comparison of experimental and simulated ECD spectra using time dependence density function theory (TDDFT).? Disesquiterpene coumarin and sesquiterpene coumarins were identified in the root extract of Ferula pseudalliacea. ? ECD spectra were used to assign the absolute configurations of compounds. ? Three compounds showed moderate antiplasmodial activity.
Publication year: 2012 Source:Phytochemistry, Volume 77 Milena ?avi?, Milica Grozdanovi?, Aleksandar Baji?, Tatjana Srdi?-Raji?, Pavle R. An?jus, Marija Gavrovi?-Jankulovi? Actinidin belongs to the papain-like family of cysteine proteases and is a major kiwifruit allergen. In this study, the effect of actinidin on cellular morphology and adhesion of T84 intestinal cells was investigated. Both rounding and detachment of T84 cells were observed upon actinidin treatment. The morphological changes and cell desquamation was protease-dependent, as well as time- and concentration-dependent. Changes of intercellular adhesion and adhesion of epithelial cells to collagen upon actinidin treatment could be responsible for the cell rounding and give rise to discontinuous breaches in the epithelial monolayer observed in this study. Actinidin’s action on cell morphology, adhesion and monolayer integrity were not due to compromised viability of T84 epithelial cells, as confirmed by MTT assay and flow cytometric analysis of the cell cycle. Damage to the epithelial monolayer of the intestine induced by actinidin should be further evaluated as an important factor in the development of kiwifruit allergy and other intestinal disorders.
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Kiwifruit allergen actinidin induces protease-dependent morphology changes of T84 intestinal cells, leading to cell rounding and desquamation of the epithelial monolayer, without affecting cell viability.? Actinidin is a cysteine protease from kiwifruit with allergenic properties. ? We investigated if actinidin induces changes in morphology and adhesion of T84 cells. ? Actinidin led to cell rounding and desquamation of the T84 epithelial monolayer. ? The observed effects were protease-, time- and concentration-dependant. ? Viability of T84 epithelial cells was not compromised upon actinidin treatment.
Publication year: 2012 Source:Phytochemistry, Volume 78 Yi-xin Ou, Yao-yao Li, Xiao-ming Qian, Yue-mao Shen Thirteen diterpenoids, named radianspenes A–M (1–13), including three lactams radianspenes J (10), K (11) and L (12) and one dimer radianspene M (13), were isolated from fermentation products of the higher fungal strain Coprinus radians M65. All these compounds possessing guanacastane skeleton were evaluated for antitumor activity using MDA-MB-435 cell line. Radianspene C exhibited inhibitory activity with IC50 of 0.91?M.
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Thirteen diterpenoids, named radianspenes A–M (1–13), including three lactams, radianspenes J (10), K (11) and L (12) and one dimer radianspene M (13), were isolated from Coprinus radians M65.? Radianspenes A–M with guanacastane skeleton were isolated from Coprinus radians M65. ? Radianspene M represents a dimeric diterpenoid besides ent-kaurane dimer. ? The structure of radianspene M was confirmed by X-ray diffraction analysis. ? Radianspene C shows cytotoxicity to MDA-MB-435 with IC50 of 0.91?M.
Publication year: 2012 Source:Phytochemistry, Volume 78 Dimitre A. Ivanov, Mark A. Bernards American ginseng (Panax quinquefolius L.) produces triterpenoid saponins, ginsenosides, that possess mild fungitoxic activity toward some common ginseng leaf pathogens. However, numerous oomycete root pathogens of ginseng, most notably Pythium irregulare Buisman, are able to partially deglycosylate 20 (S)-protopanaxadiol ginsenosides Rb1, Rd and gypenoside XVII via extracellular glycosidases, leading to a common product, ginsenoside F2. Conversion of the common 20 (S)-protopanaxadiols into F2 requires both ? (1?6) and ? (1?2) glucosidase activity. In the present study, the ability of nine distinct isolates of P. irregulare, as well as a P. ultimum Trow isolate and two isolates of Trichoderma hamatum (Bonord.) Bainier, to deglycosylate 20 (S)-protopanaxadiols, in vitro was examined. The pathogenicity of each isolate was also examined by scoring the severity of disease symptoms caused by each in separate inoculations of one- and two-year old ginseng seedlings. Disease severity was scored using a disease severity index, as well as by taking Fv/Fm measurements of leaves during a 14-day infection period. Based on these measurements, it was concluded that (1) the use of direct Fv/Fm measurements correlates strongly with observations of disease severity (R2=0.79), and that (2) the pathogenicity of P. irregulare isolates correlates with their ability to deglycosylate ginsenosides (R2=0.57). These results further support the hypothesis that the pathogenicity of P. irregulare on ginseng roots is dependent, in part, on the ability of this organism to deglycosylate ginsenosides.
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The ability of Pythium irregulare strains to infect ginseng roots correlates with their metabolic capacity to deglycosylate ginsenosides via extracellular ginsenosidases.? Pythium irregulare produces extracellular enzymes that deglycosylate ginsenosides. ? The ability of P. irregulare isolates to deglycosylate ginsenosides varies. ? The extent of ginsenoside deglycosylation correlates with disease severity.
Publication year: 2012 Source:Phytochemistry Ibrahim Jantan, Fadlina Chany Saputri Three benzophenones, 2,6,3?,5?-tetrahydroxybenzophenone (1), 3,4,5,3?,5?-pentahydroxybenzophenone (3) and 3,5,3?,5?-tetrahydroxy-4-methoxybenzophenone (4), as well as a xanthone, 1,3,6-trihydroxy-5-methoxy-7-(3?-methyl-2?-oxo-but-3?-enyl)xanthone (9), were isolated from the twigs of Garcinia cantleyana var. cantleyana. Eight known compounds, 3,4,5,3?-tetrahydroxy benzophenone (2), 1,3,5-trihydroxyxanthone (5), 1,3,8-trihydroxyxanthone (6), 2,4,7-trihydroxyxanthone (7), 1,3,5,7-tetrahydroxyxanthone (8), quercetin, glutin-5-en-3?-ol and friedelin were also isolated. The structures of the compounds were elucidated by spectroscopic methods. The compounds were investigated for their ability to inhibit low-density lipoprotein (LDL) oxidation and platelet aggregation in human whole blood in vitro. Most of the compounds showed strong antioxidant activity with compound 8 showing the highest inhibition with an IC50 value of 0.5?M, comparable to that of probucol. Among the compounds tested, only compound 4 exhibited strong inhibitory activity against platelet aggregation induced by arachidonic acid (AA), adenosine diphosphate (ADP) and collagen. Compounds 3, 5 and 8 showed selective inhibitory activity on platelet aggregation induced by ADP.
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Four benzophenones (1–4) and five xanthones (5–9) isolated from the twigs of Garcinia cantleyana var. cantleyana showed high LDL antioxidant and antiplatelet activities with 8 exhibiting the strongest inhibition on LDL oxidation with IC50 value comparable to that of probucol.? Three benzophenones were isolated from Garcinia cantleyana var. cantleyana. ? A xanthone, with a rare, 2-oxoprenyl group, was also isolated. ? Compound 8 showed the highest LDL antioxidant activity, comparable to probucol. ? Compound 4 exhibited the strongest inhibition on AA-induced platelet aggregation.
Publication year: 2012 Source:Phytochemistry, Volume 78 Kazuya Koyama, Hiroko Ikeda, Puspa Raj Poudel, Nami Goto-Yamamoto Biosynthesis of phenolic compounds is known to be sensitive to light environments, which reflects the possible role of these compounds for photoprotection in plants. Herein, the effects of UV and visible light on biosynthesis of flavonoids was investigated, i.e., proanthocyanidins (PAs) and flavonols, in young berry skins of a red-wine grape, Vitis vinifera cv. Cabernet Sauvignon. Shading with light-proof boxes from the flowering stage until 49days after treatment (DAT) partially decreased PA concentrations, and completely decreased flavonol concentrations in the berry skins. Shading decreased the transcript abundance of a flavonol-related gene more remarkably than those of PA-related genes. In addition, light exclusion influenced the composition of PAs, such as the decrease in the proportion of trihydroxylated subunits and the mean degree of polymerization (mDP) within PAs. However, solar UV exclusion did not affect the concentration and composition of PAs, whereas this exclusion remarkably decreased the flavonol concentration. Consistently, UV exclusion did not influence the transcript levels of PA-related genes, whereas it dramatically decreased that of flavonol-related genes. These findings indicated a different light regulation of the biosynthesis of these flavonoids in young berry skins of wine grape. Visible light primarily induces biosynthesis of PAs and affects their composition, whereas UV light specifically induces biosynthesis of flavonols. Distinct roles of members of a MYB transcription factor family for light regulation of flavonoid biosynthesis were proposed.
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Visible light primarily induces biosynthesis of proanthocyanidins and increases the level of B-ring hydroxylation in proanthocyanidin subunits, whereas UV light specifically induces biosynthesis of flavonol in young berry skins of wine grape.? Visible light induces biosynthesis of proanthocyanidins in young grape skins. ? Visible light increases the level of B-ring hydroxylation of proanthocyanidins. ? UV light specifically induces biosynthesis of flavonol. ? The decrease in proanthocyanidin biosynthesis by light exclusion is limited. ? Members of a MYB transcription factor family are regulated differently by light.
Publication year: 2012 Source:Phytochemistry Chun-Tang Chiou, Yao-Haur Kuo, Yu-Yi Chan, Shin-Hun Juang, Hsiu-Hui Chan, Tian-Shung Wu Ajuga taiwanensis is widely used for the treatment of hepatitis and hepatoma in Taiwanese folk medicine. However, its bioactive components and mechanism of action are unclear. Herein, ajugalide-B (ATMA), a neoclerodane diterpenoid isolated from Ajuga taiwanensis, is reported to exhibit high anti-proliferative activity against tumor cell lines from various tissues. These results demonstrate that ATMA disrupts the focal adhesion complex by decreasing phosphorylation of paxillin and focal adhesion kinase (FAK). As a result, anoikis, a specific type of apoptosis caused by detachment of cells, is triggered by activation of caspase-8 in A549 cells. Furthermore, ATMA also blocks anchorage-independent growth and cell migration and, therefore, ATMA may serve as a lead compound for the developing of anti-cancer therapeuties with anoikis-inducing properties.
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Ajugalide-B (ATMA), a neoclerodane diterpenoid isolated from Ajuga taiwanensis, presented potent anticancer activity against tumor cell lines from various tissues by disrupting the focal adhesion complex and consequently triggering anoikis.? ATMA is a neoclerodane diterpenoid isolated from Ajuga taiwanensis. ? ATMA disrupts the focal adhesion complex by decreasing phosphorylation of paxillin and focal adhesion kinase (FAK). ? ATMA reduces the tumorigenic and metastatic abilities of A549 cancer cells.
Publication year: 2012 Source:Phytochemistry Yu-Chieh Chien, Chu-Hung Lin, Michael Y. Chiang, Hsun-Shuo Chang, Chang-Hui Liao, Ih-Sheng Chen, Chien-Fang Peng, Ian-Lih Tsai Bioassay-guided fractionation of the methanolic extract of the root of Ehretia longiflora (Boraginaceae) afforded eight compounds, ehretiquinone (1), ehretiolide (2), ehreticoumarin (3), ehretilactone A (4), ehretilactone B (5), ehretiamide (6), ehretine (7), and ehretiate (8), together with 12 known compounds (9–20). The relative configuration of 1 was determined by single crystal X-ray diffraction. Among the isolates, 1 and prenylhydroquinone (14) showed antitubercular activity against Mycobacterium tuberculosis strain H37Rv with MIC values of 25.0 and 26.2?g/mL, respectively. Moreover, 1 exhibited inhibitory effects on N-formylmethionylleucylphenylalanine (fMLP)-induced superoxide production, with IC50 value of 0.36±0.03?M.
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Compounds 1–8, together with 12 known compounds were isolated from the root tissue of Ehretia longiflora. Compound 1 exhibited inhibitory activity against fMLP-induced superoxide production by human neutrophils with in vitro IC50 values of 0.36?M and showed antitubercular activity against Mycobacterium tuberculosis strain H37Rv with MIC values of 25.0?g/mL.? Eight compounds and 12 known compounds were isolated from the root of Ehretia longiflora. ? The relative configuration of ehretiquinone was deduced by X-ray analysis. ? Ehretiquinone and prenylhydroquinone showed antitubercular activity. ? Ehretiquinone exhibited anti-inflammatory activity.
Publication year: 2012 Source:Phytochemistry Nabil Ali Al-Mekhlafi, Khozirah Shaari, Faridah Abas, Ralf Kneer, Ethel Jeyaseela Jeyaraj, Johnson Stanslas, Naoshi Yamamoto, Toshio Honda, Nordin H. Lajis Phytochemical investigation on the leaves of Labisia pumila (Myrsinaceae), an important medicinal herb in Malaysia, has led to the isolation of 1-O-methyl-6-acetoxy-5-(pentadec-10Z-enyl)resorcinol (1), labisiaquinone A (2) and labisiaquinone B (3). Along with these, 16 known compounds including 1-O-methyl-6-acetoxy-5-pentadecylresorcinol (4), 5-(pentadec-10Z-enyl)resorcinol (5), 5-(pentadecyl)resorcinol (6), (?)-loliolide (7), stigmasterol (8), 4-hydroxyphenylethylamine (9), 3,4,5-trihydroxybenzoic acid (10), 3,4-dihydroxybenzoic acid (11), (+)-catechin (12), (?)-epicatechin (13), kaempferol-3-O-?-rhamnopyranosyl-7-O-?-glycopyranoside (14), kaempferol-4?-O-?-glycopyranoside (15), quercetin-3-O-?-rhamnopyranoside (16), kaempferol-3-O-?-rhamnopyranoside (17), (9Z,12Z)-octadeca-9,12-dienoic acid (18) and stigmasterol-3-O-?-glycopyranoside (19) were also isolated. The structures of these compounds were established on the basis of 1D and 2D NMR spectroscopy techniques (1H, 13C, COSY, HSQC, NOESY and HMBC experiments), mass spectrometry and chemical derivatization. Among the constituents tested 1 and 4 exhibited strongest cytotoxic activity against the PC3, HCT116 and MCF-7 cell lines (IC50 values ?10?M), and they showed selectivity towards the first two-cell lines relative to the last one.
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1-O-methyl-6-acetoxy-5-(pentadec-10Z-enyl)resorcinol (1), labisiaquinone A (2) and labisiaquinone B (3), together with 16 known compounds, were isolated from the leaves of Labisia pumila (Myrsinaceae). Their structures were determined by spectroscopic methods.? Nineteen compounds (1–19) were isolated from Labisia pumila. ? The first comprehensive phytochemical study on this medicinal plant. ? Structures were determined based on spectrometry and chemical reaction. ? Compounds 1 and 4 were found to exhibit strong cytotoxic activity.
Publication year: 2012 Source:Phytochemistry, Volume 78 Xuesong Zhao, Juan Gao, Chengcheng Song, Qiang Fang, Nan Wang, Tianjiao Zhao, Dongbo Liu, Yifa Zhou A ginseng pathogen, Cylindrocarpon destructans, and five nonpathogens were tested for their sensitivity to a total ginsenoside fraction (T-GF), a protopanaxadiol-type ginsenoside fraction (PPD-GF) and a protopanaxatriol-type ginsenoside fraction (PPT-GF) from the roots of Panax ginseng C.A. Meyer. The results showed that T-GF inhibited growth of the five ginseng nonpathogens, while it promoted growth of the ginseng pathogen C. destructans. PPT-GF and PPD-GF both inhibited the growth of the five ginseng nonpathogens, although the activity of PPT-GF was higher than that of PPD-GF. PPT-GF and PPD-GF exhibited different activities on C. destructans: PPT-GF inhibited its growth, whereas PPD-GF significantly enhanced its growth. The subsequent analysis of enzymatic degradation of ginsenosides by the test fungi showed that C. destructans can consecutively hydrolyze the terminal monosaccharide units from the sugar chains attached at C3 and C20 in PPD-type ginsenosides by extracellular glycosidase activity to yield four major products, gypenoside XVII (G-XVII), compound O, compound Mb and the ginsenoside F2. By contrast, the ginseng nonpathogens Aspergillus nidulans and Cladosporium fulvum have no extracellular glycosidase activity toward sugar chains attached to C3 in PPD-type ginsenosides. These results indicated that ginsenosides might act as host chemical defenses, while the ginseng root pathogenic fungi might counter their toxicity by converting PPD-type ginsenosides into growth or host recognition factors. The ability of ginseng root pathogens to deglycosylate PPD-type ginsenosides may be a pathogenicity factor.
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PPT-type ginsenosides from Chinese ginseng inhibited growth of all six test fungi. PPD-type ginsenosides promoted growth of the ginseng pathogen Cylindrocarpon destructans, while inhibiting that of nonpathogens. C. destructans can consecutively hydrolyze sugar chains attached at C3 and C20 in PPD-type ginsenosides by an extracellular glycosidase.? PPT-type ginsenosides from Chinese ginseng inhibited growth of all six test fungi. ? PPD-type ginsenosides promoted growth of the ginseng pathogen Cylindrocarpon destructans. ? C. destructans can enzymatically degrade PPD-type ginsenosides.
Publication year: 2012 Source:Phytochemistry Nobuhiro Hirai, Kumiko Iwami, Mari Horiuchi, Kenji Kano, Yasushi Todoroki, Hajime Ohigashi Abscisic acid (ABA, 1), a plant hormone, has electrophilicity derived almost entirely from the side chain, 3-methylpenta-2,4-dienoic acid. The electrochemical property of ABA was investigated by analysis of its cathodic reaction. ABA methyl ester (1-Me) was reduced at a peak potential of ?1.6V to give a unique and unstable bicyclic compound (5-Me) as a major product at pH 3 and 7. This finding showed that an electron was absorbed in the conjugated dienecarboxyl group, and that C-5 with a high electron density attacked C-2? through an intramolecular nucleophilic addition. At pH 10, in addition to 5-Me, a compound 4-Me was formed by isomerization of 5-Me under alkaline conditions. For a cathodic reaction of ABA at pH 3 and 7, compound 5 was a major product as well as in the case of ABA methyl ester. However, at pH 10, a dimer (6) with an epoxy group, 1?-deoxy-ABA (7) and other compounds were formed instead of compounds 4 and 5. Compounds 4 and 5 were biologically inactive, suggesting the importance of the electrophilic side-chain of ABA for biological activity.
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ABA methyl ester (1-Me) was reduced at a cathode to give compound 5-Me which isomerized to compound 4-Me under an alkaline condition.? Electrophilicity of abscisic acid methyl ester was examined with electrolysis. ? Abscisic acid methyl ester was reduced at a cathode to give a unique product with a cyclopropyl ring. ? The product was isomerized to a stable compound under an alkaline condition.
Publication year: 2012 Source:Phytochemistry Jennifer E. Edwards, Paula N. Brown, Nadia Talent, Timothy A. Dickinson, Paul R. Shipley Since the 1800s, natural health products that contain hawthorn (Crataegus spp.) have been used in North America for the treatment of heart problems such as hypertension, angina, arrhythmia, and congestive heart failure. Traditionally, Native American tribes used hawthorn (Crataegus spp.) to treat gastrointestinal ailments and heart problems, and consumed the fruit as food. Hawthorn also has a long history of use in Europe and China for food, and in traditional medicine. Investigations of Crataegus spp. typically focus on the identification and quantification of flavonoids and anthocyanins, which have been shown to have pharmacological activity. The main flavonoids found in Crataegus spp. are hyperoside, vitexin, and additional glycosylated derivatives of these compounds. Reviewed herein are the botany, ethnobotany, and traditional use of hawthorn while focusing on the phytochemicals that have been reported in Crataegus species, and the variation in the described chemistry between individual species.
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The chemistry, botany, ethnobotany, and traditional use of hawthorn are reviewed with special emphasis on the variation in phytochemistry reported for different Crataegus species.? The chemistry of approximately 30 Crataegus species has been reported. ? The literature up to early 2011 is reviewed. ? The biological diversity of the genus Crataegus is outlined. ? The traditional use and ethnobotany of the genus Crataegus are briefly described. ? A high degree of phytochemical diversity was exhibited in the flavonoid profiles.
Publication year: 2012 Source:Phytochemistry Grisel Ponciano, Colleen M. McMahan, Wenshuang Xie, Gerard R. Lazo, Terry A. Coffelt, Jillian Collins-Silva, Aise Nural-Taban, Martin Gollery, David K. Shintani, Maureen C. Whalen Natural rubber biosynthesis in guayule (Parthenium argentatum Gray) is associated with moderately cold night temperatures. To begin to dissect the molecular events triggered by cold temperatures that govern rubber synthesis induction in guayule, the transcriptome of bark tissue, where rubber is produced, was investigated. A total of 11,748 quality expressed sequence tags (ESTs) were obtained. The vast majority of ESTs encoded proteins that are similar to stress-related proteins, whereas those encoding rubber biosynthesis-related proteins comprised just over one percent of the ESTs. Sequence information derived from the ESTs was used to design primers for quantitative analysis of the expression of genes that encode selected enzymes and proteins with potential impact on rubber biosynthesis in field-grown guayule plants, including 3-hydroxy-3-methylglutaryl-CoA synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, farnesyl pyrophosphate synthase, squalene synthase, small rubber particle protein, allene oxide synthase, and cis-prenyl transferase. Gene expression was studied for field-grown plants during the normal course of seasonal variation in temperature (monthly average maximum 41.7°C to minimum 0°C, from November 2005 through March 2007) and rubber transferase enzymatic activity was also evaluated. Levels of gene expression did not correlate with air temperatures nor with rubber transferase activity. Interestingly, a sudden increase in night temperature 10days before harvest took place in advance of the highest CPT gene expression level.
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Dissecting the molecular control of rubber biosynthesis: expression analysis of genes controlling pathway enzymes and rubber particle-associated proteins.? The first transcriptome of cold-acclimated guayule is described. ? All enzymes from both the MEV and MEP pathways were present. ? Isoprenoid pathway gene expression did not correlate with rubber synthesis rate. ? Gene expression levels for AOS and CPT were higher during the colder months.
Publication year: 2012 Source:Phytochemistry, Volume 78 Andre F. Cruz, Chantal Hamel, Chao Yang, Tomoko Matsubara, Yantai Gan, Asheesh K. Singh, Kousaku Kuwada, Takaaki Ishii Fusarium diseases cause major economic losses in wheat-based crop rotations. Volatile organic compounds (VOC) in wheat and rotation crops, such as chickpea, may negatively impact pathogenic Fusarium. Using the headspace GC–MS method, 16 VOC were found in greenhouse-grown wheat leaves: dimethylamine, 2-methyl-1-propanol, octanoic acid-ethyl ester, acetic acid, 2-ethyl-1-hexanol, nonanoic acid-ethyl ester, nonanol, N-ethyl-benzenamine, naphthalene, butylated hydroxytoluene, dimethoxy methane, phenol, 3-methyl-phenol, 3,4-dimethoxy-phenol, 2,4-bis (1,1-dimethyethyl)-phenol, and 1,4,7,10,13,16-hexaoxacyclooctadecane; and 10 VOC in field-grown chickpea leaves: ethanol, 1-penten-3-ol, 1-hexanol, cis-3-hexen-1-ol, trans-2-hexen-1-ol, trans-2-hexenal, 3-methyl-1-butanol, 3-hydroxy-2-butanone, 3-methyl-benzaldehyde and naphthalene. Also found was 1-penten-3-ol in chickpea roots and in the root nodules of two of the three cultivars tested. Chickpea VOC production pattern was related (P=0.023) to Ascochyta blight severity, suggesting that 1-penten-3-ol and cis-3-hexen-1-ol were induced by Ascochyta rabiei. Bioassays conducted in Petri plates established that chickpea-produced VOC used in isolation were generally more potent against Fusarium graminearum and Fusarium avenaceum than wheat-produced VOC, except for 2-ethyl-1-hexanol, which was rare in wheat and toxic to both Fusarium and tetraploid wheat. Whereas exposure to 1-penten-3-ol and 2-methyl-1-propanol could suppress radial growth by over 50% and octanoic acid-ethyl ester, nonanol, and nonanoic acid-ethyl ester had only weak effects, F. graminearum and F. avenaceum growth was completely inhibited by exposure to trans-2-hexenal, trans-2-hexen-1-ol, cis-3-hexen-1-ol, and 1-hexanol. Among these VOC, trans-2-hexenal and 1-hexanol protected wheat seedlings against F. avenaceum and F. graminearum, respectively, in a controlled condition experiment. Genetic variation in the production of 2-ethyl-1-hexanol, a potent VOC produced in low amount by wheat, suggests the possibility of selecting Fusarium resistance in wheat on the basis of leaf VOC concentration. Results also suggests that the level of Fusarium inoculum in chickpea–wheat rotation systems may be reduced by growing chickpea genotypes with high root and shoot levels of trans-2-hexen-1-ol and 1-hexanol.
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Certain volatile organic compounds (VOCs) from chickpea protect wheat in infested soil. Genetic selection of plants for VOC production could reduce disease in cropping systems.? Volatile organic compounds (VOCs) in wheat–chickpea rotation crops inhibit Fusarium. ? Wheat-produced VOCs are generally less potent than chickpea-produced VOCs. ? 2-Ethyl-1-hexanol is highly potent but scarcely produced in wheat. ? Variation in 2-ethyl-1-hexanol in 17 wheat type supports VOC-based genotype selection. ? VOCs induced in leaves are also induced in roots with potential rhizosphere impacts.
Publication year: 2012 Source:Phytochemistry Matthew O. Jones, Florence Piron-Prunier, Fabien Marcel, Elodie Piednoir-Barbeau, Abdullah A. Alsadon, Mahmoud A. Wahb-Allah, Abdullah A. Al-Doss, Chris Bowler, Peter M. Bramley, Paul D. Fraser, Abdelhafid Bendahmane Targeting Induced Local Lesions IN Genomes (TILLING) combines chemical mutagenesis with high throughput screening to allow the generation of alleles of selected genes. In this study, TILLING has been applied to produce a series of mutations in genes encoding essential components of the tomato light signal transduction pathway in an attempt to enhance fruit nutritional quality. Point mutations to DEETIOLATED1 (DET1), which is responsible for the high pigment2 (hp2) tomato mutant, resulted in elevated levels of both carotenoid and phenylpropanoid phytonutrients in ripe fruit, whilst immature fruit showed increased chlorophyll content, photosynthetic capacity and altered fruit morphology. Furthermore, genotypes with mutations to the UV-DAMAGED DNA BINDING PROTEIN 1 (DDB1), COP1 and COP1like were also characterised. These genotypes largely did not display phenotypes characteristic of mutation to light signalling components but their characterisation has enabled interrogation of structure function relationships of the mutated genes.
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A set of tomato alleles in the genes encoding light signal transduction pathway components DET1, COP10, COP1like and DDB1 produced by TILLING show increases in fruit phytonutrient content.? Targeting Induced Local Lesions in Genomes (TILLING) is a reverse-genetic strategy. ? Tomato signal transduction mutants were generated by TILLING. ? Mutations to DEETIOLATED1, DDB1, COP1 and COP1Like are described. ? Point mutations to DEETIOLATED1 enhance phytonutrient accumulation in fruit.
Publication year: 2012 Source:Phytochemistry Yong-Jiang Xu, Kenn Foubert, Liene Dhooghe, Filip Lemière, Sheila Maregesi, Christina M. Coleman, Yike Zou, Daneel Ferreira, Sandra Apers, Luc Pieters The combination of the hyphenated techniques LC–MS and LC–SPE–NMR constitutes a powerful platform for the rapid isolation and identification of minor components from natural sources. Electronic circular dichroism (ECD) is a useful tool to determine the absolute configuration of small quantities of chiral molecules. In order to search for minor constituents present in an Ormocarpum kirkii extract, these techniques were applied for the separation and structure elucidation of a series of isoflavanones, biflavanones and biscoumarins. After optimization of chromatographic conditions and subsequent isolation, MS and 1D and 2D NMR data were collected. Experimental and calculated ECD spectra were used in conjunction with NMR data to confirm the absolute configuration of these compounds. Eight compounds were identified for the first time and six have been previously reported. The present approach offers a strategy for accelerating research on natural products.
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The combination of the hyphenated techniques LC–MS and LC–SPE–NMR was applied for isolation and structure elucidation of minor constituents present in an Ormocarpum kirkii extract. Electronic circular dichroism experiments were used in conjunction with NMR data to determine the absolute configuration of isolated compounds, eight of which were reported for the first time, and six were known.? Structure elucidation of (bi)flavonoids from Ormocarpum kirkii by LC–MS, LC–SPE–NMR. ? Determination of absolute configuration by experimental and calculated ECD spectra. ? Eight compounds were identified for the first time, six were known.
Publication year: 2012 Source:Phytochemistry Shaza M. Al-Massarani, Samuel Bertrand, Andreas Nievergelt, Azza M. El-Shafae, Tawfeq A. Al-Howiriny, Nawal M. Al-Musayeib, Muriel Cuendet, Jean-Luc Wolfender Caralluma sinaica is sold on local markets of Saudi Arabia for various health benefits however no phytochemical study has specifically been performed on this species. NMR and UHPLC-ESI-TOF-MS profilings of the ethanolic extract of the whole plant reveal a very complex phytochemical composition dominated by pregnanes. Detailed information on its constituents was obtained after isolation. Six pregnane glycosides were obtained and characterized based on the extensive spectroscopic analysis (including IR, 1H NMR, 13C NMR and MS data), in addition to ten known compounds (seven pregnanes and three flavonoids). The compounds were identified as 12?-O-benzoyl-20-O-acetyl boucerin-3-O-6-deoxy-3-O-methyl-?-d-glucopyranosyl-(1?4)-?-d-cymaropyranosyl-(1?4)-?-d-cymaropyranoside, 12?-O-tigloyl-20-O-acetyl boucerin-3-O-?-d-glucopyranosyl-(1?4)-?-d-cymaropyranoside, 12?-O-benzoyl-20-O-acetyl boucerin-3-O-?-d-glucopyranosyl-(1?4)-?-d-digitalopyranosyl-(1?4)-?-d-cymaropyranosyl-(1?4)-?-d-cymaropyranoside, 12?-O-benzoyl-20-O-acetyl boucerin-3-O-?-d-glucopyranosyl-(1?4)-thevetopyranosyl-(1?4)-?-d-cymaropyranosyl-(1?4)-?-d-cymaropyranoside, 12?-O-benzoyl-20-O-tigloyl boucerin-3-O-?-d-glucopyranosyl-(1?4)-?-d-cymaropyranoside, 12?-20-O-dibenzoyl boucerin-3-O-?-d-glucopyranosyl-(1?4)-?-d-cymaropyranosyl-(1?4)-?-d-cymaropyranoside. Finally, the isolated compounds were evaluated for their quinone reductase induction.
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After profiling of the extract from Caralluma sinaica, 13 pregnane glycosides (six previously unreported) along with three flavonoids were identified and assessed for their quinone reductase induction.? NMR and UHPLC-TOF profiling of Caralluma sinaica reveal its complex pregnane composition. ? Six and seven known pregnanes were isolated from C. sinaica. ? A quinone reductase induction activity was shown for some pregnane glycosides. ? No relevant cytotoxicity was revealed for the C. sinaica extract.
Publication year: 2012 Source:Phytochemistry, Volume 78 Mahabaleshwar Hegde, Janser N. Oliveira, Joao G. da Costa, Elisa Loza-Reyes, Ervino Bleicher, Antonio E.G. Santana, John C. Caulfield, Patrick Mayon, Sarah Y. Dewhirst, Toby J.A. Bruce, John A. Pickett, Michael A. Birkett Upon insect herbivory, plants can release blends of volatile organic compounds (VOCs) that modify herbivore and natural enemy behaviour. We have shown recently that cotton, Gossypium hirsutum, emits a blend of defence VOCs that repels the cotton aphid, Aphis gossypii, upon herbivory by this notorious crop pest, including (Z)-3-hexenyl acetate, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), methyl salicylate and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT). In this study, we investigated changes in the defence VOC profile of G. hirsutum induced by the naturally-occurring plant elicitor cis-jasmone (CJ) and whether these changes modify the behaviour of A. gossypii. In four-arm olfactometer assays, VOCs from untreated plants were significantly attractive (P<0.05), whilst VOCs from CJ-treated plants were significantly repellent (P<0.05). The VOCs induced by CJ appeared to comprise (Z)-3-hexenyl acetate, DMNT, methyl salicylate and TMTT. In quantitative VOC collection studies, sustained release of DMNT and TMTT was observed in CJ-treated plants over a period of five days, with levels becoming statistically significantly higher than for control treated plants on the fifth day in most cases. Despite earlier indications, no statistically significant differences were observed in levels of (Z)-3-hexenyl acetate or methyl salicylate between CJ and control treatments on any day. Furthermore, DMNT and TMTT emissions from CJ-treated plants were further enhanced by subsequent addition of A. gossypii. CJ treatment induced statistically significantly higher DMNT and TMTT expression levels as early as day three, when A. gossypii was present. The results in this study show that CJ can induce the production of A. gossypii-induced VOCs from G. hirsutum, with potential for deployment in novel crop protection strategies.
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The ability of the naturally-occurring plant defence elicitor cis-jasmone (CJ) to activate defence in cotton, Gossypium hirsutum (Malvaceae), was investigated using the cotton aphid, Aphis gossypii. VOCs from untreated seedlings were significantly attractive, whilst VOCs from CJ-treated seedlings were significantly repellent. Significantly higher levels of (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene (TMTT) were emitted by CJ-treated seedlings. The results in this study show that CJ can induce the production of A. gossypii-induced VOCs from G. hirsutum, with potential for deployment in novel crop protection strategies..? cis-Jasmone (CJ) induces defence VOC release in cotton, Gossypium hirsutum. ? VOCs from CJ-treated cotton repel cotton aphids, Aphis gossypii. ? Emissions of DMNT and TMTT by cotton increase following CJ treatment. ? DMNT and TMTT emissions are enhanced by addition of A. gossypii.
Publication year: 2012 Source:Phytochemistry Hahk-Soo Kang, Bernard D. Santarsiero, Hyunjung Kim, Aleksej Krunic, Qi Shen, Steven M. Swanson, Heebyung Chai, A. Douglas Kinghorn, Jimmy Orjala The cell extract of a cultured terrestrial Nostoc sp. (UIC 10062), obtained from a sample collected at Grand Mere State Park in Michigan, displayed antiproliferative activity against the HT-29 human colon cancer cell line. Bioactivity-guided fractionation of the cell extract, combined with LC–MS analysis, led to the isolation of two cyclophanes, named merocyclophanes A and B (1 and 2). Their structures were determined by various spectroscopic techniques including HRESIMS, and 1D and 2D NMR analyses. The stereoconfiguration was assigned on the basis of X-ray crystallographic and CD analyses. The structures of merocyclophanes A and B (1 and 2) established a hitherto unknown [7.7]paracyclophane skeleton in nature, as characterized by ?-branched methyls at C-1/14. Merocyclophanes A and B (1 and 2) displayed antiproliferative activity against the HT-29 human colon cancer cell line with IC50 values of 3.3 and 1.7?M, respectively.
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Investigation of Nostoc sp. (UIC 10062) led to the isolation of paracyclophanes, merocyclophanes A and B, with activity in the HT-29 cancer cell line (IC50 3.3 and 1.7?M, respectively).? Two [7.7]paracyclophanes named merocyclophanes A and B were obtained. ? Both displayed antiproliferative activity against the HT-29 cancer cell line. ? Nostoc sp. (UIC 10062) was obtained from Grand Mere State Park in Michigan. ? Nostoc sp. was classified based on microscopic and 16S rRNA gene sequence analysis.
Publication year: 2012 Source:Phytochemistry, Volume 77 Jacob Pollier, Alain Goossens Oleanolic acid (3?-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with a widespread occurrence throughout the plant kingdom. In nature, the compound exists either as a free acid or as an aglycone precursor for triterpenoid saponins, in which it can be linked to one or more sugar chains. Oleanolic acid and its derivatives possess several promising pharmacological activities, such as hepatoprotective effects, and anti-inflammatory, antioxidant, or anticancer activities. With the recent elucidation of its biosynthesis and the imminent commercialization of the first oleanolic acid-derived drug, the compound promises to remain important for various studies. In this review, the recent progress in understanding the oleanolic acid biosynthesis and its pharmacology are discussed. Furthermore, the importance and potential application of synthetic oleanolic acid derivatives are highlighted, and research perspectives on oleanolic acid are given.
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Oleanolic acid (3?-hydroxyolean-12-en-28-oic acid) is a pentacyclic triterpenoid compound with various pharmacological activities and a widespread occurrence throughout the plant kingdom.? Oleanolic acid is a triterpenoid compound present in many plant species. ? The complete biosynthetic pathway leading to oleanolic acid is elucidated. ? Oleanolic acid exerts pharmacological activities such as hepatoprotective effects. ? Chemical derivatives of oleanolic acid have increased pharmacological activities. ? Perspectives on heterologous biosynthesis of oleanolic acid and its derivatives.
Publication year: 2012 Source:Phytochemistry, Volume 78 Tri R. Nuringtyas, Young H. Choi, Robert Verpoorte, Peter G.L. Klinkhamer, Kirsten A. Leiss Plants are attacked by many different herbivores. Some will consume whole leaves or roots, while others will attack specific types of tissue. Thus, insight into the metabolite profiles of different types of leaf tissues is necessary to understand plant resistance against herbivores. Jacobaea vulgaris, J. aquatica and three genotypes of their crossings were used to study the variation in metabolomic profiles between epidermis and mesophyll tissues. Extracts of epidermis and mesophyll tissues were obtained using carborundum abrasion (CA). Subsequently, 1H nuclear magnetic resonance (NMR) spectroscopy and multivariate data analyses were applied to compare the metabolome profiles. Orthogonal partial least-squares-discriminant analysis (OPLS-DA) resulted in a clear separation of epidermis and mesophyll extracts. The epidermis contained significantly higher amounts of jacaranone and phenylpropanoids, specifically chlorogenic (5-O-CQA) and feruloyl quinic (FQA) acids compared to the mesophyll. In contrast, the mesophyll showed significantly higher concentrations of pyrrolizidine alkaloids (PAs), specifically jacobine and jaconine. The tissue specific distribution of these compounds was constant over all genotypes tested. Phenylpropanoids, 5-O-CQA and FQA, as well as PAs are known for their inhibitory effect on herbivores, especially against thrips. Thrips feeding commences with the penetration of the epidermis, followed by ingestion of sub-epidermal or mesophyll. Thrips thus may have to encounter phenylpropanoids in the epidermis as the first line of defence, before encountering the PAs as the ultimate defence in the mesophyll. The finding of tissue specific defense may have a major impact on studies of plant resistance. We cannot judge resistance using analyses of a whole roots, leafs or flowers. In such a whole-organism approach, the levels of potential defense compounds are far below the real ones encountered in tissues involved in the first line of defense. Instead, it is of great importance to study the defence compounds in the specific tissue to which the herbivore is confined.
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Comparing epidermis and mesophyll metabolomes in the genus Jacobaea tissue specific distribution of defense compounds was observed. The epidermis contained more phenylpropanoids, while the mesophyll contained more pyrrolizidine alkaloids.? We compared the metabolomic profiles of epidermis and mesophyll in plants of the genus Jacobaea. ? The epidermis contained more phenylpropanoids, specifically chlorogenic acid. ? The mesophyll contained more pyrrolizidine alkaloids, specifically jacobine and jaconine. ? The observed distribution pattern was consistent over different genotypes. ? The result of tissue specific defense may have a major impact on host plant resistance.
Publication year: 2012 Source:Phytochemistry, Volume 77 Niels Agerbirk, Carl Erik Olsen By 2000, around 106 natural glucosinolates (GSLs) were probably documented. In the past decade, 26 additional natural GSL structures have been elucidated and documented. Hence, the total number of documented GSLs from nature by 2011 can be estimated to around 132. A considerable number of additional suggested structures are concluded not to be sufficiently documented. In many cases, NMR spectroscopy would have provided the missing structural information. Of the GSLs documented in the past decade, several are of previously unexpected structures and occur at considerable levels. Most originate from just four species: Barbarea vulgaris, Arabidopsis thaliana, Eruca sativa and Isatis tinctoria. Acyl derivatives of known GSLs comprised 15 of the 26 newly documented structures, while the remaining exhibited new substitution patterns or chain length, or contained a mercapto group or related thio-functionality.GSL identification methods are reviewed, and the importance of using authentic references and structure-sensitive detection methods such as MS and NMR is stressed, especially when species with relatively unknown chemistry are analyzed. An example of qualitative GSL analysis is presented with experimental details (group separation and HPLC of both intact and desulfated GSLs, detection and structure determination by UV, MS, NMR and susceptibility to myrosinase) with emphasis on the use of NMR for structure elucidation of even minor GSLs and GSL hydrolysis products. The example includes identification of a novel GSL, (R)-2-hydroxy-2-(3-hydroxyphenyl)ethylglucosinolate.Recent investigations of GSL evolution, based on investigations of species with well established phylogeny, are reviewed. From the relatively few such investigations, it is already clear that GSL profiles are regularly subject to evolution. This result is compatible with natural selection for specific GSL side chains. The probable existence of structure-specific GSL catabolism in intact plants suggests that biochemical evolution of GSLs has more complex implications than the mere liberation of a different hydrolysis product upon tissue disruption.
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We critically review documented glucosinolate structures, methods for qualitative glucosinolate analysis, glucosinolate evolution, and recent advances in glucosinolate biochemistry. Rather than being neutral markers of evolutionary origin, glucosinolates are bioactive specialized metabolites, and their evolution can be traced using phylogenetic trees.? We provide a critical review of reported natural glucosinolate structures. ? A considerable number of suggested structures are insufficiently documented. ? By 2011, around 132 natural glucosinolates were scientifically documented. ? Glucosinolates are specialized metabolites subject to frequent evolution. ? Side chain specific in planta metabolic reactions may influence glucosinolate evolution.
Publication year: 2012 Source:Phytochemistry, Volume 77 Natsajee Nualkaew, Hiroyuki Morita, Yoshihiko Shimokawa, Keishi Kinjo, Tetsuo Kushiro, Wanchai De-Eknamkul, Yutaka Ebizuka, Ikuro Abe The cDNA of a benzophenone synthase (BPS), a type III polyketide synthase (PKS), was cloned and the recombinant protein expressed from the fruit pericarps of Garcinia mangostana L., which contains mainly prenylated xanthones. The obtained GmBPS showed an amino acid sequence identity of 77–78% with other plant BPSs belonging to the same family (Clusiaceae). The recombinant enzyme produced 2,4,6-trihydroxybenzophenone as the predominant product with benzoyl CoA as substrate. It also accepted other substrates, such as other plant PKSs, and used 1–3molecules of malonyl CoA to form various phloroglucinol-type and polyketide lactone-type compounds. Thus, providing GmBPS with various substrates in vivo might redirect the xanthone biosynthetic pathway.
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The cDNA of a benzophenone synthase from Garcinia mangostana L. (GmBPS) was cloned, expressed, and mutated. The recombinant GmBPS was able to utilise various substrates and 1–3molecules of malonyl CoA to form a variety of phloroglucinol and polyketide-lactone products.? Benzophenone synthase (GmBPS) was cloned from Garcinia mangostana. ? GmBPS utilised various substrates and 1–3molecules of malonyl-CoA. ? The enzymatic products included phloroglucinol and polyketide-lactone compounds. ? The total volume of GmBPS active site is smaller than that of chalcone synthase. ? Site-directed mutation to accommodate larger aromatic substrates was performed.
Publication year: 2012 Source:Phytochemistry, Volume 77 Peter Bauer, Kristin Rudolph, Frieder Müller-Uri, Wolfgang Kreis Progesterone 5?-reductases (P5?R; EC 1.3.99.6) encoded by Vein Patterning 1 (VEP1) genes are capable of reducing the CC double-bond of a variety of enones enantioselectively. Sequence and activity data of orthologous P5?Rs were used to define a set of residues possibly responsible for the large differences in enzyme activity seen between rAtSt5?R and rDlP5?R, recombinant forms of P5?Rs from Arabidopsis thaliana and Digitalis lanata, respectively. Tyrosine-156, asparagine-205 and serine-248 were identified as hot spots in the rDlP5?R responsible for its low catalytic efficiency. These positions were individually substituted for amino acids found in the strong rAtSt5?R in the corresponding sites. Kinetic constants were determined for rDlP5?R and its mutants as well as for rAtSt5?R using progesterone and 2-cyclohexen-1-one as substrates. Enzyme mutants in which asparagine-205 was substituted for methionine or alanine showed considerably lower km and higher Kcat/km values than the wild-type DlP5?R, approaching the catalytic efficiency of strong P5?Rs. The introduced mutations not only lead to an improved capability to reduce progesterone but also to altered substrate preference. Our findings provided structural insights into the differences seen among the natural P5?Rs with regard to their substrate preferences and catalytic efficiencies.
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Vein Patterning 1-encoded progesterone 5?-reductases (P5?R) are substrate-promiscuous enone reductases. Amino acid residues responsible for P5?R ‘weakness’ were identified and the catalytic efficiency of P5?R of D. lanata was improved by site-directed mutagenesis.? Vein Patterning 1-encoded progesterone 5?-reductases are substrate-promiscuous enone reductases. ? Catalytically ‘strong’ and ‘weak’ progesterone 5?-reductases were identified. ? An activity-guided screen was used to propose ‘hot spots’ for site-directed mutagenesis. ? Catalytic efficiency of Vein Patterning 1-encoded progesterone 5?-reductase was improved. ? Amino acid residues responsible for progesterone 5?-reductase ‘weakness’ were substituted.
Publication year: 2012 Source:Phytochemistry, Volume 78 Loubna Ferchichi, Séverine Derbré, Khalid Mahmood, Kaatio Touré, David Guilet, Marc Litaudon, Khalijah Awang, A. Hamid A. Hadi, Anne Marie Le Ray, Pascal Richomme Advanced glycation end-products (AGEs) are associated with many pathogenic disorders such as Alzheimer’s disease, pathogenesis of diabetes, atherosclerosis or endothelial dysfunction leading to cardiovascular events. Clusiaceae and Calophyllaceae families are rich in compounds like polyphenols which are able to inhibit their formation and are therefore of great interest. Calophyllum flavoramulum Hend. & Wyatt-Sm., a native Malaysian plant, was selected after an anti-AGEs screening conducted on DCM and MeOH extracts from plants belonging to these aforementioned families. In a first study, bioguided fractionation of the MeOH leaf extract of C. flavoramulum afforded amentoflavone, 3-methoxy-2-hydroxyxanthone, 3,4-dihydroxy-tetrahydrofuran-3-carboxylic acid, quercitrin, 3,4-dihydroxybenzoic acid, canophyllol and apetalactone. Amentoflavone and 3-methoxy-2-hydroxyxanthone were found to be very potent (IC50=0.05 and 0.06mM respectively), while anti-AGEs activities of quercitrin and 3,4-dihydroxybenzoic acid appeared as moderately strong (IC50=0.5mM). In a second study, a systematic phytochemical study of the cyclohexane, DCM and EtOAc extracts obtained from the same plant was conducted to isolate the following products: flavoramulone, 6-deoxyjacareubin, rheediachromenoxanthone, 2,3-dihydroamentoflavone and benzoic acid. 3,4-Dihydroxy-tetrahydrofuran-3-carboxylic acid and flavoramulone were isolated for the first time and their structures were identified by means of IR, MS and NMR spectrometries.
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Isolation and identification of amentoflavone 1 and 3-methoxy-2-hydroxyxanthone 2 as very potent advanced glycation end-products (AGEs) inhibitors and of 3,4-dihydroxy-tetrahydrofuran-3-carboxylic acid 3 and flavoramulone 8 as a new product from Calophyllum flavo-ramulum MeOH leaf extract.? Extracts from Clusiaceae/Calophyllaceae were tested for their antiAGEs potential. ? Calophyllum flavoramulum MeOH leaf extract was selected. ? Its bioguided fractionation led to identify 1 and 2 as very potent AGEs inhibitors. ? Two new products 3 and 8 were also isolated and described.
Publication year: 2012 Source:Phytochemistry, Volume 77 Hirosuke Kanamoto, Miho Takemura, Kanji Ohyama Three genes homologous to plant lipoxygenase genes were identified from the EST libraries of Marchantia polymorpha, in order to clarify the function of LOXs in bryophytes. Full-length genes were isolated using 5?- and 3?-RACE methods and named MpLOX1, MpLOX2, and MpLOX3, respectively. To investigate the enzymatic activities of liverwort LOXs, recombinant MpLOX1, MpLOX2, and MpLOX3 proteins were prepared from Escherichia coli cells expressing the corresponding gene. LC–MS/MS analyses and chiral column chromatography of their reaction products showed that MpLOX1 codes for 11S/15S-lipoxygenase against eicosapentaenoic acid and for 15S-lipoxygenase against arachidonic acid, and that MpLOX2 and MpLOX3 code for 15S-lipoxygenase against eicosapentaenoic and arachidonic acids. Phylogenetic analysis showed that the liverwort lipoxygenase genes separated from the ancestor of higher plants in the early stages of plant evolution. Quantification analyses suggested that arachidonic acid and eicosapentaenoic acid were preferred substrates. Furthermore, each liverwort lipoxygenase exhibited highest activity at pH 7.0 and dependency on Ca2+ ion in the oxygenation reaction.
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Three lipoxygenase genes were identified from Marchantia polymorpha. They preferentially use eicosapentaenoic acid as a substrate to produce 15S-HPEPE or 11S-HPEPE.? Three genes homologous to plant lipoxygenase were identified from Marchantia polymorpha. ? MpLOX1 showed 11S- and 15S-LOX activities for EPA substrate and 15S-LOX activity for AA. ? MpLOX2 and MpLOX3 exhibited 15S-LOX activity for both EPA and AA.
Publication year: 2012 Source:Phytochemistry, Volume 77 Jens Rohloff, Joachim Kopka, Alexander Erban, Per Winge, Robert C. Wilson, Atle M. Bones, Jahn Davik, Stephen K. Randall, Muath K. Alsheikh Winter freezing damage is a crucial factor in overwintering crops such as the octoploid strawberry (Fragaria×ananassa Duch.) when grown in a perennial cultivation system. Our study aimed at assessing metabolic processes and regulatory mechanisms in the close-related diploid model woodland strawberry (Fragaria vescaL.) during a 10-days cold acclimation experiment. Based on gas chromatography/time-of-flight-mass spectrometry (GC/TOF-MS) metabolite profiling of three F. vesca genotypes, clear distinctions could be made between leaves and non-photosynthesizing roots, underscoring the evolvement of organ-dependent cold acclimation strategies. Carbohydrate and amino acid metabolism, photosynthetic acclimation, and antioxidant and detoxification systems (ascorbate pathway) were strongly affected. Metabolic changes in F. vesca included the strong modulation of central metabolism, and induction of osmotically-active sugars (fructose, glucose), amino acids (aspartic acid), and amines (putrescine). In contrast, a distinct impact on the amino acid proline, known to be cold-induced in other plant systems, was conspicuously absent. Levels of galactinol and raffinose, key metabolites of the cold-inducible raffinose pathway, were drastically enhanced in both leaves and roots throughout the cold acclimation period of 10days. Furthermore, initial freezing tests and multifaceted GC/TOF-MS data processing (Venn diagrams, independent component analysis, hierarchical clustering) showed that changes in metabolite pools of cold-acclimated F. vesca were clearly influenced by genotype.
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Metabolite profiling based on gas chromatography/time-of-flight-mass spectrometry (GC/TOF-MS) was applied to investigate changes in central metabolism in leaves and roots of Fragaria vesca L. (woodland strawberry) under cold acclimation.? Metabolite pools of Fragaria vesca were perturbated upon cold acclimation during a 10-days study. ? Mainly sugars, amino acids and amines were affected. ? Multivariate analyses revealed differences between leaves and roots, genotypes and time points. ? The raffinose pathway was strongly induced upon cold acclimation.
Publication year: 2012 Source:Phytochemistry, Volume 77 Mariana Gil, Mariela Pontin, Federico Berli, Rubén Bottini, Patricia Piccoli This study investigated the terpene profiles as determined by GC–EIMS analysis of in vitro cultured plants of Vitis vinifera exposed to a “field-like” dose of UV-B (4.75kJm?2d?1) administered at two different fluence rates (low, 16h at 8.25?Wcm?2, and high 4h at 33?Wcm?2). Low UV-B treatment increased levels of the membrane-related triterpenes sitosterol, stigmasterol and lupeol, more notable in young leaves, suggesting elicitation of a mechanism for grapevine acclimation. By contrast, accumulation of compounds with antioxidant properties, diterpenes ? and ? tocopherol and phytol, the sesquiterpene E-nerolidol and the monoterpenes carene, ?-pinene and terpinolene had maximum accumulation under high UV-B, which was accentuated in mature leaves. Also the levels of the sesquiterpenic stress-related hormone abscisic acid (ABA) increased under high UV-B, although 24h post irradiation ABA concentrations decreased. Such increments of antioxidant terpenes along with ABA suggest elicitation of mechanism of defense. The adaptative responses induced by relatively low UV-B irradiations as suggested by synthesis of terpenes related with membrane stability correlated with augments in terpene synthase activity.
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Grape responds to low intensity UV-B by increasing membrane-related triterpenes (1) suggesting acclimation, while under high UV-B treatment they accumulated terpenes with antioxidant properties (2), and the stress-hormone ABA (3), suggesting mechanisms of defense.? We investigated terpenes in grapevines exposed to UV at low and high intensities. ? Low UV-B augmented membrane triterpenes suggesting a mechanism of acclimation. ? High UV-B increased antioxidant terpenes and ABA suggesting mechanism of defense.
Publication year: 2012 Source:Phytochemistry, Volume 78 Marcio Fronza, Evelyn Lamy, Stefan Günther, Berta Heinzmann, Stefan Laufer, Irmgard Merfort Abietane diterpenes, especially those containing quinone moieties, are often reported to have cytotoxic effects on cancer cell lines. They deserve greater attention because several cancer chemotherapeutic agents also possess the quinone structural feature. To date, very little is known about their cytotoxic molecular modes of action. In the present study, five diterpenes, 7 alpha-acetoxyroyleanone, horminone, royleanone, 7-ketoroyleanone and sugiol which have been previously isolated from the medicinal plant Peltodon longipes were shown to possess cytotoxic activity against the human pancreatic cancer cell line MIA PaCa-2. 7 alpha-Acetoxyroyleanone, horminone and royleanone were demonstrated to possess alkylating properties using the nucleophile 4-(4-nitrobenzyl)pyridine. However, no clear correlation between the alkylating properties and cytotoxicity of these diterpenes was observed. Furthermore, the relaxation activity of human DNA topoisomerases I and II was found to be influenced by these compounds, with 7-ketoroyleanone and sugiol being the most active. These two diterpenes preferentially inhibited topoisomerase I and exhibited lower IC50 values than the classical topoisomerase I inhibitor camptothecin. Molecular docking studies revealed possible interactions of diterpenes with topoisomerase I, indicating that these compounds do not form the drug–enzyme–DNA covalent ternary complex as observed with camptothecin. A binding pocket located at the surface of the DNA-interaction site was proposed. Moreover, the ability of the five diterpenes to generate DNA-strand breaks in single cells was confirmed using the alkaline comet assay. As expected, these diterpenes also influenced cell cycle progression and arrested cells in different phases of the cell cycle, primarily the G1/G0 and S-phases. Interestingly, the diterpenes only exhibited a slight ability to induce apoptotic cell death and failed to generate intracellular reactive oxygen species. These results provide additional understanding of the cytotoxic effects of abietane diterpenes. Depending on their functional groups, we propose that abietane diterpenes utilise different mechanisms to induce cell death.
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Comprehensive cytotoxic studies of five abietane diterpenes from Peltodon longipes have been undertaken to get insights in their molecular mode of action.? Abietane diterpenes preferentially inhibit topoisomerase I. ? A new binding mode is described. ? Cell cycle is influenced in the G1/G0 or the S-phase. ? Induction of DNA damage is observed in the comet assay.
Publication year: 2012 Source:Phytochemistry, Volume 77 Joscelyn Sarsby, Mark W. Towers, Chris Stain, Rainer Cramer, Olga A. Koroleva Glucosinolates are multi-functional plant secondary metabolites which play a vital role in plant defence and are, as dietary compounds, important to human health and livestock well-being. Knowledge of the tissue-specific regulation of their biosynthesis and accumulation is essential for plant breeding programs. Here, we report that in Arabidopsis thaliana, glucosinolates are accumulated differentially in specific cells of reproductive organs. Using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI), distribution patterns of three selected compounds, 4-methylsulfinylbutyl (glucoraphanin), indol-3-ylmethyl (glucobrassicin), and 4-benzoyloxybutyl glucosinolates, were mapped in the tissues of whole flower buds, sepals and siliques. The results show that tissue localization patterns of aliphatic glucosinolate glucoraphanin and 4-benzoyloxybutyl glucosinolate were similar, but indole glucosinolate glucobrassicin had different localisation, indicating a possible difference in function. The high resolution images obtained by a complementary approach, cryo-SEM Energy Dispersive X-ray analysis (cryo-SEM-EDX), confirmed increased concentration of sulphur in areas with elevated amounts of glucosinolates, and allowed identifying the cell types implicated in accumulation of glucosinolates. High concentration of sulphur was found in S-cells adjacent to the phloem in pedicels and siliques, indicating the presence of glucosinolates. Moreover, both MALDI MSI and cryo-SEM-EDX analyses indicated accumulation of glucosinolates in cells on the outer surface of the sepals, suggesting that a layer of glucosinolate-accumulating epidermal cells protects the whole of the developing flower, in addition to the S-cells, which protect the phloem. This research demonstrates the high potential of MALDI MSI for understanding the cell-specific compartmentation of plant metabolites and its regulation.
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MALDI-MS imaging in combination with cryo-SEM-EDX analysis demonstrated that glucosinolates are accumulated differentially in specific cells of reproductive organs in Arabidopsis thaliana.? Three glucosinolates were mapped by MALDI-MSI in flower buds, sepals and siliques. ? Two sites of accumulation of glucosinolates were found: S-cells and epidermis of sepals. ? Accumulation of sulphur compounds in S-cells was confirmed by cryo-SEM-EDX.
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