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Phytochemistry - Current Research Articles



Current research articles: Phytochemistry

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Phytochemistry - published by Elsevier

Phytochemistry is the international journal of pure and applied plant chemistry, plant biochemistry and molecular biology.




Current articles of the journal:



Furofuran lignans display schistosomicidal and trypanocidal activities

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Márcio Luis Andrade e Silva , Viviane Rodrigues Esperandim , Daniele da Silva Ferreira , Lizandra Guidi Magalhães , Thais Coelho Lima , Wilson Roberto Cunha , Dhammika N.P. Nanayakkara , Ana Carolina Pereira , Jairo Kenupp Bastos

Parasitic diseases continue to be a major worldwide health problem, and there is an urgent need for development of therapeutic drugs. This paper describes synthesis of dehydrodiferulic acid dilactone 1 and dehydrodisinapic acid dilactone 2 furofuran lignans by oxidative coupling of ferulic and sinapic acids, respectively. Their schistosomicidal, trypanocidal, and leishmanicidal activities were evaluated in vitro against Schistosoma mansoni adult worms, trypomastigote and amastigotes forms of Trypanosoma cruzi, and promastigote forms of Leishmania amazonensis. Compound 1 did not display significant schistosomicidal activity, but it presented potent trypanocidal activity, since it induced death of trypomastigotes and amastigotes with IC50/24h of 9.3?M and 7.3?M, respectively. Compound 2 had slight trypanocidal and schistosomicidal activities. None of the compounds were active against L. amazonensis. These results demonstrated that furofuran lignans are potentially useful for anti-parasitic drugs development and should be further investigated.

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Posted on 31 October 2014 | 3:46 am


Profiling of secondary metabolites in root exudates of Arabidopsis thaliana

Publication date: Available online 29 October 2014
Source:Phytochemistry

Author(s): Nadine Strehmel , Christoph Böttcher , Stephan Schmidt , Dierk Scheel

To explore the chemical composition of root exudates of the model plant Arabidopsis thaliana a workflow for nontargeted metabolite profiling of the semipolar fraction of root exudates was developed. It comprises hydroponic plant cultivation and sampling of root exudates under sterile conditions, sample preparation by solid-phase extraction and analysis by reversed-phase UPLC/ESI-QTOFMS. Following the established workflow, root exudates of six-week-old plants were profiled and a set of reproducibly occurring molecular features was compiled. To structurally elucidate the corresponding metabolites, accurate mass tandem mass spectrometry and on-line hydrogen/deuterium exchange were applied. Currently, a total of 103 compounds were detected and annotated by elemental composition of which more than 90 were structurally characterized or classified. Among them, 42 compounds were rigorously identified using an authenticated standard. The compounds identified so far include nucleosides, deoxynucleosides, aromatic amino acids, anabolites and catabolites of glucosinolates, dipeptides, indolics, salicylic and jasmonic acid catabolites, coumarins, mono-, di- and trilignols, hydroxycinnamic acid derivatives and oxylipins and exemplify the high chemical diversity of plant root exudates.

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Posted on 31 October 2014 | 3:46 am


Graphical Contents List

Publication date: October 2014
Source:Phytochemistry, Volume 106









Posted on 31 October 2014 | 3:46 am


Galloylated flavonol rhamnosides from the leaves of Calliandra tergemina with antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA)

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Elaine Wan Ling Chan , Alexander I. Gray , John O. Igoli , Sui Mae Lee , Joo Kheng Goh

Galloylated flavonol rhamnosides identified as kaempferol-3-O-(2?,3?,4?-tri-O-galloyl)-?-l-rhamnopyranoside, quercetin-3-O-(3?,4?-di-O-galloyl)-?-l-rhamnopyranoside, and quercetin-3-O-(2?,3?,4?-tri-O-galloyl)-?-l-rhamnopyranoside, together with five known galloylated and non-galloylated flavonol rhamnosides, were isolated from leaves of Calliandra tergemina (L.) Benth. Their structures were established using spectroscopic methods and their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) were evaluated by a microdilution method.

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Posted on 31 October 2014 | 3:46 am


Graphical Contents List

Publication date: November 2014
Source:Phytochemistry, Volume 107









Posted on 31 October 2014 | 3:46 am


Steroidal glycosides from the underground parts of Dracaena thalioides and their cytotoxic activity

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Liying Tang , Zhuju Wang , Hongwei Wu , Akihito Yokosuka , Yoshihiro Mimaki

Six spirostanol glycosides (16) and 12 known compounds (718) were isolated from the underground parts of Dracaena thalioides (Agavaceae). Their structures were determined by spectroscopic analysis, including 2D NMR spectroscopic data, and chemical transformations. The isolated compounds were evaluated for cytotoxic activity against HL-60 human leukemia cells. Compounds 1, 36, and 818 showed cytotoxicity against HL-60 cells, of which 10, a bisdesmosidic spirostanol derivative, showed potent cytotoxicity against HL-60 cells with an IC50 value of 0.38?M and induced apoptosis in HL-60 cells.

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Posted on 31 October 2014 | 3:46 am


Comparative profiling of membrane lipids during water stress in Thellungiella salsuginea and its relative Arabidopsis thaliana

Publication date: Available online 9 October 2014
Source:Phytochemistry

Author(s): Buzhu Yu , Weiqi Li

The remodelling of membrane lipids contributes to the tolerance of plants to stresses, such as freezing and deprivation of phosphorus. However, whether and how this remodelling relates to tolerance of PEG-induced osmotic stress has seldom been reported. Thellungiella salsuginea is a popular extremophile model for studies of stress tolerance. In this study, it was demonstrated that T. salsuginea was more tolerant to PEG-induced osmotic stress than its close relative Arabidopsis thaliana. Lipidomic analysis indicated that plastidic lipids are more sensitive to PEG-induced osmotic stress than extra-plastidic ones in both species, and that the changes in plastidic lipids differed markedly between them. PEG-induced osmotic stress led to a dramatic decrease in levels of plastidic lipids in A. thaliana, whereas the change in plastidic lipid in T. salsuginea involved an adaptive remodelling shortly after the onset of PEG-induced osmotic stress. The two aspects of this remodelling involved increases in (1) the level of plastidic lipids, especially digalactosyl diacylglycerol, and (2) the double bond index of plastidic lipids. These remodelling steps could maintain the integrity and improve the fluidity of plastidic membranes and this may contribute to the PEG-induced osmotic stress tolerance of T. salsuginea.

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Posted on 31 October 2014 | 3:46 am


In vitro antimalarial studies of novel artemisinin biotransformed products and its derivatives

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Rashmi Gaur , Mahendra P. Darokar , P.V. Ajayakumar , Ram Sajiwan Shukla , Rajendra Singh Bhakuni

Biotransformation of antimalarial drug artemisinin by fungi Rhizopus stolonifer afforded three sesquiterpenoid derivatives. The transformed products were 1?-hydroxyartemisinin (3), 3.0%, a new compound, 10?-hydroxyartemisinin, 54.5% (4) and deoxyartemisinin (2) in 9% yield. The fungus expressed high-metabolism activity (66.5%). The chemical structures of the compounds were elucidated by 1D, 2D NMR spectrometry and mass spectral data. The major compound 10?-hydroxyartemisinin (4) was chemically converted to five new derivatives 59. All the compounds 39 were subjected for in vitro anti-malarial activity. 10?-Hydroxy-12?-arteether (8), IC50 at 18.29nM was found to be 10 times better active than its precursor 4 (184.56nM) and equipotent antimalarial with natural drug artemisinin whereas the ?-derivative 9 is 3 times better than 4 under in vitro conditions. Therefore, the major biotransformation product 4 can be exploited for further modification into new clinically potent molecules. The results show the versatility of microbial-catalyzed biotransformations leading to the introduction of a hydroxyl group at tertiary position in artemisinin in derivative (3).

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Posted on 31 October 2014 | 3:46 am


Acyl-ACP thioesterases from Camelina sativa: Cloning, enzymatic characterization and implication in seed oil fatty acid composition

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Manuel Fernando Rodríguez-Rodríguez , Joaquín J. Salas , Rafael Garcés , Enrique Martínez-Force

Acyl-acyl carrier protein (ACP) thioesterases are intraplastidial enzymes that terminate de novo fatty acid biosynthesis in the plastids of higher plants by hydrolyzing the thioester bond between ACP and the fatty acid synthesized. Free fatty acids are then esterified with coenzyme A prior to being incorporated into the glycerolipids synthesized through the eukaryotic pathway. Acyl-ACP thioesterases belong to the TE14 family of thioester-active enzymes and can be classified as FatAs and FatBs, which differ in their amino acid sequence and substrate specificity. Here, the FatA and FatB thioesterases from Camelina sativa seeds, a crop of interest in plant biotechnology, were cloned, sequenced and characterized. The mature proteins encoded by these genes were characterized biochemically after they were heterologously expressed in Escherichia coli and purified. C. sativa contained three different alleles of both the FatA and FatB genes. These genes were expressed most strongly in expanding tissues in which lipids are very actively synthesized, such as developing seed endosperm. The CsFatA enzyme displayed high catalytic efficiency on oleoyl-ACP and CsFatB acted efficiently on palmitoyl-ACP. The contribution of these two enzymes to the synthesis of C. sativa oil was discussed in the light of these results.

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Posted on 31 October 2014 | 3:46 am


Limonoids from the fruits of Melia toosendan and their NF-?B modulating activities

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Guo-Yuan Zhu , Li-Ping Bai , Liang Liu , Zhi-Hong Jiang

Eight ring C-seco and ring-intact limonoids, and 25 known limonoids were isolated from the fruits of Melia toosendan (Meliaceae). Their structures were elucidated on the basis of extensive spectroscopic evidence including HRMS, 1D and 2D NMR spectroscopic data. A total of 29 isolated limonoids was evaluated for NF-?B activities. Among them, eight compounds significantly enhanced the TNF?-induced NF-?B luciferase activity at 10?M, while 10 compounds suppressed the NF-?B activation.

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Posted on 31 October 2014 | 3:46 am


Retention time prediction for dereplication of natural products (CxHyOz) in LC–MS metabolite profiling

Publication date: Available online 28 October 2014
Source:Phytochemistry

Author(s): Philippe J. Eugster , Julien Boccard , Benjamin Debrus , Lise Bréant , Jean-Luc Wolfender , Sophie Martel , Pierre-Alain Carrupt

The detection and early identification of natural products (NPs) for dereplication purposes require efficient, high-resolution methods for the profiling of crude natural extracts. This task is difficult because of the high number of NPs in these complex biological matrices and because of their very high chemical diversity. Metabolite profiling using ultra-high pressure liquid chromatography coupled to high-resolution mass spectrometry (UHPLC–HR-MS) is very efficient for the separation of complex mixtures and provides molecular formula information as a first step in dereplication. This structural information alone or even combined with chemotaxonomic information is often not sufficient for unambiguous metabolite identification. In this study, a representative set of 260 NPs containing C, H, and O atoms only was analysed in generic UHPLC–HR-MS profiling conditions. Two easy to use quantitative structure retention relationship (QSRR) models were built based on the measured retention time and on eight simple physicochemical parameters calculated from the structures. First, an original approach using several partial least square (PLS) regressions according to the phytochemical classes provided satisfactory results with an easy calculation. Secondly, a unique artificial neural network (ANN) model provided similar results on the whole set of NPs but required dedicated software. The retention prediction methods described in this study were found to improve the level of confidence of the identification of given analytes among putative isomeric structures. Its applicability was verified for the dereplication of NPs in model plant extracts.

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Posted on 31 October 2014 | 3:46 am


Comparative analysis of CYP93E proteins for improved microbial synthesis of plant triterpenoids

Publication date: Available online 23 October 2014
Source:Phytochemistry

Author(s): Tessa Moses , Johan M. Thevelein , Alain Goossens , Jacob Pollier

Cytochrome P450-dependent monooxygenases (P450s) belonging to the CYP93E subfamily catalyze the C-24 oxidation of the triterpene backbone during the biosynthesis of triterpenoid saponins, which are bioactive plant natural products. In our attempts to produce plant triterpenoids in the yeast Saccharomyces cerevisiae, we observed a poor in vivo catalytic efficiency of the Medicago truncatula CYP93E2. To overcome this biosynthetic bottleneck, we screened publicly available plant genome and transcriptome data for CYP93E subfamily members. Six CYP93E orthologs, exclusively from leguminous plant species, were identified and functionally characterized in S. cerevisiae. Despite the high degree of amino acid conservation, the CYP93E orthologs showed large variations in enzymatic efficiency in yeast. The CYP93E9 from Phaseolus vulgaris showed the highest activity and converted ?80% of the accumulating in vivo produced substrate ?-amyrin to the products olean-12-ene-3?,24-diol and probable 3?-hydroxy olean-12-en-24-oic acid, with a catalytic efficiency that was 61 times higher than that of the M. truncatula CYP93E2. In conclusion, we have expanded the list of functional CYP93E orthologs to a total of nine proteins and show that there are large variations in their catalytic efficiencies when expressed in a heterologous host. Although demonstrated here for the CYP93E family involved in triterpenoid saponin biosynthesis, this phenomenon is undoubtedly extendable to other enzyme families involved in natural product synthesis. Hence, screening for homologous enzymes may become a valuable synthetic biologist’s tool for engineering superior production chassis.

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Posted on 31 October 2014 | 3:46 am


The red sport of ‘Zaosu’ pear and its red-striped pigmentation pattern are associated with demethylation of the PyMYB10 promoter

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Minjie Qian , Yongwang Sun , Andrew C. Allan , Yuanwen Teng , Dong Zhang

‘Zaosu’ pear, a hybrid of Pyrus pyrifolia and Pyrus communis, is a popular cultivar developed in China. ‘Zaosu Red’ is a bud sport of ‘Zaosu’ with red shoots, young leaves, and fruit. After grafting of ‘Zaosu Red’, reverse mutations in some branches lead to a loss of colour in leaves and stems. Also, the mature fruit of ‘Zaosu Red’ exhibits two phenotypes; fully red and striped. The aim of this study was to establish the mechanism of the red colour mutation in ‘Zaosu’ and the striped pigmentation pattern in fruit of ‘Zaosu Red’. The accumulation of anthocyanins and transcript levels of the genes PpUFGT2 and PyMYB10 were highly correlated. The open reading frames (ORF) and promoter regions of these two key genes were cloned and compared between ‘Zaosu’ and its bud sports, but no sequence differences were found. The R2R3 MYB, PyMYB10, can activate expression of genes encoding enzymes of the anthocyanin biosynthetic pathway. A yeast one-hybrid assay showed that PyMYB10 was associated with the ?658 to ?172bp fragment of the PpUFGT2 promoter, probably via a MYB binding site (MBS) located at ?466bp. The PyMYB10 promoter had lower methylation levels in anthocyanin-rich tissues, indicating that the red bud sport of ‘Zaosu’ pear and the striped pigmentation pattern of ‘Zaosu Red’ pear are associated with demethylation of the PyMYB10 promoter.

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Posted on 31 October 2014 | 3:46 am


Constituents of Vigna angularis and their in vitro anti-inflammatory activity

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Yong Jiang , Ke-Wu Zeng , Bruno David , Georges Massiot

Nine non-phenolic compounds, including four furanylmethyl glycosides, angularides A–D, one ent-kaurane diterpene glycoside, angularin A, and four triterpenoid saponins, angulasaponins A–D, were isolated from seeds of Vigna angularis, together with eight known compounds. Their structures were elucidated on the basis of extensive 1D and 2D NMR spectroscopic analysis as well as chemical methods. Angularin A, angulasaponins A–C, and azukisaponins III and VI showed inhibition of nitric oxide production in LPS-activated RAW264.7 macrophages, with IC50 values ranging from 13?M to 24?M.

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Posted on 31 October 2014 | 3:46 am


Terpenoids with alpha-glucosidase inhibitory activity from the submerged culture of Inonotus obliquus

Publication date: Available online 18 October 2014
Source:Phytochemistry

Author(s): You-Min Ying , Lin-Yan Zhang , Xia Zhang , Hai-Bo Bai , Dong-E Liang , Lie-Feng Ma , Wei-Guang Shan , Zha-Jun Zhan

Lanostane-type triterpenoids, inotolactones A and B, a drimane-type sesquiterpenoid, inotolactone C, and five known terpenoids 6?-hydroxy-trans-dihydroconfertifolin, inotodiol, 3?,22-dihydroxyanosta-7,9(11),24-triene, 3?-hydroxycinnamolide, and 17-hydroxy-ent-atisan-19-oic acid, were isolated from the submerged culture of chaga mushroom, Inonotus obliquus. Their structures were characterized by spectroscopic methods, including MS and NMR (1D and 2D) spectroscopic techniques. Inotolactones A and B, examples of lanostane-type triterpenoids bearing ?,?-dimethyl, ?,?-unsaturated ?-lactone side chains, exhibited more potent alpha-glucosidase inhibitory activities than the positive control acarbose. This finding might be related to the anti-hyperglycemic properties of the fungus and to its popular role as a diabetes treatment. In addition, a drimane-type sesquiterpenoid and an atisane-type diterpenoid were isolated from I. obliquus.

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Posted on 31 October 2014 | 3:46 am


Structures and biological significance of lactarane sesquiterpenes from the European mushroom Russula nobilis

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Omar Malagòn , Alessio Porta , Marco Clericuzio , Gianluca Gilardoni , Davide Gozzini , Giovanni Vidari


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Posted on 31 October 2014 | 3:46 am


Identification and cloning of an NADPH-dependent hydroxycinnamoyl-CoA double bond reductase involved in dihydrochalcone formation in Malus×domestica Borkh.

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Mwafaq Ibdah , Anna Berim , Stefan Martens , Andrea Lorena Herrera Valderrama , Luisa Palmieri , Efraim Lewinsohn , David R. Gang

The apple tree (Malus sp.) is an agriculturally and economically important source of food and beverages. Many of the health beneficial properties of apples are due to (poly)phenolic metabolites that they contain, including various dihydrochalcones. Although many of the genes and enzymes involved in polyphenol biosynthesis are known in many plant species, the specific reactions that lead to the biosynthesis of the dihydrochalcone precursor, p-dihydrocoumaroyl-CoA (3), are unknown. To identify genes involved in the synthesis of these metabolites, existing genome databases of the Rosaceae were screened for apple genes with significant sequence similarity to Arabidopsis alkenal double bond reductases. Herein described are the isolation and characterization of a Malus hydroxycinnamoyl-CoA double bond reductase, which catalyzed the NADPH-dependent reduction of p-coumaroyl-CoA and feruloyl-CoA to p-dihydrocoumaroyl-CoA and dihydroferuloyl-CoA, respectively. Its apparent K m values for p-coumaroyl-CoA, feruloyl-CoA and NADPH were 96.6, 92.9 and 101.3?M, respectively. The Malus double bond reductase preferred feruloyl-CoA to p-coumaroyl-CoA as a substrate by a factor of 2.1 when comparing catalytic efficiencies in vitro. Expression analysis of the hydroxycinnamoyl-CoA double bond reductase gene revealed that its transcript levels showed significant variation in tissues of different developmental stages, but was expressed when expected for involvement in dihydrochalcone formation. Thus, the hydroxycinnamoyl-CoA double bond reductase appears to be responsible for the reduction of the ?,?-unsaturated double bond of p-coumaroyl-CoA, the first step of dihydrochalcone biosynthesis in apple tissues, and may be involved in the production of these compounds.

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Posted on 31 October 2014 | 3:46 am


Bioactive furanocoumarins from stems of Clausena lansium

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Hang Liu , Fei Li , Chuang-Jun Li , Jing-Zhi Yang , Li Li , Nai-Hong Chen , Dong-Ming Zhang

Clausena lansium Skeels, a member of the Rutaceae, is a shrub or small tree with grapelike fruits. Several parts of this plant have been used in folk medicine. A bioactive constituent investigation of the stems of C. lansium herein resulted in isolation of four furanocoumarins, claucoumarins A–D, and 13 known analogs. Their structures were elucidated on the basis of spectroscopic analyses, including UV, IR, MS, and NMR experiments, and their absolute configurations were determined by CD experiments. Using an in vitro system, several of these compounds showed selective neuroprotective effects at a concentration of 10?M.

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Posted on 31 October 2014 | 3:46 am


Exogenous application of methyl jasmonate lowers the effect of cadmium-induced oxidative injury in rice seedlings

Publication date: Available online 6 October 2014
Source:Phytochemistry

Author(s): Indra Singh , Kavita Shah

Rice seedlings grown under 50?M cadmium alone or in combination with 5?Mmethyl jasmonate were investigated for Cd-induced oxidative injury at 3, 7 and 10days of treatment. MeJA treatments alone did not have any significant change in antioxidant enzyme activities or levels of H2O2 and O2 ? in roots/shoots, as compared to controls during 3–10days. The Cd-stressed plants When supplemented with exogenous MeJA revealed significant and consistent changes in activities of antioxidant enzymes CAT, SOD, POD and GR paralleled with an increased GSH-pools than that in plants subjected to Cd-stress alone. Synthesis of GSH driven by increasing demand for GSH in response to Cd-induced oxidative stress in rice was evident. Increased activity of LOX under Cd-stress was noted. Results suggest enhanced Cd-tolerance, lowered Cd2+ uptake, an improved membrane integrity and ‘switching on’ of the JA-biosynthesis by LOX in the Cd-stressed rice roots/shoots exposed to MeJA. Exposure to MeJA improved antioxidant response and accumulation of antioxidants which perhaps lowered the Cd-induced oxidative stress in rice. It is this switching on/off of the JA-biosynthesis and ROS mediated signal transduction pathway involving glutathione homeostasis via GR which helps MeJA to mitigate Cd-induced oxidative injury in rice.

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Posted on 31 October 2014 | 3:46 am


Distribution of toxic alkaloids in tissues from three herbal medicine Aconitum species using laser micro-dissection, UHPLC–QTOF MS and LC–MS/MS techniques

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Yogini Jaiswal , Zhitao Liang , Alan Ho , LaiLai Wong , Peng Yong , Hubiao Chen , Zhongzhen Zhao

Aconite poisoning continues to be a major type of poisoning caused by herbal drugs in many countries. Nevertheless, despite its toxic characteristics, aconite is used because of its valuable therapeutic benefits. The aim of the present study was to determine the distribution of toxic alkaloids in tissues of aconite roots through chemical profiling. Three species were studied, all being used in traditional Chinese Medicine (TCM) and traditional Indian medicine (Ayurveda), namely: Aconitum carmichaelii, Aconitum kusnezoffii and Aconitum heterophyllum. Laser micro-dissection was used for isolation of target microscopic tissues, such as the metaderm, cortex, xylem, pith, and phloem, with ultra-high performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry (UHPLC–QTOF MS) employed for detection of metabolites. Using a multi-targeted approach through auto and targeted LC–MS/MS, 48 known compounds were identified and the presence of aconitine, mesaconitine and hypaconitine that are the biomarkers of this plant was confirmed in the tissues. These results suggest that the three selected toxic alkaloids were exclusively found in A. carmichaelii and A. kusnezoffii. The most toxic components were found in large A. carmichaelii roots with more lateral root projections, and specifically in the metaderm, cork and vascular bundle tissues. The results from metabolite profiling were correlated with morphological features to predict the tissue specific distribution of toxic components and toxicity differences among the selected species. By careful exclusion of tissues having toxic diester diterpenoid alkaloids, the beneficial effects of aconite can still be retained and the frequency of toxicity occurrences can be greatly reduced. Knowledge of tissue-specific metabolite distribution can guide users and herbal drug manufacturers in prudent selection of relatively safer and therapeutically more effective parts of the root. The information provided from this study can contribute towards improved and effective management of therapeutically important, nonetheless, toxic drug such as Aconite.

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Posted on 31 October 2014 | 3:46 am


Occurrence of polyamines in root nodules of Phaseolus vulgaris in symbiosis with Rhizobium tropici in response to salt stress

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Miguel López-Gómez , Libertad Cobos-Porras , Javier Hidalgo-Castellanos , Carmen Lluch

Polyamines (PAs) are low molecular weight aliphatic compounds that have been shown to be an important part of plant responses to salt stress. For that reason in this work we have investigated the involvement of PAs in the response to salt stress in root nodules of Phaseolus vulgaris in symbiosis with Rhizobium tropici. The level and variety of PAs was higher in nodules, compared to leaves and roots, and in addition to the common PAs (putrescine, spermidine and spermine) we found homospermidine (Homspd) as the most abundant polyamine in nodules. UPLC-mass spectrometry analysis revealed the presence of 4-aminobutylcadaverine (4-ABcad), only described in nodules of Vigna angularis before. Indeed, the analysis of different nodular fractions revealed higher level of 4-ABcad, as well as Homspd, in bacteroids which indicate the production of these PAs by the bacteria in symbiosis. The genes involved in PAs biosynthesis in nodules displayed an induction under salt stress conditions which was not consistent with the decline of free PAs levels, probably due to the nitrogen limitations provoked by the nitrogenase activity depletion and/or the conversion of free PAs to theirs soluble conjugated forms, that seems to be one of the mechanisms involved in the regulation of PAs levels. On the contrary, cadaverine (Cad) and 4-ABcad concentrations augmented by the salinity, which might be due to their involvement in the response of bacteroids to hyper-osmotic conditions. In conclusion, the results shown in this work suggest the alteration of the bacteroidal metabolism towards the production of uncommon PAs such as 4-ABcad in the response to salt stress in legume root nodules.

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Posted on 31 October 2014 | 3:46 am


Steroidal saponins from Tribulus terrestris

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Li-Ping Kang , Ke-Lei Wu , He-Shui Yu , Xu Pang , Jie Liu , Li-Feng Han , Jie Zhang , Yang Zhao , Cheng-Qi Xiong , Xin-Bo Song , Chao Liu , Yu-Wen Cong , Bai-Ping Ma

Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-2?,3?,22?,26-tetrol-12-one (terrestrinin C), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin D), 26-O-?-d-glucopyranosyl-(25S)-furost-4-en-22?,26-diol-3,6,12-trione (terrestrinin E), 26-O-?-d-glucopyranosyl-(25R)-5?-furostan-3?,22?,26-triol-12-one (terrestrinin F), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-12?,22?,26-triol-3-one (terrestrinin G), 26-O-?-d-glucopyranosyl-(1?6)-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin H), and 24-O-?-d-glucopyranosyl-(25S)-5?-spirostan-3?,24?-diol-12-one-3-O-?-d-glucopyranosyl-(1?4)-?-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation.

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Posted on 31 October 2014 | 3:46 am


Editorial Board/Publication Information

Publication date: November 2014
Source:Phytochemistry, Volume 107









Posted on 31 October 2014 | 3:46 am


Comparison of the chemical composition of three species of smartweed (genus Persicaria) with a focus on drimane sesquiterpenoids

Publication date: Available online 29 October 2014
Source:Phytochemistry

Author(s): N. Prota , R. Mumm , H.J. Bouwmeester , M.A. Jongsma

The genus Persicaria is known to include species accumulating drimane sesquiterpenoids, but a comparative analysis highlighting the compositional differences has not been done. In this study, the secondary metabolites of both flowers and leaves of Persicaria hydropiper, Persicaria maculosa and Persicaria minor, three species which occur in the same habitat, were compared. Using gas chromatography–mass spectrometry (GC–MS) analysis of extracts, overall 21/29 identified compounds in extracts were sesquiterpenoids and 5/29 were drimanes. Polygodial was detected in all species, though not in every sample of P. maculosa. On average, P. hydropiper flowers contained about 6.2mggFW?1 of polygodial, but P. minor flowers had 200-fold, and P. maculosa 100,000 fold lower concentrations. Comparatively, also other sesquiterpenes were much lower in those species, suggesting the fitness benefit to depend on either investing a lot or not at all in terpenoid-based secondary defences. For P. hydropiper, effects of flower and leaf development and headspace volatiles were analysed as well. The flower stage immediately after fertilisation was the one with the highest content of drimane sesquiterpenoids and leaves contained about 10-fold less of these compounds compared to flowers. The headspace of P. hydropiper contained 8 compounds: one monoterpene, one alkyl aldehyde and six sesquiterpenes, but none were drimanes. The potential ecological significance of the presence or absence of drimane sesquiterpenoids and other metabolites for these plant species are discussed.

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Posted on 31 October 2014 | 3:46 am


Arachidonic acid-dependent carbon-eight volatile synthesis from wounded liverwort (Marchantia polymorpha)

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Hirotomo Kihara , Maya Tanaka , Katsuyuki T. Yamato , Akira Horibata , Atsushi Yamada , Sayaka Kita , Kimitsune Ishizaki , Masataka Kajikawa , Hideya Fukuzawa , Takayuki Kohchi , Yoshihiko Akakabe , Kenji Matsui

Eight-carbon (C8) volatiles, such as 1-octen-3-ol, octan-3-one, and octan-3-ol, are ubiquitously found among fungi and bryophytes. In this study, it was found that the thalli of the common liverwort Marchantia polymorpha, a model plant species, emitted high amounts of C8 volatiles mainly consisting of (R)-1-octen-3-ol and octan-3-one upon mechanical wounding. The induction of emission took place within 40min. In intact thalli, 1-octen-3-yl acetate was the predominant C8 volatile while tissue disruption resulted in conversion of the acetate to 1-octen-3-ol. This conversion was carried out by an esterase showing stereospecificity to (R)-1-octen-3-yl acetate. From the transgenic line of M. polymorpha (des6KO ) lacking arachidonic acid and eicosapentaenoic acid, formation of C8 volatiles was only minimally observed, which indicated that arachidonic and/or eicosapentaenoic acids were essential to form C8 volatiles in M. polymorpha. When des6KO thalli were exposed to the vapor of 1-octen-3-ol, they absorbed the alcohol and converted it into 1-octen-3-yl acetate and octan-3-one. Therefore, this implied that 1-octen-3-ol was the primary C8 product formed from arachidonic acid, and further metabolism involving acetylation and oxidoreduction occurred to diversify the C8 products. Octan-3-one was only minimally formed from completely disrupted thalli, while it was formed as the most abundant product in partially disrupted thalli. Therefore, it is assumed that the remaining intact tissues were involved in the conversion of 1-octen-3-ol to octan-3-one in the partially disrupted thalli. The conversion was partly promoted by addition of NAD(P)H into the completely disrupted tissues, suggesting an NAD(P)H-dependent oxidoreductase was involved in the conversion.

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Posted on 31 October 2014 | 3:46 am


The crucial role of ?- and K-segments in the in vitro functionality of Vitis vinifera dehydrin DHN1a

Publication date: Available online 29 October 2014
Source:Phytochemistry

Author(s): Raquel Rosales , Irene Romero , Mª Isabel Escribano , Carmen Merodio , Mª Teresa Sanchez-Ballesta

Dehydrins (DHNs), group II LEA (Late Embryogenesis Abundant) proteins, are among the most commonly observed proteins which accumulate in plants in response to cold and any other environmental factors, causing the dehydration of cells. In previous studies, we isolated a YSK2-type VvcDHN1a gene from table grapes (Vitis vinifera cv. Cardinal) which presented two spliced variants (the spliced, DHN1a_s and the unspliced, DHN1a_u). Their expression was induced by low temperature storage and CO2, although with different accumulation patterns. DHN1a_u codifies for a truncated YS protein lacking ?- and K-segments, which might affect its functionality. In this work, we expressed both DHN1a_s and DHN1a_u recombinant proteins in Escherichia coli. We carried out a number of in vitro assays to analyze the implications that ?- and K-segments have in the protective role of VvcDHN1 against different abiotic stresses and their antifungal activity against the fungal pathogen Botrytis cinerea. Our results showed that unlike DHN1a_u, DHN1a_s has a potent cryoprotective effect on lactate dehydrogenase activity, protects malate dehydrogenase against dehydration and partially inhibits B. cinerea growth. Moreover, the DHN1a promoter presented cis-regulatory elements related to cold and drought, as well as biotic stress-related elements. We also observed that both spliced variants interact weakly with DNA, suggesting that K-segments are not involved in DNA binding. Overall, this work highlights the crucial role of ?- and K-segments in DHNs function in plant response to abiotic stress showing for the first time, the potential role of the V. vinifera DHN1a_s in the protection against freezing and dehydration as well as inhibiting B. cinerea growth.

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Posted on 31 October 2014 | 3:46 am


Global diversity of the Ganoderma lucidum complex (Ganodermataceae, Polyporales) inferred from morphology and multilocus phylogeny

Publication date: Available online 25 October 2014
Source:Phytochemistry

Author(s): Li-Wei Zhou , Yun Cao , Sheng-Hua Wu , Josef Vlasák , De-Wei Li , Meng-Jie Li , Yu-Cheng Dai

Species of the Ganoderma lucidum complex are used in many types of health products. However, the taxonomy of this complex has long been chaotic, thus limiting its uses. In the present study, 32 collections of the complex from Asia, Europe and North America were analyzed from both morphological and molecular phylogenetic perspectives. The combined dataset, including an outgroup, comprised 33 ITS, 24 tef1?, 24 rpb1 and 21 rpb2 sequences, of which 19 ITS, 20 tef1?, 20 rpb1 and 17 rpb2 sequences were newly generated. A total of 13 species of the complex were recovered in the multilocus phylogeny. These 13 species were not strongly supported as a single monophyletic lineage, and were further grouped into three lineages that cannot be defined by their geographic distributions. Clade A comprised Ganoderma curtisii, Ganoderma flexipes, Ganoderma lingzhi, Ganoderma multipileum, Ganoderma resinaceum, Ganoderma sessile, Ganoderma sichuanense and Ganoderma tropicum, Clade B comprised G. lucidum, Ganoderma oregonense and Ganoderma tsugae, and Clade C comprised Ganoderma boninense and Ganoderma zonatum. A dichotomous key to the 13 species is provided, and their key morphological characters from context, pores, cuticle cells and basidiospores are presented in a table. The taxonomic positions of these species are briefly discussed. Noteworthy, the epitypification of G. sichuanense is rejected.

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Highlights

Ganoderma lingzhi is the most widely cultivated medicinal species within the Ganoderma lucidum complex, within which 13 species have been recognized from morphology and phylogeny.





Posted on 31 October 2014 | 3:46 am


Distinct catalytic capacities of two aluminium-repressed Arabidopsis thaliana xyloglucan endotransglucosylase/hydrolases, XTH15 and XTH31, heterologously produced in Pichia

Publication date: Available online 27 October 2014
Source:Phytochemistry

Author(s): Yuan Zhi Shi , Xiao Fang Zhu , Janice G. Miller , Timothy Gregson , Shao Jian Zheng , Stephen C. Fry

Xyloglucan plays an important structural role in primary cell walls, possibly tethering adjacent microfibrils and restraining cell expansion. There is therefore considerable interest in understanding the role of xyloglucan endotransglucosylase/hydrolases (XTHs), which are encoded in Arabidopsis by a 33-member gene family. We compared the key catalytic properties of two very different Arabidopsis XTHs (heterologously produced in Pichia), both of which are aluminium-repressed. Reductively tritiated oligosaccharides of xyloglucan were used as model acceptor substrates. Untransformed Pichia produced no xyloglucan-acting enzymes; therefore purification of the XTHs was unnecessary. XTH15, a classical group-I/II XTH, had high XET and undetectable XEH activity in vitro; its XET K m values were 31?M XXXGol (acceptor substrate) and 2.9mg/ml xyloglucan (donor substrate). In contrast, XTH31, a group-III-A XTH, showed predominant XEH activity and only slight XET activity in vitro; its XET K m was 86?M XXXGol (acceptor), indicating a low affinity of this predominantly hydrolytic protein for a transglycosylation acceptor substrate. The K m of XTH31’s XEH activity was 1.6mg/ml xyloglucan. For both proteins, the preferred XET acceptor substrate, among five cellotetraitol-based oligosaccharides tested, was XXXGol. XTH31’s XET activity was strongly compromised when the second Xyl residue was galactosylated. XTH15’s XET activity, in contrast, tolerated substitution at the second Xyl residue. The two enzymes also showed different pH preferences, XTH31 exhibiting an unusually low pH optimum and XTH15 an unusually broad optimum. XTH31’s hydrolase activity increased almost linearly with decreasing pH in the apoplastic range, 6.2–4.5, consistent with a possible role in ‘acid growth’. In conclusion, these two Al3+-repressed XTHs differ, in several important enzymic features, from other members of the Arabidopsis XTH family.

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Posted on 31 October 2014 | 3:46 am


Effect of light, methyl jasmonate and cyclodextrin on production of phenolic compounds in hairy root cultures of Scutellaria lateriflora

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Zachary Marsh , Tianhong Yang , Luis Nopo-Olazabal , Shuchi Wu , Taylor Ingle , Nirmal Joshee , Fabricio Medina-Bolivar

Scutellaria lateriflora (American skullcap) has been used in traditional medicine to treat several medical conditions including nervous disorders and cancer. Previous studies have associated these medicinal properties to flavones present in roots and leaves of this species. In order to develop a production system and study the biosynthesis of these bioactive compounds, hairy root cultures of S. lateriflora were established and line 4 was selected for further studies based on its growth performance in a modified Murashige and Skoog’s medium supplemented with 0.5mg/l indole-3-butyric acid. Scanning electron microscopy of the hairy roots showed a high profusion of hairs along the root. Several phenolic compounds, including verbascoside, and the flavones wogonin, baicalein, scutellarein and their respective glucuronides were identified by high performance liquid chromatography–tandem mass spectrometry in the root tissue, but not in the culture medium. Among these compounds, verbascoside accumulated at the highest levels. Interestingly, cultures incubated under continuous light and treated with 15mM methyl-?-cyclodextrin for 24h produced significantly higher levels of the aglycones, baicalein and wogonin, but not scutellarein, compared to cultures incubated under continuous darkness. This work demonstrates that hairy root cultures of S. lateriflora have the biosynthetic capacity to produce known Scutellaria flavones and suggest that light may have a selected regulatory effect on the synthesis or accumulation of these phenolic compounds.

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Posted on 31 October 2014 | 3:46 am


The plant cell wall integrity maintenance mechanism – A case study of a cell wall plasma membrane signaling network

Publication date: Available online 23 October 2014
Source:Phytochemistry

Author(s): Thorsten Hamann

Some of the most important functions of plant cell walls are protection against biotic/abiotic stress and structural support during growth and development. A prerequisite for plant cell walls to perform these functions is the ability to perceive different types of stimuli in both qualitative and quantitative manners and initiate appropriate responses. The responses in turn involve adaptive changes in cellular and cell wall metabolism leading to modifications in the structures originally required for perception. While our knowledge about the underlying plant mechanisms is limited, results from Saccharomyces cerevisiae suggest the cell wall integrity maintenance mechanism represents an excellent example to illustrate how the molecular mechanisms responsible for stimulus perception, signal transduction and integration can function. Here I will review the available knowledge about the yeast cell wall integrity maintenance system for illustration purposes, summarize the limited knowledge available about the corresponding plant mechanism and discuss the relevance of the plant cell wall integrity maintenance mechanism in biotic stress responses.

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Posted on 31 October 2014 | 3:46 am


Triterpene glycosides and other polar constituents of shea (Vitellaria paradoxa) kernels and their bioactivities

Publication date: Available online 21 October 2014
Source:Phytochemistry

Author(s): Jie Zhang , Masahiro Kurita , Takuro Shinozaki , Motohiko Ukiya , Ken Yasukawa , Naoto Shimizu , Harukuni Tokuda , Eliot T. Masters , Momoko Akihisa , Toshihiro Akihisa

The MeOH extract of defatted shea (Vitellaria paradoxa; Sapotaceae) kernels was investigated for its constituents, and fifteen oleanane-type triterpene acids and glycosides, two steroid glucosides, two pentane-2,4-diol glucosides, seven phenolic compounds, and three sugars, were isolated. The structures of five triterpene glycosides were elucidated on the basis of spectroscopic and chemical methods. Upon evaluation of the bioactivity of the isolated compounds, it was found that some or most of the compounds have potent or moderate inhibitory activities against the following: melanogenesis in B16 melanoma cells induced by ?-melanocyte-stimulating hormone (?-MSH); generation of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, against Epstein–Barr virus early antigen (EBV-EA) activation induced by 12-O-teradecanoylphorbol 13-acetate (TPA) in Raji cells; t TPA-induced inflammation in mice, and proliferation of one or more of HL-60, A549, AZ521, and SK-BR-3 human cancer cell lines, respectively. Western blot analysis established that paradoxoside E inhibits melanogenesis by regulation of expression of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1) and TRP-2. In addition, tieghemelin A was demonstrated to exhibit cytotoxic activity against A549 cells (IC50 13.5?M) mainly due to induction of apoptosis by flow cytometry. The extract of defatted shea kernels and its constituents may be, therefore, valuable as potential antioxidant, anti-inflammatory, skin-whitening, chemopreventive, and anticancer agents.

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Highlights

Ttriterpene glycosides and other polar compounds isolated from the extract of defatted shea (Vitellaria paradoxa; Sapotaceae) kernels exhibited inhibitory activities against melanogenesis, TPA-induced EBV-EA activation, and TPA-induced inflammation in mice, as well as DPPH free-radical-scavenging and cytotoxic activities.





Posted on 31 October 2014 | 3:46 am


The fungal leaf endophyte Paraconiothyrium variabile specifically metabolizes the host-plant metabolome for its own benefit

Publication date: Available online 21 October 2014
Source:Phytochemistry

Author(s): Yuan Tian , Séverine Amand , Didier Buisson , Caroline Kunz , François Hachette , Joëlle Dupont , Bastien Nay , Soizic Prado

Fungal endophytes live inside plant tissues and some have been found to provide benefits to their host. Nevertheless, their ecological impact is not adequately understood. Considering the fact that endophytes are continuously interacting with their hosts, it is conceivable that both partners have substantial influence on each other’s metabolic processes. In this context, we have investigated the action of the endophytic fungus Paraconiothyrium variabile, isolated from the leaves of Cephalotaxus harringtonia, on the secondary metabolome of the host-plant. The alteration of the leaf compounds by the fungus was monitored through metabolomic approaches followed by structural characterization of the altered products. Out of more than a thousand molecules present in the crude extract of the plant leaf, we have observed a specific biotransformation of glycosylated flavonoids by the endophyte. In all cases it led to the production of the corresponding aglycone via deglycosylation. The deglycosylated flavonoids turned out to display significant beneficial effects on the hyphal growth of germinated spores. Our finding, along with the known allelopathic role of flavonoids, illustrates the chemical cooperation underlying the mutualistic relationship between the plant and the endophyte.

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Posted on 31 October 2014 | 3:46 am


Flavonol glycosides in the petal of Rosa species as chemotaxonomic markers

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Ochir Sarangowa , Tsutomu Kanazawa , Makoto Nishizawa , Takao Myoda , Changxi Bai , Takashi Yamagishi

Thirteen flavonol glycosides were isolated from the petals of Rosa species belonging to the section Gallicanae, and their structures were identified from their spectroscopic data. These flavonol glycosides, along with two flavonol glycosides isolated from Rosa rugosa, in the petals of 31 Rosa species belonging to sections Gallicanae, Cinnamomeae, Caninae, and Synstylae were quantitatively analyzed by UPLC. The results indicated that the species belonging to these sections could be classified into four types (Type A, B, C and D) based on the pattern of flavonol glycoside contents, whereas the R. rugosa flavonol glycosides were detected only in section Cinnamomeae. A principal components analysis (PCA) calculated from the 15 flavonol glycosides contained in these samples supported the presence of four types. The distribution of the species in Type D (a group of Cinnamomeae) was shown to reflect close interrelationships, but species in Type B (one group of Gallicanae) could be subdivided into two groups, one of which contained species in section Synstylae. Moreover, the flavonol glycosides were grouped by sugar moieties: a disaccharide composed of two hexoses (S1), a hexose (S2), including a hexose with galloyl group, a pentose (S3), and a disaccharide composed of a hexose and a pentose (S4). The ratios of the amounts of S1S4 to total flavonol glycoside content indicated that differences among the four sections were more distinctive than the amounts of the 15 flavonol glycosides. The 31 samples were divided into Type B, composed of one type of Gallicanae and Synstylae, Type A+C, composed of another type of Gallicanae and Caninae, and Type D, composed of Cinnamomeae. The R. rugosa flavonol glycosides were shown to be important chemotaxonomic markers for the classification of species in Cinnamomeae, and this method of using flavonol glycosides as chemotaxonomic markers could be useful for the identification of Rosa species belonging to sections Gallicanae, Cinnamomeae, Caninae, and Synstylae.

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Posted on 31 October 2014 | 3:46 am


Heliolactone, a non-sesquiterpene lactone germination stimulant for root parasitic weeds from sunflower

Publication date: Available online 19 October 2014
Source:Phytochemistry

Author(s): Kotomi Ueno , Toshio Furumoto , Shuhei Umeda , Masaharu Mizutani , Hirosato Takikawa , Rossitza Batchvarova , Yukihiro Sugimoto

Root exudates of sunflower (Helianthus annuus L.) line 2607A induced germination of seeds of root parasitic weeds Striga hermonthica, Orobanche cumana, Orobanche minor, Orobanche crenata, and Phelipanche aegyptiaca. Bioassay-guided purification led to the isolation of a germination stimulant designated as heliolactone. FT-MS analysis indicated a molecular formula of C20H24O6. Detailed NMR spectroscopic studies established a methylfuranone group, a common structural component of strigolactones connected to a methyl ester of a C14 carboxylic acid via an enol ether bridge. The cyclohexenone ring is identical to that of 3-oxo-?-ionol and the other part of the molecule corresponds to an oxidized carlactone at C-19. It is a carlactone-type molecule and functions as a germination stimulant for seeds of root parasitic weeds. Heliolactone induced seed germination of the above mentioned root parasitic weeds, while dehydrocostus lactone and costunolide, sesquiterpene lactones isolated from sunflower root exudates, were effective only on O. cumana and O. minor. Heliolactone production in aquacultures increased when sunflower seedlings were grown hydroponically in tap water and decreased on supplementation of the culture with either phosphorus or nitrogen. Costunolide, on the other hand, was detected at a higher concentration in well-nourished medium as opposed to nutrient-deficient media, thus suggesting a contrasting contribution of heliolactone and the sesquiterpene lactone to the germination of O. cumana under different soil fertility levels.

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Posted on 31 October 2014 | 3:46 am


Reactive oxygen species in cell wall metabolism and development in plants

Publication date: Available online 17 October 2014
Source:Phytochemistry

Author(s): Anna Kärkönen , Kazuyuki Kuchitsu

Although reactive oxygen species (ROS) are highly toxic substances that are produced during aerobic respiration and photosynthesis, many studies have demonstrated that ROS, such as superoxide anion radical ( O 2 - ) and hydrogen peroxide (H2O2), are produced in the plant cell wall in a highly regulated manner. These molecules are important signalling messengers playing key roles in controlling a broad range of physiological processes, such as cellular growth and development, as well as adaptation to environmental changes. Given the toxicity of ROS, especially of hydroxyl radical ( OH), the enzymatic ROS production needs to be tightly regulated both spatially and temporally. Respiratory burst oxidase homologues (Rboh) have been identified as ROS-producing NADPH oxidases, which act as key signalling nodes integrating multiple signal transduction pathways in plants. Also other enzyme systems, such as class III peroxidases, amine oxidases, quinone reductases and oxalate oxidases contribute to apoplastic ROS production, some especially in certain plant taxa. Here we discuss the interrelationship among different enzymes producing ROS in the plant cell wall, as well as the physiological roles of the ROS produced.

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Posted on 31 October 2014 | 3:46 am


Corynanthean, eburnan, secoleuconoxine, and pauciflorine alkaloids from Kopsia pauciflora

Publication date: Available online 17 October 2014
Source:Phytochemistry

Author(s): Chew-Yan Gan , K. Yoganathan , Kae-Shin Sim , Yun-Yee Low , Siew-Huah Lim , Toh-Seok Kam

Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo.

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Posted on 31 October 2014 | 3:46 am


Chemical taxonomy of tree peony species from China based on root cortex metabolic fingerprinting

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Chunnian He , Bing Peng , Yang Dan , Yong Peng , Peigen Xiao

The section Moutan of the genus Paeonia consists of eight species that are confined to a small area in China. A wide range of metabolites, including monoterpenoid glucosides, flavonoids, tannins, stilbenes, triterpenoids, steroids, paeonols, and phenols, have been found in the species belonging to section Moutan. However, although previous studies have analyzed the metabolites found in these species, the metabolic similarities that can be used for the chemotaxonomic distinction of section Moutan species are not yet clear. In this study, HPLC–DAD-based metabolic fingerprinting was applied to the classification of eight species: Paeonia suffruticosa, Paeonia qiui, Paeonia ostii, Paeonia rockii, Paeonia jishanensis, Paeonia decomposita, Paeonia delavayi, and Paeonia ludlowii. In total, of the 47 peaks that exhibited an occurrence frequency of 75% in all 23 tree peony samples, 43 of these metabolites were identified according to their retention times and UV absorption spectra, together with combined HPLC–QTOF-MS. These data were compared with reference standard compounds. The 43 isolated compounds included 17 monoterpenoid glucosides, 11 galloyl glucoses, 5 flavonoids, 6 paeonols and 4 phenols. Principal component analysis (PCA), and hierarchical cluster analysis (HCA), showed a clear separation between the species based on metabolomics similarities and four groups were identified. The results exhibited good agreement with the classical classification based on the morphological characteristics and geographical distributions of the subsections Vaginatae F.C. Stern and Delavayanae F.C. Stern with the exception of P. decomposita, which was found to be a transition species between these two subsections. According to their metabolic fingerprinting characteristics, P. ostii and P. suffruticosa can be considered one species, and this result is consistent with the viewpoint of medicinal plant scientists but different from that of classical morphological processing. Significantly large variations were obtained in the metabolic profiles of P. delavayi, whereas no significant difference was found between P. delavayi and P. ludlowii. This indicates that these two species have a close genetic relationship. In conclusion, the combination of HPLC–DAD and multivariate analyses has great potential for guiding future chemotaxonomic studies to examine the potential pharmaceutical value of the effective constituents of tree peony species and appears to be able to clarify the confusion and skepticism associated with the reported morphology- and molecular phylogenetics-based taxonomy of tree peonies.

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Posted on 31 October 2014 | 3:46 am


One strain-many compounds (OSMAC) method for production of polyketides, azaphilones, and an isochromanone using the endophytic fungus Dothideomycete sp.

Publication date: Available online 10 October 2014
Source:Phytochemistry

Author(s): Ranuka T. Hewage , Thammarat Aree , Chulabhorn Mahidol , Somsak Ruchirawat , Prasat Kittakoop

Polyketides 16 were produced by a one strain-many compounds (OSMAC) approach using the endophytic fungus Dothideomycete sp. CRI7 as a producer. Metabolite production of the fungus Dothideomycete sp. CRI7 was sensitive to sources of potato and malt extract used for the preparation of PDB and Czapek malt media, respectively. Three hitherto unknown metabolites were obtained from the fungus CRI7 grown in PDB medium prepared from a commercial potato powder instead of fresh tubers of potato, while three others were obtained from the fungus cultivated in Czapek malt medium. Moreover, a source of malt extract used in the Czapek malt medium was found to influence metabolite production by the fungus CRI7. Structure elucidation of these compounds was achieved by analysis of spectroscopic data, as well as by single crystal X-ray analysis. Two of the compounds showed weak cytotoxic activity, while the remainders were inactive toward the cell lines tested. One compound exhibited radical scavenging activity with an IC50 value of 21.7?M, and inhibited aromatase with an IC50 value of 12.3?M.

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Highlights

Polyketides (13), an isochromanone 4, and azaphilone 5 and 6 are produced by one strain-many compounds (OSMAC) approach. Metabolite production of the fungus Dothideomycete sp. depends on culture media and source of potato and malt extracts used for the preparation of media.





Posted on 31 October 2014 | 3:46 am


The metabolomics of oxidative stress

Publication date: Available online 8 October 2014
Source:Phytochemistry

Author(s): Graham Noctor , Caroline Lelarge-Trouverie , Amna Mhamdi

Oxidative stress resulting from increased availability of reactive oxygen species (ROS) is a key component of many responses of plants to challenging environmental conditions. The consequences for plant metabolism are complex and manifold. We review data on small compounds involved in oxidative stress, including ROS themselves and antioxidants and redox buffers in the membrane and soluble phases, and we discuss the wider consequences for plant primary and secondary metabolism. While metabolomics has been exploited in many studies on stress, there have been relatively few non-targeted studies focused on how metabolite signatures respond specifically to oxidative stress. As part of the discussion, we present results and reanalyze published datasets on metabolite profiles in catalase-deficient plants, which can be considered to be model oxidative stress systems. We emphasize the roles of ROS-triggered changes in metabolites as potential oxidative signals, and discuss responses that might be useful as markers for oxidative stress. Particular attention is paid to lipid-derived compounds, the status of antioxidants and antioxidant breakdown products, altered metabolism of amino acids, and the roles of phytohormone pathways.

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Posted on 31 October 2014 | 3:46 am


Plastochromanol-8: Fifty years of research

Publication date: Available online 9 October 2014
Source:Phytochemistry

Author(s): Jerzy Kruk , Renata Szyma?ska , Jana Cela , Sergi Munne-Bosch

Plastochromanol-8 (PC-8) is an antioxidant that, together with tocopherols and tocotrienols, belongs to the group of tocochromanols. Plastochromanol-8 has been found to occur in several plant species, including mosses, and lichens. PC-8 is found in seeds, leaves and other organs of higher plants. In leaves, PC-8 is restricted to chloroplasts. The identification of tocopherol cyclase (VTE1) as the key enzyme in the biosynthesis of PC-8 suggests that plastoglobules are the primary site of its biosynthesis. Other enzymes related with PC-8 biosynthesis in plastoglobules include: NDC1 and the ABC1-like kinase ABC1K3. The antioxidant properties of PC-8 are similar to those of other chloroplastic antioxidants in polar solvents but considerably they are enhanced in hydrophobic environments, suggesting that the unsaturated side chain performs some quenching activity. As a result of a non-enzymatic reaction, singlet oxygen can oxidize any of the 8 double bonds in the side chain of PC-8, giving at least eight hydroxy-PC-8 isomers. This review summarizes current evidence of a widespread distribution of PC-8 in photosynthetic organisms, as well as the contribution of PC-8 to the pool of lipid-soluble antioxidants in both leaves and seeds.

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Posted on 31 October 2014 | 3:46 am


Influence of seasonal variation on Thymus longicaulis C. Presl chemical composition and its antioxidant and anti-inflammatory properties

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Silvia Galasso , Severina Pacifico , Nadine Kretschmer , San-Po Pan , Sabina Marciano , Simona Piccolella , Pietro Monaco , Rudolf Bauer

Thymus longicaulis C. Presl. (Lamiaceae) is a small aromatic perennial herb typical of the Illyric-Mediterranean flora, traditionally used as remedy for cold, flu, cough, nephritis and abdominal pain. In order to carry out a thorough chemical and biological screening of the plant and to explore phenophases influence on its polyphenol content, samples of the plant were collected at different phases during its life cycle (July/October 2012 and January/April 2013). Each sample, previously extracted using a hydroalcoholic solution, was phytochemically analyzed for its metabolic constitution applying LC-DAD-ESI-MS/MS techniques. Although identified metabolites were differently concentrated at the various collection times, T. longicaulis leaf extracts were mainly constituted by low molecular weight phenols, and flavonoids. Rosmarinic acid was found as the main metabolite in Oct12 sample. Chemopreventive efficacy of the investigated extracts, by means of their anti-inflammatory, cytotoxic and antioxidant activities, was assessed. To this purpose, each extract underwent an extensive screening towards five human cell lines: CCRF-CEM (leukemia); U251 (glioblastoma); MDA-MB-231 (breast cancer); HCT-116 (colon cancer) and MRC-5 (lung fibroblasts) through XTT [2,3bis(2-metoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H tetrazolium hydroxide] test. The ability of the extracts to counteract cyclooxygenase-2 (COX-2) expression was also evaluated by COX-2 expression assay in human THP-1 monocyte-derived macrophages. COX-2 inhibition could represent a valuable anticancer strategy as it is associated with carcinogenesis and over-expressed in a variety of human malignancies. Oct12 extract, which was particularly rich in rosmarinic acid and methylapigenin, exhibited a strong antioxidant and anti-inflammatory effectiveness.

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Highlights

Thymus longicaulis C. Presl samples, collected at different phenological stages, were analyzed for their chemical composition and antioxidant and anti-inflammatory properties. The hydroalcoholic extract from plants collected in the month of October contained a large amount of rosmarinic acid and methylapigenin and showed the highest antioxidant and anti-inflammatory activities.





Posted on 31 October 2014 | 3:46 am


Comparative LC–MS-based metabolite profiling of the ancient tropical rainforest tree Symphonia globulifera

Publication date: Available online 6 October 2014
Source:Phytochemistry

Author(s): Kévin Cottet , Grégory Genta-Jouve , Yann Fromentin , Guillaume Odonne , Christophe Duplais , Olivier Laprévote , Sylvie Michel , Marie-Christine Lallemand

In the last few years, several phytochemical studies have been undertaken on the tropical tree Symphonia globulifera leading to the isolation and characterisation of several compounds exhibiting antiparasitic activities against Plasmodium falciparum, Trypanosoma brucei and Leishmania donovani. The comparative LC–MS based metabolite profiling study conducted on the tree led to the identification of compounds originating from specific tissues. The results showed that renewable organs/tissues can be used as the starting material for the production of polycyclic poly-prenylated-acylphloroglucinols, therefore reducing impacts on biodiversity. This study also underlined the lack of knowledge on the secondary metabolites produced by S. globulifera since only a small number of the total detected features were putatively identified using the database of known compounds for the species.

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Highlights

The comparative LC–MS based metabolite profiling study conducted on the tree led to the identification of tissues specific compounds. The results showed that renewable organs/tissues can be used as starting material for the production of PPAPs reducing the impact on the biodiversity.





Posted on 31 October 2014 | 3:46 am


Natural daucane esters induces apoptosis in leukaemic cells through ROS production

Publication date: Available online 4 October 2014
Source:Phytochemistry

Author(s): Stefano Dall’Acqua , Maria Antonella Linardi , Roberta Bortolozzi , Maria Clauser , Sara Marzocchini , Filippo Maggi , Marcello Nicoletti , Gabbriella Innocenti , Giuseppe Basso , Giampietro Viola

Continuing our research on antiproliferative agents from plants, we extended our interest on further compounds isolated from Ferula communis and Ferulago campestris. One new daucane (DE-20) and one new phenol derivative (PH-3) were isolated and characterized in addition to six daucane, three coumarins and four simple phenolics. The cytotoxic activity was evaluated against a panel of six human tumor cell lines. The derivative DE-17 that resulted moderately active on all the studied cell lines was studied to evaluate its possible mechanism of action. DE-17 was able to induce apoptosis in a time and concentration-dependent manner in SEM and Jurkat cell lines. We observed that DE-17 just after 1h of treatment increased the reactive oxygen species (ROS) production and that the co-incubation of DE-17 with ROS scavengers significantly increased cell viability suggesting that ROS-mediated downstream signaling is essential for the antiproliferative effects of DE-17. At later times of incubation DE-17 induced mitochondrial depolarization, as well as caspase-3 and -9 activation suggesting that apoptosis follow the mitochondrial pathway. Concomitantly to ROS induction, a remarkable decrease of mRNA expression of several antioxidant enzymes and intracellular GSH content was detected in treated cells compared to controls further indicative of oxidative stress. Taken together our results showed for the first time that daucane esters induces apoptotic cell death through a ROS-mediated mechanism in human leukemia cells.

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Posted on 31 October 2014 | 3:46 am


Bioactive compounds from transformed root cultures and aerial parts of Bethencourtia hermosae

Publication date: Available online 6 October 2014
Source:Phytochemistry

Author(s): Braulio M. Fraga , Carmen E. Díaz , Leonardo J. Amador , Matías Reina , Omar Santana , Azucena González-Coloma

A chemical study of Bethencourtia hermosae, aerial parts and in vitro root cultures, transformed by Agrobacterium rhizogenes, afforded the hitherto unreported sesquiterpenes ceratopicanol angelate (1), 8?-hydroxy-african-4(5)-en-3-one tiglate (4), 8?-hydroxy-african-4(5)-en-3-one 3?-angeloxy-2?-methylbutanoate (5), 1?,8?-dihydroxy-african-4(5)-en-3-one 8?-angelate (7) and 6?,8?-dihydroxy-african-4(5)-en-3-one 8?-angelate (8). In addition, 8?-hydroxy-african-4(5)-en-3-one (6) was isolated for the first time from a natural source, along with the rare sesquiterpenoid senecrassidiol (10) and two jacaranone derivatives 14 and 16. Known pyrrolizidine alkaloids, together with previously unreported hermosine (23), have also been isolated from this plant. The insect antifeedant activities of the extracts and compounds were studied together with their cytotoxic effects against insect (Sf9) and mammalian (CHO) cell lines.

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Posted on 31 October 2014 | 3:46 am


Jatrophidin I, a cyclic peptide from Brazilian Jatropha curcas L.: Isolation, characterization, conformational studies and biological activity

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Wanessa F. Altei , Douglas G. Picchi , Barbara M. Abissi , Guilherme M. Giesel , Otavio Flausino Jr. , Michèle Reboud-Ravaux , Hugo Verli , Edson Crusca Jr. , Edilberto R. Silveira , Eduardo M. Cilli , Vanderlan S. Bolzani

A cyclic peptide, jatrophidin I, was isolated from the latex of Jatropha curcas L. Its structure was elucidated by extensive 2D NMR spectroscopic analysis, with additional conformational studies performed using Molecular Dynamics/Simulated Annealing (MD/SA). Jatrophidin I had moderate protease inhibition activity when compared with pepstatin A; however, the peptide was inactive in antimalarial, cytotoxic and antioxidant assays.

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Posted on 31 October 2014 | 3:46 am


Editorial Board/Publication Information

Publication date: October 2014
Source:Phytochemistry, Volume 106









Posted on 31 October 2014 | 3:46 am


Analyses of flooding tolerance of soybean varieties at emergence and varietal differences in their proteomes

Publication date: October 2014
Source:Phytochemistry, Volume 106

Author(s): Yohei Nanjo , Hee-Young Jang , Hong-Sig Kim , Susumu Hiraga , Sun-Hee Woo , Setsuko Komatsu

Flooding of fields due to heavy and/or continuous rainfall influences soybean production. To identify soybean varieties with flooding tolerance at the seedling emergence stage, 128 soybean varieties were evaluated using a flooding tolerance index, which is based on plant survival rates, the lack of apparent damage and lateral root development, and post-flooding radicle elongation rate. The soybean varieties were ranked according to their flooding tolerance index, and it was found that the tolerance levels of soybean varieties exhibit a continuum of differences between varieties. Subsequently, tolerant, moderately tolerant and sensitive varieties were selected and subjected to comparative proteomic analysis to clarify the tolerance mechanism. Proteomic analysis of the radicles, combined with correlation analysis, showed that the ratios of RNA binding/processing related proteins and flooding stress indicator proteins were significantly correlated with flooding tolerance index. The RNA binding/processing related proteins were positively correlated in untreated soybeans, whereas flooding stress indicator proteins were negatively correlated in flooded soybeans. These results suggest that flooding tolerance is regulated by mechanisms through multiple factors and is associated with abundance levels of the identified proteins.

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Posted on 31 October 2014 | 3:46 am


Saponins in the genus Panax L. (Araliaceae): A systematic review of their chemical diversity

Publication date: October 2014
Source:Phytochemistry, Volume 106

Author(s): Wen-zhi Yang , Ying Hu , Wan-ying Wu , Min Ye , De-an Guo

The Panax genus is a crucial source of natural medicines that has benefited human health for a long time. Three valuable medicinal herbs, namely Panax ginseng, Panax quinquefolius, and Panax notoginseng, have received considerable interest due to their extensive application in clinical therapy, healthcare products, and as foods and food additives world-wide. Panax species are known to contain abundant levels of saponins, also dubbed ginsenosides, which refer to a series of dammarane or oleanane type triterpenoid glycosides. These saponins exhibit modulatory effects to the central nervous system and beneficial effects to patients suffering from cardiovascular diseases, and also have anti-diabetic and anti-tumor properties. To the end of 2012, at least 289 saponins were reported from eleven different Panax species. This comprehensive review describes the advances in the phytochemistry of the genus Panax for the period 1963–2012, based on the 134 cited references. The reported saponins can be classified into protopanaxadiol, protopanaxatriol, octillol, oleanolic acid, C17 side-chain varied, and miscellaneous subtypes, according to structural differences in sapogenins. The investigational history of Panax is also reviewed, with special attention being paid to the structural features of the six different subtypes, together with their 1H and 13C NMR spectroscopic characteristics which are useful for determining their structures and absolute configuration.

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Posted on 31 October 2014 | 3:46 am


Cytisine-like alkaloids from Ormosia hosiei Hemsl. & E.H. Wilson

Publication date: November 2014
Source:Phytochemistry, Volume 107

Author(s): Isabelle Pouny , Muriel Batut , Laure Vendier , Bruno David , Sirong Yi , François Sautel , Paola B. Arimondo , Georges Massiot

Four alkaloids named hosieines A–D were isolated from the root and stem of Ormosia hosiei. Their flat structures were established by mass spectrometry and by a combination of NMR experiments. These molecules probably share a common biosynthetic origin with the lupin alkaloids but they differ in the formation of the last ring, being here part of a rare 2-azabicyclo[3.2.1]octane system. Their absolute configuration was determined by X-ray crystallography using CuK? radiation. As has been described for cytisine, they display a remarkable affinity towards neuronal nicotinic acetylcholine ?4?2 receptor.

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Posted on 31 October 2014 | 3:46 am


Investigation of a substrate-specifying residue within Papaver somniferum and Catharanthus roseus aromatic amino acid decarboxylases

Publication date: October 2014
Source:Phytochemistry, Volume 106

Author(s): Michael P. Torrens-Spence , Michael Lazear , Renee von Guggenberg , Haizhen Ding , Jianyong Li

Plant aromatic amino acid decarboxylases (AAADs) catalyze the decarboxylation of aromatic amino acids with either benzene or indole rings. Because the substrate selectivity of AAADs is intimately related to their physiological functions, primary sequence data and their differentiation could provide significant physiological insights. However, due to general high sequence identity, plant AAAD substrate specificities have been difficult to identify through primary sequence comparison. In this study, bioinformatic approaches were utilized to identify several active site residues within plant AAAD enzymes that may impact substrate specificity. Next a Papaver somniferum tyrosine decarboxylase (TyDC) was selected as a model to verify our putative substrate-dictating residues through mutation. Results indicated that mutagenesis of serine 372 to glycine enables the P. somniferum TyDC to use 5-hydroxytryptophan as a substrate, and reduces the enzyme activity toward 3,4-dihydroxy-L-phenylalanine (dopa). Additionally, the reverse mutation in a Catharanthus roseus tryptophan decarboxylase (TDC) enables the mutant enzyme to utilize tyrosine and dopa as substrates with a reduced affinity toward tryptophan. Molecular modeling and molecular docking of the P. somniferum TyDC and the C. roseus TDC enzymes provided a structural basis to explain alterations in substrate specificity. Identification of an active site residue that impacts substrate selectivity produces a primary sequence identifier that may help differentiate the indolic and phenolic substrate specificities of individual plant AAADs.

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Posted on 31 October 2014 | 3:46 am





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