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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:



Announcement for the Phytochemical Society of Europe (PSE)

Publication date: August 2014
Source:Phytochemistry, Volume 104









Posted on 21 July 2014 | 6:25 pm


Volatile compounds in cryptic species of the Aneura pinguis complex and Aneura maxima (Marchantiophyta, Metzgeriidae)

Publication date: Available online 14 July 2014
Source:Phytochemistry

Author(s): Rafa? Wawrzyniak , Wies?aw Wasiak , Alina B?czkiewicz , Katarzyna Buczkowska

Aneura pinguis is one of the liverwort species complexes that consist of several cryptic species. Ten samples collected from different regions in Poland are in the focus of our research. Eight of the A. pinguis complex belonging to four cryptic species (A, B, C, E) and two samples of closely related species Aneura maxima were tested for the composition of volatile compounds. The HS-SPME technique coupled to GC/FID and GC/MS analysis has been applied. The fiber coated with DVB/CAR/PDMS has been used. The results of the present study, revealed the qualitative and quantitative differences in the composition of the volatile compounds between the studied species. Mainly they are from the group of sesquiterpenoids, oxygenated sesquiterpenoids and aliphatic hydrocarbons. The statistical methods (CA and PCA) showed that detected volatile compounds allow to distinguish cryptic species of A. pinguis. All examined cryptic species of the A. pinguis complex differ from A. maxima. Species A and E of A. pinguis, in CA and PCA, form separate clusters remote from two remaining cryptic species of A. pinguis (B and C) and A. maxima. Relationship between the cryptic species appeared from the chemical studies are in accordance with that revealed on the basis of DNA sequences.

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Posted on 21 July 2014 | 6:25 pm


Stable, water extractable isothiocyanates from Moringa oleifera leaves attenuate inflammation in vitro

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Carrie Waterman , Diana M. Cheng , Patricio Rojas-Silva , Alexander Poulev , Julia Dreifus , Mary Ann Lila , Ilya Raskin

Moringa (Moringa oleifera Lam.) is an edible plant used as both a food and medicine throughout the tropics. A moringa concentrate (MC), made by extracting fresh leaves with water, utilized naturally occurring myrosinase to convert four moringa glucosinolates into moringa isothiocyanates. Optimum conditions maximizing MC yield, 4-[(?-L-rhamnosyloxy)benzyl]isothiocyanate, and 4-[(4?-O-acetyl-?-L-rhamnosyloxy)benzyl]isothiocyanate content were established (1:5 fresh leaf weight to water ratio at room temperature). The optimized MC contained 1.66% isothiocyanates and 3.82% total polyphenols. 4-[(4?-O-acetyl-?-L-rhamnosyloxy)benzyl]isothiocyanate exhibited 80% stability at 37°C for 30days. MC, and both of the isothiocyanates described above significantly decreased gene expression and production of inflammatory markers in RAW macrophages. Specifically, both attenuated expression of iNOS and IL-1? and production of nitric oxide and TNF? at 1 and 5?M. These results suggest a potential for stable and concentrated moringa isothiocyanates, delivered in MC as a food-grade product, to alleviate low-grade inflammation associated with chronic diseases.

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Highlights

Fresh leaf concentrate of Moringa oleifera (MC) utilized in situ for bioconversion of glucosinolates (14) to chemically stable isothiocyanates (58). MC significantly reduced inflammatory biomarkers in macrophages.





Posted on 21 July 2014 | 6:25 pm


What the devil is in your phytomedicine? Exploring species substitution in Harpagophytum through chemometric modeling of 1H-NMR and UHPLC-MS datasets

Publication date: Available online 17 July 2014
Source:Phytochemistry

Author(s): Nontobeko P. Mncwangi , Alvaro M. Viljoen , Jianping Zhao , Ilze Vermaak , Wei Chen , Ikhlas Khan

Harpagophytum procumbens (Pedaliaceae) and its close taxonomical ally Harpagophytum zeyheri, indigenous to southern Africa, are being harvested for exportation to Europe where phytomedicines are developed to treat inflammation-related disorders. The phytochemical variation within and between natural populations of H. procumbens (n =241) and H. zeyheri (n =107) was explored using proton nuclear magnetic resonance (1H-NMR) and ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) in combination with multivariate data analysis methods. The UHPLC-MS results revealed significant variation in the harpagoside content: H. procumbens (0.17–4.37%); H. zeyheri (0.00–3.07%). Only 41% of the H. procumbens samples and 17% of the H. zeyheri samples met the pharmacopoeial specification of ?1.2%. Both principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) indicated separation based on species (UHPLC-MS data OPLS-DA model statistics: R 2X=0.258, R 2Y (cum)=0.957 and Q 2(cum)=0.934; 1H-NMR data OPLS-DA model statistics: R 2X=0.830, R 2Y=0.865 (cum) and Q 2(cum)=0.829). It was concluded that two species are not chemically equivalent and should not be used interchangeably.

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Posted on 21 July 2014 | 6:25 pm


Graphical Contents List

Publication date: August 2014
Source:Phytochemistry, Volume 104









Posted on 21 July 2014 | 6:25 pm


Quinoid glycosides from Forsythia suspensa

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Chang Li , Yi Dai , Shu-Xiang Zhang , Ying-Hui Duan , Ming-Li Liu , Liu-Yuan Chen , Xin-Sheng Yao

Phytochemical investigation on Forsythia suspensa (Thunb.) Vahl afforded 10 compounds, including quinoid glycosides, lignan glycosides, phenylethanoid glycoside and allylbenzene glycoside together with 13 known ones. Their structures were established based on extensive spectroscopic data analyses, including IR, UV, HRESIMS, 1D NMR and 2D NMR. Absolute configurations were determined by ECD calculation method and chemical degradation. In addition, all compounds were evaluated for their antiviral activity against influenza A (H1N1) virus and several were further evaluated against respiratory syncytial virus (RSV) in vitro. Among them, two previously known compounds showed significant activities against RSV with EC50 values of 3.43 and 6.72?M.

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Posted on 21 July 2014 | 6:25 pm


Comparative plant sphingolipidomic reveals specific lipids in seeds and oil

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Frédérique Tellier , Alessandra Maia-Grondard , Isabelle Schmitz-Afonso , Jean-Denis Faure

Plant sphingolipids are a highly diverse family of structural and signal lipids. Owing to their chemical diversity and complexity, a powerful analytical method was required to identify and quantify a large number of individual molecules with a high degree of structural accuracy. By using ultra-performance liquid chromatography with a single elution system coupled to electrospray ionization tandem mass spectrometry (UPLC–ESI-MS/MS) in the positive multiple reaction monitoring (MRM) mode, detailed sphingolipid composition was analyzed in various tissues of two Brassicaceae species Arabidopsis thaliana and Camelina sativa. A total of 300 molecular species were identified defining nine classes of sphingolipids, including Cers, hCers, Glcs and GIPCs. High-resolution mass spectrometry identified sphingolipids including amino- and N-acylated-GIPCs. The comparative analysis of seedling, seed and oil sphingolipids showed tissue specific distribution suggesting metabolic channeling and compartmentalization

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Posted on 21 July 2014 | 6:25 pm


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

Publication date: Available online 19 July 2014
Source:Phytochemistry

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 21 July 2014 | 6:25 pm


A chitinolytic endochitinase and ?-N-acetylglucosaminidase-based system from Hevea latex in generating N-acetylglucosamine from chitin

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Pannawich Sukprasirt , Rapepun Wititsuwannakul

An endochitinase and ?-N-acetylglucosaminidase (NAGase) were purified and characterised from fresh rubber latex serum. These enzymes were used in a total enzyme-based system to produce pure N-acetylglucosamine (NAG) from chitin. The N-terminal amino acid sequences of both purified endochitinase (KEESRRRRHR) and NAGase (AAVDSDTLEI) lacked homology with other known chitinases, including hevamine from rubber latex lutoids. The apparent kinetic parameters, K m and V max, for the endochitinase using 4-MU-?-(NAG)3 as a substrate were 99.73?M and 29.49pkatmg?1, respectively. For NAGase, using 4-MU-?-NAG as a substrate, the corresponding K m and V max values were 20.4?M and 25.82pkatmg?1. When an enzyme incubation mixture containing a 1:1 (pkat/pkat) activity mixed ratio of endochitinase: NAGase was employed, the maximum yield of N-acetylglucosamine (NAG) obtained was 98% from ?-chitin and 20% from ?-chitin. These yields were obtained after 4days of hydrolysis of equal amounts of ?-chitin and ?-chitin in the mixture. Thus, ?-chitin was the preferred substrate compared to ?-chitin by a ratio of nearly five to one. Mass spectroscopic analysis, using electrospray ionisation mass spectrometry (ESI-MS), of the product obtained from ?-chitin after digestion (for 24h) depicted one distinct major molecular ion peak m/z 260.1, a small minor ion peak m/z 481.2, a potassium adduct of NAG and a potassium adduct of two NAG molecules. Furthermore, experiments to establish the commercial production of NAG using crude enzymes of Hevea latex serum are currently in progress.

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Posted on 21 July 2014 | 6:25 pm


Indolosesquiterpene alkaloids from the Cameroonian medicinal plant Polyalthia oliveri (Annonaceae)

Publication date: Available online 16 July 2014
Source:Phytochemistry

Author(s): Simeon Fogue Kouam , Alain Wembe Ngouonpe , Marc Lamshöft , Ferdinand Mouafo Talontsi , Jonathan O. Bauer , Carsten Strohmann , Bonaventure Tchaleu Ngadjui , Hartmut Laatsch , Michael Spiteller

The stem bark of Polyalthia oliveri was screened for its chemical constituents using liquid chromatography high resolution mass spectrometry resulting in the isolation of three indolosesquiterpene alkaloids named 8?-polyveolinone (1), N-acetyl-8?-polyveolinone (2) and N-acetyl-polyveoline (3), together with three known compounds, dehydro-O-methylisopiline (4), N-methylurabaine (5) and polycarpol (6). The structures of the compounds were elucidated by means of high resolution mass spectrometry and different NMR techniques and chemical transformations. Their absolute configurations were assigned by ab-initio calculation of CD and ORD data (for 2 and 3) and X-ray diffraction analysis (for 2). Compounds 2 and 3 exhibited moderate antiplasmodial activity against erythrocytic stages of chloroquine-sensitive Plasmodium falciparum NF54 strain and low cytotoxicity on rat skeletal myoblast (L6) cell line.

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Posted on 21 July 2014 | 6:25 pm


Expression of terpene synthase genes associated with the formation of volatiles in different organs of Vitis vinifera

Publication date: Available online 7 July 2014
Source:Phytochemistry

Author(s): Fabiola Matarese , Angela Cuzzola , Giancarlo Scalabrelli , Claudio D’Onofrio

Plants produce a plethora of volatile organic compounds (VOCs) which are important in determining the quality and nutraceutical properties of horticultural food products, including the taste and aroma of wine. Given that some of the most prevalent grape aroma constituents are terpenoids, we investigated the possible variations in the relative expression of terpene synthase (TPS) genes that depend on the organ. We thus analysed mature leaves, young leaves, stems, young stems, roots, rachis, tendrils, peduncles, bud flowers, flowers and berries of cv Moscato bianco in terms of their VOC content and the expression of 23 TPS genes. In terms of the volatile characterization of the organs by SPME/GC–MS analysis, flower buds and open flowers appeared to be clearly distinct from all the other organs analysed in terms of their high VOC concentration. Qualitatively detected VOCs clearly separated all the vegetative organs from flowers and berries, then the roots and rachis from other vegetative organs and flowers from berries, which confirms the specialization in volatile production among different organs. Our real-time RT-PCR results revealed that the majority of TPS genes analysed exhibited detectable transcripts in all the organs investigated, while only some were found to be expressed specifically in one or just a few organs. In most cases, we found that the known products of the in vitro assay of VvTPS enzymes corresponded well to the terpenes found in the organs in which the encoding gene was expressed, as in the case of (E)-?-caryophyllene synthases, ?-terpineol synthase and ?-farnesene synthase. In addition, we found groups of homologous TPS genes, such as (E)-?-caryophyllene and ?-ocimene synthases, expressed distinctively in the various tissues. This thus confirmed the subfunctionalization events and a specialization on the basis of the organs in which they are mostly expressed.

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Posted on 21 July 2014 | 6:25 pm


Expression of a fungal glucuronoyl esterase in Populus: Effects on wood properties and saccharification efficiency

Publication date: Available online 2 July 2014
Source:Phytochemistry

Author(s): Madhavi Latha Gandla , Marta Derba-Maceluch , Xiaokun Liu , Lorenz Gerber , Emma R. Master , Ewa J. Mellerowicz , Leif J. Jönsson

The secondary walls of angiosperms contain large amounts of glucuronoxylan that is thought to be covalently linked to lignin via ester bonds between 4-O-methyl-?-d-glucuronic acid (4-O-Me-GlcA) moieties in glucuronoxylan and alcohol groups in lignin. This linkage is proposed to be hydrolysed by glucuronoyl esterases (GCEs) secreted by wood-degrading fungi. We report effects of overexpression of a GCE from the white-rot basidiomycete Phanerochaete carnosa, PcGCE, in hybrid aspen (Populus tremula L. x tremuloides Michx.) on the wood composition and the saccharification efficiency. The recombinant enzyme, which was targeted to the plant cell wall using the signal peptide from hybrid aspen cellulase PttCel9B3, was constitutively expressed resulting in the appearance of GCE activity in protein extracts from developing wood. Diffuse reflectance FT-IR spectroscopy and pyrolysis–GC/MS analyses showed significant alternation in wood chemistry of transgenic plants including an increase in lignin content and S/G ratio, and a decrease in carbohydrate content. Sequential wood extractions confirmed a massive (+43%) increase of Klason lignin, which was accompanied by a ca. 5% decrease in cellulose, and ca. 20% decrease in wood extractives. Analysis of the monosaccharide composition using methanolysis showed a reduction of 4-O-Me-GlcA content without a change in Xyl contents in transgenic lines, suggesting that the covalent links between 4-O-Me-GlcA moieties and lignin protect these moieties from degradation. Enzymatic saccharification without pretreatment resulted in significant decreases of the yields of Gal, Glc, Xyl and Man in transgenic lines, consistent with their increased recalcitrance caused by the increased lignin content. In contrast, the enzymatic saccharification after acid pretreatment resulted in Glc yields similar to wild-type despite of their lower cellulose content. These data indicate that whereas PcGCE expression in hybrid aspen increases lignin deposition, the inhibitory effects of lignin are efficiently removed during acid pretreatment, and the extent of wood cellulose conversion during hydrolysis after acid pretreatment is improved in the transgenic lines possible due to reduced cell wall cross-links between cell wall biopolymers by PcGCE.

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Posted on 21 July 2014 | 6:25 pm


Two types of alcohol dehydrogenase from Perilla can form citral and perillaldehyde

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Naoko Sato-Masumoto , Michiho Ito

Studies on the biosynthesis of oil compounds in Perilla will help in understanding regulatory systems of secondary metabolites and in elucidating reaction mechanisms for natural product synthesis. In this study, two types of alcohol dehydrogenases, an aldo–keto reductase (AKR) and a geraniol dehydrogenase (GeDH), which are thought to participate in the biosynthesis of perilla essential oil components, such as citral and perillaldehyde, were isolated from three pure lines of perilla. These enzymes shared high amino acid sequence identity within the genus Perilla, and were expressed regardless of oil type. The overall reaction from geranyl diphosphate to citral was performed in vitro using geraniol synthase and GeDH to form a large proportion of citral and relatively little geraniol as reaction products. The biosynthetic pathway from geranyl diphosphate to citral, the main compound of citral-type perilla essential oil, was established in this study.

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Posted on 21 July 2014 | 6:25 pm


Isochromenones, isobenzofuranone, and tetrahydronaphthalenes produced by Paraphoma radicina, a fungus isolated from a freshwater habitat

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Tamam El-Elimat , Huzefa A. Raja , Mario Figueroa , Joseph O. Falkinham III , Nicholas H. Oberlies

Six isochromenones (16), clearanols F (5) and G (6), one isobenzofuranone (7), and two tetrahydronaphthalene derivatives (8 and radinaphthalenone (9)), were isolated and identified from a culture of the fungus Paraphoma radicina, which was isolated from submerged wood in a freshwater lake. Compounds 5, 6 and 9 were previously unknown. The structures were elucidated using a set of spectroscopic and spectrometric techniques; the absolute configurations of compounds 5 and 6 were determined by comparison of their experimental ECD measurements with values predicted by TDDFT calculations. Compounds 19 were evaluated for antimicrobial activity against an array of bacteria and fungi. The inhibitory activity of compound 4 against Staphylococcus aureus biofilm formation was evaluated.

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Posted on 21 July 2014 | 6:25 pm


Biochemical characterization of the castor bean ent-kaurene synthase(-like) family supports quantum chemical view of diterpene cyclization

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Alana J. Jackson , David M. Hershey , Taylor Chesnut , Meimei Xu , Reuben J. Peters

It has become apparent that plants have extensively diversified their arsenal of labdane-related diterpenoids (LRDs), in part via gene duplication and neo-functionalization of the ancestral ent-kaurene synthase (KS) required for gibberellin metabolism. For example, castor bean (Ricinus communis) was previously shown to produce an interesting set of biosynthetically related diterpenes, specifically ent-sandracopimaradiene, ent-beyerene, and ent-trachylobane, in addition to ent-kaurene, using four separate diterpene synthases, albeit these remain unidentified. Notably, despite mechanistic similarity of the underlying reaction to that catalyzed by KSs, ent-beyerene and ent-trachylobane synthases have not yet been identified. Given our interest in LRD biosynthesis, and the recent availability of the castor bean genome sequence, a synthetic biology approach was applied to biochemically characterize the four KS(-like) enzymes [KS(L)s] found in Ricinus communis [i.e., the RcKS(L)s]. In particular, using bacteria engineered to produce the relevant ent-copalyl diphosphate precursor and synthetic genes based on the predicted RcKS(L)s, although this ultimately required correction of a “splicing” error in one of the predicted genes, highlighting the dependence of such a synthetic biology approach on accurate gene sequences. Nevertheless, it is possible to assign each of the four RcKS(L)s to one of the previously observed diterpene synthase activities, providing access to functionally enzymes. Intriguingly, the product distribution of the RcKS(L)s seems to support the distinct diterpene synthase reaction mechanism proposed by quantum chemical calculations, rather than the classically proposed pathway.

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Posted on 21 July 2014 | 6:25 pm


Glucosinolate profile and distribution among plant tissues and phenological stages of field-grown horseradish

Publication date: Available online 21 July 2014
Source:Phytochemistry

Author(s): Rosa Agneta , Filomena Lelario , Susanna De Maria , Christian Möllers , Sabino Aurelio Bufo , Anna Rita Rivelli

Profile and distribution of glucosinolates (GLS) were detected in plant tissues of horseradish at different developmental stages: beginning of vegetative re-growth, flowering and silique formation. The GLS profile varied widely in the different tissues: we identified 17 GLS in roots and sprouts, one of which was not previously characterized in horseradish, i.e. the 2(S)-hydroxy-2-phenylethyl-GLS (glucobarbarin) and/or 2(R)-hydroxy-2-phenylethyl-GLS (epiglucobarbarin), 11 already found in the roots, including the putative 2-methylsulfonyl-oxo-ethyl-GLS, and 5 previously recognized only in the sprouts. Fifteen of those GLS were also identified in young and cauline leaves, 12 in the mature leaves and 13 in the inflorescences. No difference in GLS profile was observed in plant among the phenological stages. Differences in concentrations of GLS, quantified as desulfated, were found in plant. At the beginning of vegetative re-growth, sprouts while showing the same profile of the roots were much richer in GLS having the highest total GLS concentrations (117.5 and 7.7?molg?1 dry weight in sprouts and roots, respectively). During flowering and silique forming stages, the roots still maintained lower amount of total GLS (7.4?molg?1 of dry weight, on average) with respect to the epigeous tissues, in which mature and young leaves showed the highest total concentrations (70.5 and 73.8?molg?1 of dry weight on average, respectively). Regardless of the phenological stages, the aliphatic GLS were always predominant in all tissues (95%) followed by indolic (2.6%) and benzenic (2.4%) GLS. Sinigrin contributed more than 90% of the total GLS concentration. Aliphatic GLS concentrations were much higher in the epigeous tissues, particularly in the mature and young leaves, while benzenic and indolic GLS concentrations were higher in the roots. Through the phenological stages, GLS concentration increased in young and mature leaves and decreased in cauline leaves and inflorescences, while it remained constant over time in roots.

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Highlights

Identification and quantification of glucosinolates (GLS) were performed in plant tissues during different developmental stages of horseradish (Armoracia rusticana). Overall, 17 GLS were identified, some tentatively assigned, one of which (glucobarbarin and/or epiglucobarbarin) was not previously reported in horseradish plant.





Posted on 21 July 2014 | 6:25 pm


Blue light-promoted rice leaf bending and unrolling are due to up-regulated brassinosteroid biosynthesis genes accompanied by accumulation of castasterone

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Masashi Asahina , Yuji Tamaki , Tomoaki Sakamoto , Kyomi Shibata , Takahito Nomura , Takao Yokota

In this study the relationship between blue light- and brassinosteroid-enhanced leaf lamina bending and unrolling in rice was investigated. Twenty-four hours (h) irradiation with white or blue light increased endogenous brassinosteroid levels, especially those of typhasterol and castasterone, in aerial tissues of rice seedlings. There was an accompanying up-regulation of transcript levels of CYP85A1/OsDWARF, encoding an enzyme catalyzing C-6 oxidation, after 6h under either white or blue light. These effects were not observed in seedlings placed under far-red or red light regimes. It was concluded that blue light up-regulates the levels of several cytochrome P450 enzymes including CYP85A1, thereby promoting the synthesis of castasterone, a biologically active brassinosteroid in rice. Based on these findings, it is considered that blue light-mediated rice leaf bending and unrolling are consequences of the enhanced biosynthesis of endogenous castasterone. In contrast to aerial tissues, brassinosteroid synthesis in roots appeared to be negatively regulated by white, blue and red light but positively controlled by far-red light.

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Posted on 21 July 2014 | 6:25 pm


Pregnane-type steroidal glycosides from Gymnema griffithii Craib.

Publication date: Available online 19 July 2014
Source:Phytochemistry

Author(s): Suphongphan Srisurichan , Songchan Puthong , Surachai Pornpakakul

Eight pregnane-type steroidal glycosides substituted with ortho-acetate groups were isolated from the methanolic extract of the pericarp of Gymnema griffithii fruits, and named gymnemogriffithosides A–H. Their structures were determined by spectroscopic analysis (one and two dimensional nuclear magnetic resonance, high resolution electrospray ionization mass spectrometry and attenuated total reflectance-Fourier transformed infrared spectroscopy), while the absolute structure of the steroidal skeleton of one of these was additionally determined using Mosher’s method. All compounds were evaluated for their in vitro (i) cytotoxic effects against five human tumor cell lines (BT 474, Chago, Hep-G2, KATO-III and SW620) and (ii) ?-glucosidase inhibitory activity.

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Posted on 21 July 2014 | 6:25 pm


Avenaol, a germination stimulant for root parasitic plants from Avena strigosa

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Hyun Il Kim , Takaya Kisugi , Pichit Khetkam , Xiaonan Xie , Kaori Yoneyama , Kenichi Uchida , Takao Yokota , Takahito Nomura , Christopher S.P. McErlean , Koichi Yoneyama

Root exudates from the allelopathic plant, black oat (Avena strigosa Schreb.), were found to contain at least six different germination stimulants for root parasitic plants, but no known strigolactones (SLs). One of these germination stimulants was purified and named avenaol. Its HR–ESI–TOFMS analysis indicated that the molecular formula of avenaol is C20H24O7, and thus it contains an additional carbon compared with known C19-SLs. Its structure was determined as 5-((E)-(5-(3-hydroxy-1,5,5-trimethyl-2-oxobicyclo[4.1.0]heptan-7-yl)-2-oxodihydrofuran-3(2H)-ylidene)methoxy)-3-methylfuran-2(5H)-one, by 1D and 2D NMR spectroscopy, and ESI- and EI-MS spectrometry. Although avenaol contains the C–D moiety, the common structural feature for all known SLs, it lacks the B ring and has an additional carbon atom between the A and C rings. Avenaol is a potent germination stimulant of Phelipanche ramosa seeds, but only a weak stimulant for seeds of Striga hermonthica and Orobanche minor.

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Posted on 21 July 2014 | 6:25 pm


Age-dependent changes from allylphenol to prenylated benzoic acid production in Piper gaudichaudianum Kunth

Publication date: Available online 17 July 2014
Source:Phytochemistry

Author(s): Anderson M. Gaia , Lydia F. Yamaguchi , Christopher S. Jeffrey , Massuo J. Kato

HPLC-DAD and principal component analysis (PCA) of the 1H NMR spectrum of crude plant extracts showed high chemical variability among seedlings and adult organs of Piper gaudichaudianum. While gaudichaudianic acid was the major compound in the adult leaves, apiole and dillapiole were the major compounds in their seedling leaves. By the 15th month of seedling growth, the levels of apiole and dillapiole decreased and gaudichaudianic acid appeared along with two compounds, biosynthetically related to gaudichaudianic acid.

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Posted on 21 July 2014 | 6:25 pm


Characterization of an uncharacterized aldo-keto reductase gene from peach and its role in abiotic stress tolerance

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Yoshinori Kanayama , Ryosuke Mizutani , Shino Yaguchi , Ayano Hojo , Hiroki Ikeda , Manabu Nishiyama , Koki Kanahama

The aldo-keto reductase (AKR) superfamily is a large enzyme group of NADP-dependent oxidoreductases with numerous roles in metabolism, but many members in this superfamily remain uncharacterized. Here, PpAKR1, which was cloned from the rosaceous peach tree (Prunus persica), was investigated as a member of the superfamily. While PpAKR1 had amino acids that are important in AKRs and which belonged to the AKR4 group, PpAKR1 did not seem to belong to any of the AKR4 subgroups. PpAKR1 mRNA abundance increased with abscisic acid, oxidative stress, and cold and salt stress treatments in peach. NADP-dependent polyol dehydrogenase activity was increased in Arabidopsis thaliana transformed with PpAKR1. Salt tolerance increased in Arabidopsis transformed with PpAKR1. PpAKR1, which was a previously uncharacterized member of the AKR superfamily, could be involved in the abiotic stress tolerance.

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Posted on 21 July 2014 | 6:25 pm


Dimeric guaianolides from Artemisia absinthium

Publication date: Available online 15 July 2014
Source:Phytochemistry

Author(s): Ablajan Turak , She-Po Shi , Yong Jiang , Peng-Fei Tu

Five dimeric guaianolides, absinthins A–E, and seven known dimeric guaianolides were isolated from Artemisia absinthium. Their structures were elucidated based on 1D- and 2D-NMR experiments, including 1H NMR, 13C NMR, DEPT, 1H–1H COSY, HSQC, HMBC, and NOESY, and through HRESIMS data analysis. The absolute configuration of the known compound, anabsinthin, was determined by X-ray crystallographic analysis. The isolated compounds were tested to assess their inhibitory activities on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 cells; absinthin C and isoanabsinthin exhibited significant inhibitory effects with IC50 values of 1.52 and 1.98?M, respectively.

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Posted on 21 July 2014 | 6:25 pm


Editorial Board/Publication Information

Publication date: August 2014
Source:Phytochemistry, Volume 104









Posted on 21 July 2014 | 6:25 pm


Asphodosides A-E, anti-MRSA metabolites from Asphodelus microcarpus

Publication date: Available online 14 July 2014
Source:Phytochemistry

Author(s): Mohammed M. Ghoneim , Khaled M. Elokely , Atef A. El-Hela , Abd-Elsalam I. Mohammad , Melissa Jacob , Mohamed M. Radwan , Robert J. Doerksen , Stephen J. Cutler , Samir A. Ross

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm. et Viv. (Xanthorrhoeaceae or Asphodelaceae) resulted in isolation of five compounds identified as asphodosides A-E (15). Compounds 24 showed activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 1.62, 7.0 and 9.0?g/mL, respectively. They also exhibited activity against Staphylococcus aureus (non-MRSA) with IC50 values of 1.0, 3.4 and 2.2?g/mL, respectively. The structure elucidation of isolated metabolites was carried out using spectroscopic data (1D and 2D NMR), optical rotation and both experimental and calculated electronic circular dichroism (ECD).

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Posted on 21 July 2014 | 6:25 pm


Structural alteration of cell wall pectins accompanies pea development in response to cold

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Laëtitia Baldwin , Jean-Marc Domon , John F. Klimek , Françoise Fournet , Hélène Sellier , Françoise Gillet , Jérôme Pelloux , Isabelle Lejeune-Hénaut , Nicholas C. Carpita , Catherine Rayon

Pea (Pisum sativum) cell wall metabolism in response to chilling was investigated in a frost-sensitive genotype ‘Terese’ and a frost-tolerant genotype ‘Champagne’. Cell walls isolated from stipules of cold acclimated and non-acclimated plants showed that cold temperatures induce changes in polymers containing xylose, arabinose, galactose and galacturonic acid residues. In the tolerant cultivar Champagne, acclimation is accompanied by increases in homogalacturonan, xylogalacturonan and highly branched Rhamnogalacturonan I with branched and unbranched (1?5)-?-arabinans and (1?4)-?-galactans. In contrast, the sensitive cultivar Terese accumulates substantial amounts of (1?4)-?-xylans and glucuronoxylan, but not the pectins. Greater JIM7 labeling was observed in Champagne compared to Terese, indicating that cold acclimation also induces an increase in the degree of methylesterification of pectins. Significant decrease in polygalacturonase activities in both genotypes were observed at the end of cold acclimation. These data indicate a role for esterified pectins in cold tolerance. The possible functions for pectins and their associated arabinans and galactans in cold acclimation are discussed.

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Posted on 21 July 2014 | 6:25 pm


Roles of apoplastic peroxidases in plant response to wounding

Publication date: Available online 12 July 2014
Source:Phytochemistry

Author(s): Farida Minibayeva , Richard Peter Beckett , Ilse Kranner

Apoplastic class III peroxidases (EC 1.11.1.7) play key roles in the response of plants to pathogen infection and abiotic stresses, including wounding. Wounding is a common stress for plants that can be caused by insect or animal grazing or trampling, or result from agricultural practices. Typically, mechanical damage to a plant immediately induces a rapid release and activation of apoplastic peroxidases, and an oxidative burst of reactive oxygen species (ROS), followed by the upregulation of peroxidase genes. We discuss how plants control the expression of peroxidases genes upon wounding, and also the sparse information on peroxidase-mediated signal transduction pathways. Evidence reviewed here suggests that in many plants production of the ROS that comprise the initial oxidative burst results from a complex interplay of peroxidases with other apoplastic enzymes. Later responses following wounding include various forms of tissue healing, for example through peroxidase-dependent suberinization, or cell death. Limited data suggest that ROS-mediated death signalling during the wound response may involve the peroxidase network, together with other redox molecules. In conclusion, the ability of peroxidases to both generate and scavenge ROS plays a key role in the involvement of these enigmatic enzymes in plant stress tolerance.

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Highlights

The ability of apoplastic peroxidases to generate or scavenge ROS is a key element of wound response, wound healing and cell death in plants.





Posted on 21 July 2014 | 6:25 pm


Cadinane sesquiterpenoids from the basidiomycete Stereum cf. sanguinolentum BCC 22926

Publication date: Available online 5 July 2014
Source:Phytochemistry

Author(s): Taridaporn Bunyapaiboonsri , Seangaroon Yoiprommarat , Rujirek Nopgason , Somjit Komwijit , Sukitaya Veeranondha , Pucharapa Puyngain , Thitiya Boonpratuang

Stereumins Q–U, together with known stereumins A, B, K, L, and N, as well as ent-strobilols E and G were isolated from the culture of Stereum cf. sanguinolentum BCC 22926. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of stereumins A and Q, as well as ent-strobilol E were established by application of the modified Mosher’s method. Stereumin T displayed antibacterial activity against Bacillus cereus with a MIC value of 3.97?M.

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Highlights

Stereumins Q–U were isolated from the liquid culture of Stereum cf. sanguinolentum BCC 22926. Stereumin T displayed antibacterial activity against Bacillus cereus with a MIC value of 3.97?M.





Posted on 21 July 2014 | 6:25 pm


Elaeodendron orientale as a source of cytotoxic cardenolides

Publication date: Available online 7 July 2014
Source:Phytochemistry

Author(s): Alex A. Osorio , Manuel R. López , Ignacio A. Jiménez , Laila M. Moujir , Matías L. Rodríguez , Isabel L. Bazzocchi

In the present study, we report six cardiac glycosides (16) along with four known ones (710) isolated from the leaves and fruits of Elaeodendron orientale. Their stereostructures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR, and the absolute configuration of 1 was determined by X-ray diffraction analysis. The compounds were evaluated for growth inhibitory activity against a panel of human cancer cell lines, HeLa, A-549, MCF-7 and HL-60, and normal Vero cells. Four compounds from this series (5 and 79, IC50 values ranging from 0.01 to 0.07?M) exhibited cytotoxicity against three of the cancer cell lines assayed that was similar to or higher than the well-known therapies digoxin and digitoxigenin. Taking into account the narrow safety range of cardiac glycosides used in clinic, this series shows a selectivity index higher than 3 for three of the cancer cell lines assayed, increasing their interest for further study.

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Posted on 21 July 2014 | 6:25 pm


Lysophosphatidylcholine enhances susceptibility in signaling pathway against pathogen infection through biphasic production of reactive oxygen species and ethylene in tobacco plants

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Soo Jin Wi , So yeon Seo , Kyoungwon Cho , Myung Hee Nam , Ky Young Park

It was previously reported that the amounts of lysophosphatidylcholines (lysoPCs), which are naturally occurring bioactive lipid molecules, significantly increase following pathogen inoculation, as determined using ultraperformance liquid chromatography–quadrupole-time of flight/mass spectrometry analyses. Here, real-time quantitative RT-PCR was performed for the phospholipase A2 (PLA2) genes, Nt1PLA2 and Nt2PLA2 , which are responsible for LysoPCs generation. The transcription level of Nt2PLA2 in pathogen-infected tobacco plants transiently peaked at 1h and 36h, whereas induction of Nt1PLA2 transcription peaked at 36h. A prominent biphasic ROS accumulation in lysoPC (C18:1(9Z))-treated tobacco leaves was also observed. Transcription of NtRbohD, a gene member of NADPH oxidase, showed biphasic kinetics upon lysoPC 18:1 treatment, as evidenced by an early transient peak in phase I at 1h and a massive peak in phase II at 12h. Each increase in NtACS2 and NtACS4 transcription, gene members of the ACC synthase family, was followed by biphasic peaks of ethylene production after lysoPC 18:1 treatment. This suggested that lysoPC (C18:1)-induced ethylene production was regulated at the transcriptional level of time-dependent gene members. LysoPC 18:1 treatment also rapidly induced cell damage. LysoPC 18:1-induced cell death was almost completely abrogated in ROS generation-impaired transgenic plants (rbohD-as and rbohF-as), ethylene production-impaired transgenic plants (CAS-AS and CAO-AS), and ethylene signaling-impaired transgenic plants (Ein3-AS), respectively. Taken together, pathogen-induced lysoPCs enhance pathogen susceptibility accompanied by ROS and ethylene biosynthesis, resulting in chlorophyll degradation and cell death. Expression of PR genes (PR1-a, PR-3, and PR-4b) and LOX3 was strongly induced in lysoPC 18:1-treated leaves, indicating the involvement of lysoPC 18:1 in the defense response. However, lysoPC 18:1 treatment eventually resulted in cell death, as evidenced by metacaspase gene expression. Therefore, a hypothesis is proposed that the antipathogenic potential of lysoPC 18:1 is dependent on how quickly it is removed from cells for avoidance of lysoPC toxicity.

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Posted on 21 July 2014 | 6:25 pm


Frank A. Loewus (1919–2014): A life well spent and well remembered

Publication date: Available online 4 July 2014
Source:Phytochemistry

Author(s): Norman G. Lewis







Posted on 21 July 2014 | 6:25 pm


Graphical Contents List

Publication date: July 2014
Source:Phytochemistry, Volume 103









Posted on 21 July 2014 | 6:25 pm


Editorial Board/Publication Information

Publication date: July 2014
Source:Phytochemistry, Volume 103









Posted on 21 July 2014 | 6:25 pm


Chemogeography and antimicrobial activity of essential oils from Geijera parviflora and Geijera salicifolia (Rutaceae): Two traditional Australian medicinal plants

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Nicholas J. Sadgrove , Maximilien Gonçalves-Martins , Graham L. Jones

Essential oils were hydrodistilled from 27 specimens of Geijera parviflora Lindl., (Rutaceae) and nine specimens of Geijera salicifolia Schott, collected over a wide geographic range in New South Wales, Queensland and South Australia. Essential oils were produced by traditional hydrodistillation and characterised using GC–MS. From one specimen a serendipitous discovery was made of bioactive coumarins dissolved in the hydrosol, which were the coumarins isopsoralen, xanthyletine and osthole. These coumarins were not present in the essential oil from that specimen. Using essential oil composition from all specimens, principal component analysis (PCA) demonstrated nine clusters for G. parviflora and three for G. salicifolia. Some clusters are representative of previously described chemotypes and some are reflective of possible chemotypes requiring more comprehensive sampling for confirmation. Thus, another three or four possible chemotypes of G. parviflora and one of G. salicifolia have been tentatively identified. Using micro-titre plate broth dilution assays, antibacterial and antifungal activity of all chemotypes was investigated. In this regard, the ‘green oil’ chemotype, restricted to G. parviflora, with major components linalool, geijerene/pregeijerene, 1,8-cineol and bicyclogermacrene, demonstrated the highest antimicrobial and free radical scavenging activity. Thus, in the light of traditional use reports of local analgaesia and bioactivity demonstrated in the current study, oils from select chemotypes of G. parviflora may be useful in suitably compounded lotions and creams designed for topical antimicrobial applications and local pain relief. In addition, because major components are known for insecticidal activities, such lotions may also be useful as topically applied insect repellents.

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Posted on 21 July 2014 | 6:25 pm


Cytotoxic dimeric quinolone–terpene alkaloids from the root bark of Zanthoxylum rhetsa

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Monira Ahsan , Mohammad Rashedul Haque , Md. Belayet Hossain , Sheikh Nazrul Islam , Alexander I. Gray , Choudhury Mahmood Hasan

Four quinolone–terpene alkaloids, chelerybulgarine (1), 2?-episimulanoquinoline (3), 2,11-didemethoxyvepridimerine B (4), and rhetsidimerine (5) were isolated from the root bark of Zanthoxylum rhetsa DC. Chelerybulgarine (1) is a C–C linked terpene alkaloid where the C-6 of dihydrochelerythrine is linked to C-11 of the sesquiterpenoid 10?-methoxybulgarene. 2?-Episimulanoquinoline is a dimeric alkaloid containing dihydrochelerythrine and 8-methoxy-N-methylflindersine moieties, whereas 2,11-didemethoxyvepridimerine B and rhetsidimerine are dimeric prenylated quinolone alkaloids. Seven of the isolated compounds exhibited weak cytotoxicity when tested against a panel of six human stomach-cancer cell lines.

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Posted on 21 July 2014 | 6:25 pm


The effect of drought stress on the expression of key genes involved in the biosynthesis of triterpenoid saponins in liquorice (Glycyrrhiza glabra)

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Vida Nasrollahi , Asghar Mirzaie-asl , Khosro Piri , Sonbol Nazeri , Rahim Mehrabi

Glycyrrhiza glabra is an important medicinal plant throughout the world. Glycyrrhizin is a triterpenoid that is among the most important secondary metabolites produced by liquorice. Drought stress is proposed to enhance the levels of secondary metabolites. In this study, the effect of drought stress on the expression of important genes involved in the glycyrrhizin biosynthetic pathway was examined. Drought stress at the seedling stage was applied to 8-day-old plants using polyethylene glycol. Subsequently, the samples were collected 0, 4, 8 or 24h post-treatment. At the adult plant stage, 10-month-old plants were subjected to drought stress by discontinuing irrigation. Subsequently, samples were collected at 2, 16 and 28days after drought imposition (S2d, S16d and S28d, respectively). We performed semi-quantitative RT-PCR assays to evaluate the gene expression levels of sequalene synthase (SQS), ?-amyrin synthase (bAS), lupeol synthase (LUS) and cycloartenol synthase (CAS) during stress. Finally, the glycyrrhizin content of stolons was determined via HPLC. The results revealed that due to osmotic stress, the gene expression levels of SQS and bAS were increased, whereas those of CAS were relatively unchanged at the seedling stage. At the adult plant stage, the expression levels of SQS and bAS were increased under drought stress conditions, whereas the gene expression level of CAS remained relatively constant. The glycyrrhizin content in stolons was increased only under severe drought stress conditions (S28d). Our results indicate that application of controlled drought stress up-regulates the expression of key genes involved in the biosynthesis of triterpenoid saponins and directly enhances the production of secondary metabolites, including glycyrrhizin, in liquorice plants.

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Highlights

Drought stress increased the amount of glycyrrhizin in the stolons of Glycyrrhiza glabra. The expression of sequalene synthase (SQS) and ?-amyrin synthase (bAS) genes were increased under drought stress, whereas expression of cycloartenol synthase (CAS) was not changed.





Posted on 21 July 2014 | 6:25 pm


PhDAHP1 is required for floral volatile benzenoid/phenylpropanoid biosynthesis in Petunia × hybrida cv ‘Mitchell Diploid’

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Kelly M. Langer , Correy R. Jones , Elizabeth A. Jaworski , Gabrielle V. Rushing , Joo Young Kim , David G. Clark , Thomas A. Colquhoun

Floral volatile benzenoid/phenylpropanoid (FVBP) biosynthesis consists of numerous enzymatic and regulatory processes. The initial enzymatic step bridging primary metabolism to secondary metabolism is the condensation of phosphoenolpyruvate (PEP) and erythrose-4-phosphate (E4P) carried out via 3-DEOXY-D-ARABINO-HEPTULOSONATE-7-PHOSPHATE (DAHP) synthase. Here, identified, cloned, localized, and functionally characterized were two DAHP synthases from the model plant species Petunia × hybrida cv ‘Mitchell Diploid’ (MD). Full-length transcript sequences for PhDAHP1 and PhDAHP2 were identified and cloned using cDNA SMART libraries constructed from pooled MD corolla and leaf total RNA. Predicted amino acid sequence of PhDAHP1 and PhDAHP2 proteins were 76% and 80% identical to AtDAHP1 and AtDAHP2 from Arabidopsis, respectively. PhDAHP1 transcript accumulated to relatively highest levels in petal limb and tube tissues, while PhDAHP2 accumulated to highest levels in leaf and stem tissues. Through floral development, PhDAHP1 transcript accumulated to highest levels during open flower stages, and PhDAHP2 transcript remained constitutive throughout. Radiolabeled PhDAHP1 and PhDAHP2 proteins localized to plastids, however, PhDAHP2 localization appeared less efficient. PhDAHP1 RNAi knockdown petunia lines were reduced in total FVBP emission compared to MD, while PhDAHP2 RNAi lines emitted ‘wildtype’ FVBP levels. These results demonstrate that PhDAHP1 is the principal DAHP synthase protein responsible for the coupling of metabolites from primary metabolism to secondary metabolism, and the ultimate biosynthesis of FVBPs in the MD flower.

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Posted on 21 July 2014 | 6:25 pm


Dibenzocyclooctadiene lignans from Schisandra chinensis and their inhibitory activity on NO production in lipopolysaccharide-activated microglia cells

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Di Hu , Zhiyou Yang , Xuechun Yao , Hua Wang , Na Han , Zhihui Liu , Yu Wang , Jingyu Yang , Jun Yin

Four dibenzocyclooctadiene lignans, schisanchinins A–D, and 10 known compounds were isolated from the EtOAc extract of fruits of Schisandra chinensis (Turcz.) Baill. Structures of compounds 14 were elucidated using a combination of spectroscopic techniques, including MS, UV and IR, NMR (1H NMR, 13C NMR, HMQC, HMBC). The stereochemistry of the chiral centers and the biphenyl configuration were determined using NOESY, as well as analysis of CD spectra. In vitro activity assays showed that 11 of the 14 compounds exhibited inhibitory activity on lipopolysaccharide (LPS)-induced NO release in primary murine BV2 microglia cells.

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Posted on 21 July 2014 | 6:25 pm


Nitrogen supply affects anthocyanin biosynthetic and regulatory genes in grapevine cv. Cabernet-Sauvignon berries

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Eric Soubeyrand , Cyril Basteau , Ghislaine Hilbert , Cornelis van Leeuwen , Serge Delrot , Eric Gomès

Accumulation of anthocyanins in grape berries is influenced by environmental factors (such as temperature and light) and supply of nutrients, i.e., fluxes of carbon and nitrogen feeding the berry cells. It is established that low nitrogen supply stimulates anthocyanin production in berry skin cells of red varieties. The present works aims to gain a better understanding of the molecular mechanisms involved in the response of anthocyanin accumulation to nitrogen supply in berries from field grown-plants. To this end, we developed an integrated approach combining monitoring of plant nitrogen status, metabolite measurements and transcript analysis. Grapevines (cv. Cabernet-Sauvignon) were cultivated in a vineyard with three nitrogen fertilization levels (0, 60 and 120kgha?1 of nitrogen applied on the soil). Anthocyanin profiles were analyzed and compared with gene expression levels. Low nitrogen supply caused a significant increase in anthocyanin levels at two ripening stages (26days post-véraison and maturity). Delphinidin and petunidin derivatives were the most affected compounds. Transcript levels of both structural and regulatory genes involved in anthocyanin synthesis confirmed the stimulation of the phenylpropanoid pathway. Genes encoding phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), flavonoid-3?,5?-hydroxylase (F3?5?H), dihydroflavonol-4-reductase (DFR), leucoanthocyanidin dioxygenase (LDOX) exhibited higher transcript levels in berries from plant cultivated without nitrogen compared to the ones cultivated with 120kgha?1 nitrogen fertilization. The results indicate that nitrogen controls a coordinated regulation of both positive (MYB transcription factors) and negative (LBD proteins) regulators of the flavonoid pathway in grapevine.

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Posted on 21 July 2014 | 6:25 pm


The floral scents of Nymphaea subg. Hydrocallis (Nymphaeaceae), the New World night-blooming water lilies, and their relation with putative pollinators

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Artur Campos Dália Maia , Carla Teixeira de Lima , Daniela Maria do Amaral Ferraz Navarro , Marion Chartier , Ana Maria Giulietti , Isabel Cristina Machado

Night-blooming water lilies are characterized by intense emission of floral VOCs. Their unique scent-oriented pollinators, cyclocephaline scarabs (Scarabaeidae, Cyclocephalini), are attracted to flowers that they use as reliable sources of food and as mating aggregation sites. Chemical analysis of floral scent samples of seven species of Nymphaea subg. Hydrocallis established remarkably simple fragrant blends, each of which was dominated by one or two prominent compounds that alone accounted for over 95% of total scent emission. A total of 22 VOCs were identified: aliphatics (9), C5-branched chain compounds (5) and aromatics (8). Anisole was the dominant constituent in the floral scents of Nymphaea amazonum subsp. amazonum, N. amazonum subsp. pedersenii and N. tenerinervia, whereas (methoxymethyl)benzene was the most abundant VOC in samples of N. lasiophylla and N. lingulata. Flowers of N. rudgeana and N. gardneriana emitted high amounts of methyl hexanoate and methyl 2-methylbutanoate. Comparisons of floral VOC composition including other day- and night-blooming species of Nymphaea and Victoria obtained from the literature evidenced disparities related to habitus. While flowers of day-blooming species mostly emit aromatic alcohols and ethers, nocturnal species are particularly rich in aromatic ethers, aliphatic esters and C5-branched chain esters. These findings strongly suggest that the floral scent composition within closely related Nymphaea and Victoria is linked to pollinator selection, and the putative role of floral VOCs in pollinator attractiveness is discussed.

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Highlights

Night-blooming water lilies are characterized by intense emission of floral VOCs, notably aromatic ethers, aliphatic esters and C5-branched chain esters.





Posted on 21 July 2014 | 6:25 pm


Wounding stress causes rapid increase in concentration of the naturally occurring 2?,3?-isomers of cyclic guanosine- and cyclic adenosine monophosphate (cGMP and cAMP) in plant tissues

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Thomas Van Damme , Dieter Blancquaert , Pauline Couturon , Dominique Van Der Straeten , Pat Sandra , Frédéric Lynen

3?,5?-Cyclic guanosine monophosphate (cGMP) and 3?,5?-cyclic adenosine monophosphate (cAMP) are well reported second messenger molecules involved in cellular signal transduction, in physiological functions such as neurotransmission in animals and in the modulation of cell growth and differentiation. In plants, 3?,5?-cyclic nucleotides have been implicated in the regulation of ion homeostasis, hormone and stress responses. The behavior of the 2?,3?-cyclic nucleotide variants is also known in animal tissue but no quantitative information is available about 2?,3?-cAMP and 2?,3?-cGMP in plant material. A recently developed HILIC–SPE/LC–MS/MS method for the analysis of cyclic nucleotides in blood and animal tissue was therefore adapted to measure 2?,3?-cAMP and 2?,3?-cGMP concentrations in plant material. Cyclic nucleotide concentrations were measured in Arabidopsis thaliana (Col-0) leaves before and after the application of wounding stress. A significant (?5-fold) up-regulation of 2?,3?-cAMP and 2?,3?-cGMP was measured in Arabidopsis leaves compared to the control samples. The results indicate a thus far unreported strong correlation between plant stress and both 2?,3?-cAMP and 2?,3?-cGMP levels in plant material, and may open new avenues towards understanding the role of cyclic nucleotides in plants.

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Posted on 21 July 2014 | 6:25 pm


Lathyrane-type diterpenoids from the seeds of Euphorbia lathyris

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Jin Lu , Guoyu Li , Jian Huang , Cui Zhang , Lan Zhang , Ke Zhang , Pingya Li , Ruichao Lin , Jinhui Wang

Ten lathyrane-type diterpenoids named Euphorbia Factor L12–L21 (110) and twelve known diterpenoids (1122) were isolated from seeds of Euphorbia lathyris. The structures of these compounds were determined by extensive spectroscopic (UV, IR, HRESIMS, 1D and 2D NMR) analyses. In addition, the configuration of Euphorbia Factor L12 (1) was further confirmed by X-ray crystallographic and circular dichroism (CD) analyses. A putative biogenetic relationship to these compounds was proposed. Cytotoxicity of the isolated compounds against C6 and MCF-7 cell lines were evaluated. Compounds 1, 5, 7, 12 and 17 exhibited considerable cytotoxic activities (IC50 12.4–36.2?M).

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Posted on 21 July 2014 | 6:25 pm


Rapid estimation of the oxidative activities of individual phenolics in crude plant extracts

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Matti Vihakas , Maija Pälijärvi , Maarit Karonen , Heikki Roininen , Juha-Pekka Salminen

Previous studies of purified phenolic compounds have revealed that some phenolics, especially ellagitannins, can autoxidise under alkaline conditions, which predominate in the midgut of lepidopteran larvae. To facilitate screening for the pro-oxidant activities of all types of phenolic compounds from crude plant extracts, we developed a method that combined our recent spectrophotometric bioactivity method with an additional chromatographic step via UPLC–DAD–MS. This method allowed us to estimate the total pro-oxidant capacities of crude extracts from 12 plant species and to identify the individual phenolic compounds that were responsible for the detected activities. It was found that the pro-oxidant capacities of the plant species (i.e., the concentrations of the easily-oxidised phenolics) varied from 0 to 57mg/g dry wt, representing from 0% to 46% of the total phenolics from different species. UPLC–DAD–MS analysis revealed that most flavonol and flavone glycosides were only slightly affected by alkaline conditions, thus indicating their low pro-oxidant activity. Interestingly, myricetin-type compounds differed from the other flavonoids, as their concentrations decreased strongly due to alkaline incubation. The same effect was detected for hydrolysable tannins and prodelphinidins, suggesting that a pyrogallol sub-structure could be a key structural component that partially explains their easy oxidation at high pH. Other types of phenolic compounds, such as hydroxycinnamic acids, were relatively active, as well. These findings demonstrate that this method displays the potential to identify most of the active and inactive pro-oxidant phenolic compounds in various plant species.

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Posted on 21 July 2014 | 6:25 pm


Oleanane triterpenes as protein tyrosine phosphatase 1B (PTP1B) inhibitors from Camellia japonica

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Mohammad Nasir Uddin , Govinda Sharma , Jun-Li Yang , Hong Seok Choi , Seong-IL Lim , Keon Wook Kang , Won Keun Oh

Protein tyrosine phosphatase 1B (PTP1B) plays a key role in metabolic signaling, thereby making it an exciting drug target for type 2 diabetes and obesity. Besides, there is substantial evidence that shows its overexpression is involved in breast cancer, which suggests that selective PTP1B inhibition might be effective in breast cancer treatment. As part of our continuous research on PTP1B inhibitors from medicinal plants, four oleanane-type triterpenes were isolated from an EtOAc-soluble extract of fruit peels of Camellia japonica (Theaceae), together with 6 previously known compounds of this class. Their structures were determined on the basis of spectroscopic data analysis (UV, IR, 1H and 13CNMR, HMBC, HSQC, NOESY, and MS). All isolates were evaluated for their inhibitory effects on PTP1B, as well as their cytotoxic effects against human breast cancer cell lines MCF7, MCF7/ADR, and MDA-MB-231. Several compounds with OH-3 or/and COOH-28 functionalities showed strong PTP1B inhibitory activity (IC50 values ranging from 3.77±0.11 to 6.40±0.81?M) as well as significant cytotoxicity (IC50 values ranging from 0.51±0.05 to 13.55±1.44?M).

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Highlights

Four (14) along with six known oleanane-type triterpenes were isolated from fruit peels of Camellia japonica (Theaceae). Several compounds with OH-3 or/and COOH-28 functionalities showed strong PTP1B inhibitory activity as well as cytotoxicity against human breast cancer cell lines.





Posted on 21 July 2014 | 6:25 pm


Biological evaluation of secondary metabolites from the roots of Myrica adenophora

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Ya-Chih Ting , Horng-Huey Ko , Hui-Chun Wang , Chien-Fang Peng , Hsun-Shuo Chang , Pei-Chen Hsieh , Ih-Sheng Chen

Bioassay-guided fractionation of the roots of Myrica adenophora led to isolation of 24 known compounds and hitherto unknown compounds, including three A-type proanthocyanidins [adenodimerins A–C], two esters of sucrose [myricadenins A and B ], and the phenolic glycoside 6?-O-galloyl orbicularin. Spectroscopic analyses were used to determine their structures. Adenodimerin A, myricananin C, and myricetin showed strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, with SC50 values of 7.9, 16.3, and 15.9?M, respectively. Adenodimerin A, myricanone, myricananin C, (?)-myricanol, myricanol 11-O-?-d-glucopyranoside, and myricetin showed stronger 2,2?-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) radical scavenging activities than the positive control, with SC50 values of 7.5, 19.6, 12.0, 22.3, 19.6, and 15.6?M, respectively. 5-Deoxymyricanone, porson, 12-hydroxymyricanone (?)-myricanol, and (+)-galeon exhibited anti-tubercular activity against Mycobacterium tuberculosis H37Rv in vitro and MICs values of 25.8, 40.0, 35.8, 30.0, and 15.0?g/mL, respectively. Myricadenin A, myricanone, myricananin C, and (?)-myricanol exhibited anti-inflammatory activities in the iNOS assay with EC50 values of 18.1, 1.00, 13.0, and 7.5?M, respectively.

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Posted on 21 July 2014 | 6:25 pm


Chemical constituents from cultures of the basidiomycete Trichaptum pargamenum

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Xiao-Yan Yang , Tao Feng , Gang-Qiang Wang , Jian-Hai Ding , Zheng-Hui Li , Yan Li , Shuang-Hui He , Ji-Kai Liu

Four cadinane-type sesquiterpenes and four 13-carbon ?-lactones, together with three known compounds, were isolated from cultures of the basidiomycete Trichaptum pargamenum. Their structures were elucidated on the basis of extensive spectroscopic methods. The absolute configurations of two of the cadinene type sesquiterpenes 1 and 3 were confirmed by single crystal X-ray diffractions.

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Posted on 21 July 2014 | 6:25 pm


Biofilm blocking sesquiterpenes from Teucrium polium

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Wael A. Elmasri , Mohamed-Elamir F. Hegazy , Mina Aziz , Ekrem Koksal , Wail Amor , Yehia Mechref , Abdul N. Hamood , David B. Cordes , Paul W. Paré

The chemical composition and antibacterial activity of Teucrium polium L. (Lamiaceae) were assessed; sixteen compounds were isolated from a CH2Cl2/MeOH extract of the aerial parts of the plant including four sesquiterpenes 4?,5?-epoxy-7?H-germacr-10(14)-en-6?-ol-1-one, 4?,5?-epoxy-7?H-germacr-10(14)-en,1?-hydroperoxyl,6?-ol, 4?,5?-epoxy-7?H-germacr-10(14)-en,1?-hydroperoxyl,6?-ol and 4?,5?-epoxy-7?H-germacr-10(14)-en,1?-hydroperoxyl,6?-ol, together with seven known sesquiterpenes, one known iridoid glycoside, two known flavonoids, and one known phenylpropanoid glycoside. Structures were elucidated on the basis of spectroscopic (UV, 1H and 13C NMR) data, as well as two-dimensional NMR (1H–1H COSY, HMQC, NOESY and HMBC), and ESI-MS analysis. The relative stereochemistry of the ketone was established by X-ray crystallography, while its absolute configuration was attained by a modified Mosher’s method. Antibacterial activity of the crude extract, as well as with four of the isolated metabolites, was observed with Staphylococcus aureus anti-biofilm activity in the low ?Mol range. Diverse sesquiterpene-skeleton structure and corresponding comprehensive enzyme capacity is discussed.

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Posted on 21 July 2014 | 6:25 pm


Acylated flavonol glycosides from the flower of Elaeagnus angustifolia L.

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Sarah Bendaikha , Méredith Gadaut , Dominique Harakat , Alabdul Magid

Seven acylated flavonol glycosides named elaeagnosides A–G, in addition to seven known flavonoids were isolated from the flowers of Elaeagnus angustifolia. Their structures were elucidated by different spectroscopic methods including 1D, 2D NMR experiments and HR-ESI-MS analysis. In order to identify natural antioxidant and tyrosinase inhibitor agents, the abilities of these flavonoids to scavenge the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and to inhibit tyrosinase activity were evaluated. Results revealed that two of these compounds had significant anti-oxidant effect and one compound showed weak tyrosinase-inhibitory activity compared with kojic acid, quercetin, or ascorbic acid, which were used as positive control.

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Posted on 21 July 2014 | 6:25 pm


Bisbenzylisoquinoline and hasubanane alkaloids from Stephania abyssinica (Dillon & A. Rich) (Menispermeceae)

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Ruth A. Omole , Jeremiah Gathirwa , Hosea Akala , Hamisi M. Malebo , Alex K. Machocho , Ahmed Hassanali , Isaiah O. Ndiege

Two bisbenzylisoquinoline and one hasubanane alkaloids: (?)-pseudocurine (1), (?)-pseudoisocurine (2) and (?)-10-oxoaknadinine (3), were isolated from leaf extract of Stephania abyssinica, a plant used in traditional medicine in South Nyanza region of Kenya. They were characterized using 1D (1H, 13C and DEPT) and 2D (COSY, NOESY, HMQC and HMBC) NMR techniques. (?)-Pseudocurine (1) and (?)-pseudoisocurine (2) exhibited strong to moderate anti-plasmodial activity while (?)-10-oxoaknadinine (3) showed moderate to mild activity.

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Posted on 21 July 2014 | 6:25 pm


Production of structured triacylglycerols from microalgae

Publication date: August 2014
Source:Phytochemistry, Volume 104

Author(s): Tomáš ?ezanka , Jaromír Lukavský , Linda Nedbalová , Karel Sigler

Structured triacylglycerols (TAGs) were isolated from nine cultivated strains of microalgae belonging to different taxonomic groups, i.e. Audouinella eugena, Balbiania investiens, Myrmecia bisecta, Nannochloropsis limnetica, Palmodictyon varium, Phaeodactylum tricornutum, Pseudochantransia sp., Thorea ramosissima, and Trachydiscus minutus. They were separated and isolated by means of NARP-LC/MS-APCI and chiral LC and the positional isomers and enantiomers of TAGs with two polyunsaturated, i.e. arachidonic (A) and eicosapentaenoic (E) acids and one saturated, i.e. palmitic acid (P) were identified. Algae that produce eicosapentaenoic acid were found to biosynthesize more asymmetrical TAGs, i.e. PPE or PEE, whereas algae which produced arachidonic acid give rise to symmetrical TAGs, i.e. PAP or APA, irrespective of their taxonomical classification. Nitrogen and phosphorus starvation consistently reversed the ratio of asymmetrical and symmetrical TAGs.

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Posted on 21 July 2014 | 6:25 pm


Isolation and characterization of six labdane diterpenes and one pregnane steroid of Turraeanthus africanus

Publication date: July 2014
Source:Phytochemistry, Volume 103

Author(s): Laurice Bracine Njanang Chenda , Simeon Fogue Kouam , Marc Lamshöft , Souvik Kusari , Ferdinand Mouafo Talontsi , Bonaventure Tchaleu Ngadjui , Michael Spiteller

Six labdane diterpene derivatives, named turraeanins F–J (36, 8) and epi-turraeanin J (7), and a pregnane steroid derivative named turraeasterodionene (2), were isolated by preparative high performance liquid chromatography together with thirteen known compounds from the Cameroonian medicinal plant Turraeanthus africanus. Their structures were elucidated by means of nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry in conjunction with the published data for the analogs, as well as the fragmentation patterns of each compound. Most of the known compounds were obtained for the first time from this plant. The compounds (27) were tested for their antibacterial efficacies against both Gram-positive and Gram-negative bacteria, including some clinically-important Risk group 2 human pathogens. Compound 4 exhibited the most pronounced antibacterial effectiveness comparable to standard reference streptomycin, with more potency against Gram-positive than Gram-negative bacteria. By comparing compounds 3, 4 and 5, a tentative structure–activity relationship could be drawn; selected oxidations at C-16 and C-18 drastically reduced the antibacterial efficacy of the parent compound (4). These results revealed the potential of compound 4 as a suitable antibacterial lead compound that might be used for further development of other derivatives to increase the antimicrobial efficacy.

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Posted on 21 July 2014 | 6:25 pm





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