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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:



Composition of polyphenol and polyamide compounds in common ragweed (Ambrosia artemisiifolia L.) pollen and sub-pollen particles

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Luka Mihajlovic , Jelena Radosavljevic , Lidija Burazer , Katarina Smiljanic , Tanja Cirkovic Velickovic

Phenolic composition of Ambrosia artemisiifolia L. pollen and sub-pollen particles (SPP) aqueous extracts was determined, using a novel extraction procedure. Total phenolic and flavonoid content was determined, as well as the antioxidative properties of the extract. Main components of water-soluble pollen phenolics are monoglycosides and malonyl-mono- and diglycosides of isorhamnetin, quercetin and kaempferol, while spermidine derivatives were identified as the dominant polyamides. SPP are similar in composition to pollen phenolics (predominant isorhamnetin and quercetin monoglycosides), but lacking small phenolic molecules (<450Da). Ethanol-based extraction protocol revealed one-third lower amount of total phenolics in SPP than in pollen. For the first time in any pollen species, SPP and pollen phenolic compositions were compared in detail, with an UHPLC/ESI-LTQ-Orbitrap-MS–MS approach, revealing the presence of spermidine derivatives in both SPP and pollen, not previously reported in Ambrosia species.

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Posted on 22 December 2014 | 8:33 am


Triterpene saponins from Eryngium kotschyi

Publication date: Available online 15 December 2014
Source:Phytochemistry

Author(s): Sinem Aslan Erdem , Anne-Claire Mitaine-Offer , Tomofumi Miyamoto , Murat Kartal , Marie-Aleth Lacaille-Dubois

Four new oleanane-type saponins 3-O-?-l-rhamnopyranosyl-(1?4)-?-d-glucuronopyranosyl-22-O-?,?-dimethylacryloylA1-barrigenol (1), 3-O-?-l-rhamnopyranosyl-(1?4)-?-d-glucuronopyranosyl-22-O-angeloylA1-barrigenol (2), 3-O-?-d-glucopyranosyl-(1?2)-[?-d-glucopyranosyl-(1?6)]-?-d-glucopyranosyl-21,22,28-O-triacetyl-(3?,21?,22?)-olean-12-en-16-one (3), and 3-O-?-d-glucopyranosyl-(1?2)-glucopyranosyl-22-O-?-d-glucopyranosylsteganogenin (4), along with the known 3-O-?-d-galactopyranosyl-(1?2)-[?-l-arabinopyranosyl-(1?3)]-?-d-glucuronopyranosyl-22-O-angeloylA1-barrigenol and 3-O-?-l-rhamnopyranosyl-(1?4)-?-d-glucuronopyranosyloleanolic acid, were isolated from a methanol extract of the roots of Eryngium kotschyi by multiple chromatographic steps. Saponins 3 and 4 are unusual by the original structure of their aglycon. Compound 3 possessed an oleanane-type skeleton with a 21,22,28-triacetylation and a ketone function at the C-16 position. For compound 4, the 17,22-seco-oleanolic acid skeleton is rarely found in natural saponins.

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Posted on 22 December 2014 | 8:33 am


Diversity of pyrrolizidine alkaloids in native and invasive Senecio pterophorus (Asteraceae): Implications for toxicity

Publication date: December 2014
Source:Phytochemistry, Volume 108

Author(s): Eva Castells , Patrick P.J. Mulder , Míriam Pérez-Trujillo

Changes in plant chemical defenses after invasion could have consequences on the invaded ecosystems by modifying the interactions between plants and herbivores and facilitating invasion success. However, no comprehensive biogeographical studies have yet determined the phenotypic levels of plant chemical defenses, as consumed by local herbivores, covering large distributional areas of a species. Senecio pterophorus is a perennial shrub native to Eastern South Africa, expanded into Western South Africa and introduced into Australia and Europe. As other Asteraceae, S. pterophorus contains pyrrolizidine alkaloids (PAs) toxic to vertebrate and invertebrate herbivores. Here we analyzed S. pterophorus PAs by LC–MS/MS on foliage sampled across its entire distributional range, including the native and all non-native areas. PA concentrations and diversity was very high: we found 57 compounds belonging to 6 distinct necine base-types, including the highly toxic 1,2-unsaturated PAs (retronecine and otonecines) and the less toxic 1,2-saturated PAs (platynecine and rosmarinecines). Plants from different origins diverged in their PA absolute and relative concentrations. Rosmarinine was the most abundant compound in Australia and South Africa, but it was nearly absent in Europe. We characterized three plant chemotypes: retrorsine–senkirkine chemotype in Eastern South Africa, rosmarinine chemotype in Australia and Western South Africa, and acetylseneciphylline chemotype in Europe. PA absolute concentrations were highest in Australia. The increased absolute and relative concentrations of retronecine PAs from Australia and Europe, respectively, indicate that S. pterophorus is potentially more toxic in the invasive range than in the native range.

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Posted on 22 December 2014 | 8:33 am


Corrigendum to “Cananginones A–I, linear acetogenins from the stem bark of Cananga latifolia” [Phytochemistry 72 (14-15) (2011) 1859–1864]

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Nikhom Wongsa , Somdej Kanokmedhakul , Kwanjai Kanokmedhakul







Posted on 22 December 2014 | 8:33 am


Graphical Contents List

Publication date: January 2015
Source:Phytochemistry, Volume 109









Posted on 22 December 2014 | 8:33 am


A tocotrienol series with an oxidative terminal prenyl unit from Garcinia amplexicaulis

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Alexis Lavaud , Pascal Richomme , Julia Gatto , Marie-Christine Aumond , Cyril Poullain , Marc Litaudon , Ramaroson Andriantsitohaina , David Guilet

Ten tocotrienol derivatives, i.e., amplexichromanols (110), were isolated from stem bark of Garcinia amplexicaulis Vieill. ex Pierre collected in Caledonia. The structures of the compounds 15 were determined to be chromanol derivatives substituted by a polyprenyl chain oxidized in terminal position. The remaining compounds 610 are the corresponding dimeric derivatives. Eleven known compounds, including xanthones, tocotrienol derivatives, triterpenes and phenolic compounds, were also isolated. Their structures were mainly determined using one and two-dimensional NMR and mass spectroscopy analysis. The compounds and some amplexichromanol molecules formerly isolated from G. amplexicaulis exhibited significant antioxidant activity against lipid peroxidation and in the ORAC assay.

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Posted on 22 December 2014 | 8:33 am


Developmental changes in leaf phenolics composition from three artichoke cvs. (Cynara scolymus) as determined via UHPLC–MS and chemometrics

Publication date: December 2014
Source:Phytochemistry, Volume 108

Author(s): Amira S. El Senousy , Mohamed A. Farag , Dalia A. Al-Mahdy , Ludger A. Wessjohann

The metabolomic differences in phenolics from leaves derived from 3 artichoke cultivars (Cynara scolymus): American Green Globe, French Hyrious and Egyptian Baladi, collected at different developmental stages, were assessed using UHPLC–MS coupled to chemometrics. Ontogenic changes were considered as leaves were collected at four different time intervals and positions (top and basal) during artichoke development. Unsupervised principal component analysis (PCA) and supervised orthogonal projection to latent structures-discriminant analysis (O2PLS-DA) were used for comparing and classification of samples harvested from different cultivars at different time points and positions. A clear separation among the three investigated cultivars was revealed, with the American Green Globe samples found most enriched in caffeic acid conjugates and flavonoids vs. other cultivars. Furthermore, these metabolites also showed a marked effect on the discrimination between leaf samples from cultivars harvested at different positions, regardless of the plant age. Metabolite absolute quantifications further confirmed that discrimination was mostly influenced by phenolic compounds, namely caffeoylquinic acids and flavonoids. This study demonstrates an effect of artichoke leaf position, regardless of plant age, on its secondary metabolites composition. To the best of our knowledge, this is the first report for compositional differences among artichoke leaves, based on their positions, via a metabolomic approach and suggesting that top positioned artichoke leaves present a better source of caffeoylquinic acids, compared to basal ones.

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Posted on 22 December 2014 | 8:33 am


Diels–Alder adducts with PTP1B inhibition from Morus notabilis

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Meng Wang , Li-Xin Gao , Jue Wang , Jing-Ya Li , Mei-Hua Yu , Jia Li , Ai-Jun Hou

Eight Diels–Alder adducts, morbilisins A–H (18), a known analogue, chalcomoracin (9), together with eleven known flavonoids and 2-arylbenzofurans, were isolated from the leaves of Morus notabilis. Their structures were elucidated by extensive spectroscopic analysis, including 1D, 2D NMR, MS, and ECD data. Compounds 1, 5, and 79 showed inhibition against PTP1B phosphatase activity in vitro.

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Posted on 22 December 2014 | 8:33 am


Purification of ?5-3-ketosteroid isomerase from Digitalis lanata

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Nadine Meitinger , Daniel Geiger , Thierry W. Augusto , Rodrigo Maia de Pádua , Wolfgang Kreis

The isomerization of 5-pregnene-3,20-dione into 4-pregnene-3,20-dione was investigated to shed further light on cardenolide biosynthesis and to characterize the enzymes involved in cardenolide formation. It was shown that the ?5-3-ketosteroid isomerase of Digitalis lanata, which catalyzes this isomerization, is an individual enzyme and not, as previously thought, associated with ?5-3?-hydroxysteroid dehydrogenase. The enzyme was purified by fractionated ammonium sulfate precipitation, hydrophobic interaction chromatography and gel filtration. The purification protocol resulted in a 68.1-fold enriched specific enzyme activity with a yield of 2.2%. After an additional chromatofocusing step the 3KSI activity appeared as a single protein band at 17kDa in SDS–PAGE. Plant 3KSI displayed similar properties to microbial 3-ketosteroid isomerases.

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Posted on 22 December 2014 | 8:33 am


NMR spectroscopic search module for Spektraris, an online resource for plant natural product identification – Taxane diterpenoids from Taxus×media cell suspension cultures as a case study

Publication date: Available online 19 December 2014
Source:Phytochemistry

Author(s): Justin T. Fischedick , Sean R. Johnson , Raymond E.B. Ketchum , Rodney B. Croteau , B. Markus Lange

Development and testing of Spektraris-NMR, an online spectral resource, is reported for the NMR-based structural identification of plant natural products (PNPs). Spektraris-NMR allows users to search with multiple spectra at once and returns a table with a list of hits arranged according to the goodness of fit between query data and database entries. For each hit, a link to a tabulated alignment of 1H NMR and 13C NMR spectroscopic peaks (query versus database entry) is provided. Furthermore, full spectroscopic records and experimental meta information about each database entry can be accessed online. To test the utility of Spektraris-NMR for PNP identification, the database was populated with NMR data (total of 466 spectra) for ?250 taxanes, which are structurally complex diterpenoids (including the anticancer drug taxol) commonly found in the genus Taxus. NMR data generated with metabolites purified from Taxus cell suspension cultures were then used to search Spektraris-NMR, and enabled the identification of eight taxanes with high confidence. A ninth isolated metabolite could be assigned, based on spectral searches, to a taxane skeletal class, but no high confidence hit was produced. Using various spectroscopic methods, this metabolite was characterized as 2-deacetylbaccatin IV, a novel taxane. These results indicate that Spektraris-NMR is a valuable resource for rapid and reliable identification of known metabolites and has the potential to contribute to de-replication efforts in novel PNP discovery.

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Posted on 22 December 2014 | 8:33 am


Effects of synthetic alkamides on Arabidopsis fatty acid amide hydrolase activity and plant development

Publication date: Available online 6 December 2014
Source:Phytochemistry

Author(s): Lionel Faure , Ronaldo Cavazos , Bibi Rafeiza Khan , Robby A. Petros , Peter Koulen , Elison B. Blancaflor , Kent D. Chapman

Alkamides and N-acylethanolamines (NAEs) are bioactive, amide-linked lipids that influence plant development. Alkamides are restricted to several families of higher plants and some fungi, whereas NAEs are widespread signaling molecules in both plants and animals. Fatty acid amide hydrolase (FAAH) has been described as a key contributor to NAE hydrolysis; however, no enzyme has been associated with alkamide degradation in plants. Herein reported is synthesis of 12 compounds structurally similar to a naturally occurring alkamide (N-isobutyl-(2E,6Z,8E)decatrienamide or affinin) with different acyl compositions more similar to plant NAEs and various amino alkyl head groups. These “hybrid” synthetic alkamides were tested for activity toward recombinant Arabidopsis FAAH and for their effects on plant development (i.e., cotyledon expansion and primary root length). A substantial increase in FAAH activity was discovered toward NAEs in vitro in the presence of some of these synthetic alkamides, such as N-ethyllauroylamide (4). This “enhancement” effect was found to be due, at least in part, to relief from product inhibition of FAAH by ethanolamine, and not due to an alteration in the oligomerization state of the FAAH enzyme. For several of these alkamides, an inhibition of seedling growth was observed with greater results in FAAH knockouts and less in FAAH over-expressing plants, suggesting that these alkamides could be hydrolyzed by FAAH in planta. The tight regulation of NAE levels in vivo appears to be important for proper seedling establishment, and as such, some of these synthetic alkamides may be useful pharmacological tools to manipulate the effects of NAEs in situ.

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Posted on 22 December 2014 | 8:33 am


Editorial Board/Publication Information

Publication date: December 2014
Source:Phytochemistry, Volume 108









Posted on 22 December 2014 | 8:33 am


Arabidopsis thaliana ?-glucosidase BGLU15 attacks flavonol 3-O-?-glucoside-7-O-?-rhamnosides

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Jonathon Roepke , Gale G. Bozzo

Kaempferol and quercetin 3-O-?-glucoside-7-O-?-rhamnoside (K3G7R and Q3G7R, respectively) are major flavonol bisglycosides accumulating in Arabidopsis thaliana with synergistic abiotic stresses (i.e., nitrogen deficiency and low temperature, NDLT). However, these molecules disappear rapidly during recovery from NDLT. Typically, catabolism of related chemicals relies on ?-glucosidase (BGLU) action. Evidence for flavonol 3-O-?-glucoside-7-O-?-rhamnoside BGLU activity is provided here. Major losses of Q3G7R and K3G7R coincided with an approximate 250% induction in flavonol 3-O-?-glucoside-7-O-?-rhamnoside BGLU activity within 2days of NDLT recovery relative to plants cultured under nitrogen sufficiency and high temperature (NSHT, control). QTOF-MS/MS established the product of Q3G7R hydrolysis in the presence of Arabidopsis cell free extracts was quercetin 7-O-?-rhamnoside. A phylogenetic analysis of the Arabidopsis glycoside hydrolase family 1 identified BGLU15 (At2g44450) and five other members that cluster with Fabaceae hydrolases known to attack isoflavones and isoflavonoids, which are structurally somewhat related to flavonol 3-O-?-glucoside-7-O-?-rhamnosides. Real time quantitative PCR analysis established a 300% higher expression of BGLU15 within 1day of the recovery from NDLT relative to control plants; lower or negligible changes in expression were evident for the remaining BGLUs. Recombinant thioredoxin-His6-tagged mature BGLU15 protein was expressed in Escherichia coli and purified to homogeneity. A comparison of a wide spectrum of ?-glucosides showed that recombinant BGLU15 preferentially hydrolyses the 3-O-?-glucosides of flavonols, but does not attack quercetin 3-O-?-rhamnoside, quercetin 3-O-?-galactoside and rutin. BGLU15 displayed the highest catalytic efficiency for Q3G7R and K3G7R yielding their respective 7-O-rhamnosides as products; flavonol 3-O-glucosides were also attacked, albeit with lower efficiency. Together, it appears the loss of flavonol 3-O-?-glucoside-7-O-?-rhamnosides in Arabidopsis is dependent upon the enzyme-mediated cleavage of the 3-O-? linked glucose moiety.

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Posted on 22 December 2014 | 8:33 am


Comparative analysis of three Australian finger lime (Citrus australasica) cultivars: Identification of unique citrus chemotypes and new volatile molecules

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Estelle Delort , Alain Jaquier , Erik Decorzant , Christian Chapuis , Alessandro Casilli , Eric Frérot

The volatile constituents of the peel of three cultivars of Australian finger lime (Citrus australasica) were investigated: Alstonville, Judy’s Everbearing and Durham’s Emerald. Both qualitative and quantitative GC–MS analyses were performed on their peel solvent extract. The results showed that the unique phenotypes of finger lime are also correlated to unique molecular compositions. Each cultivar revealed a different chemotype: limonene/sabinene for cv. Alstonville, limonene/citronellal/isomenthone for cv. Judy’s Everbearing, and limonene/citronellal/ citronellol for cv. Durham’s Emerald. To the best of our knowledge, these chemotypes have never been reported in any other citrus species. Furthermore, the amounts of some volatile constituents (?-terpinene, ?-pinene, ?-pinene, citral), which are generally the major constituents besides limonene in lime species, were surprisingly low in the three cultivars. Comparative GC–MS analysis also showed that some volatile molecules tended to be specific to one cultivar and could therefore be considered as markers. Moreover six molecules were reported for the first time in a citrus extract and confirmed by synthesis. Heart-cutting enantioselective two-dimensional GC–MS was performed to determine the enantiomeric distribution of the major chiral constituents. The combined data on three finger lime cultivars gives evidence of their divergence from other citrus species.

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Posted on 22 December 2014 | 8:33 am


Multiple genes of mevalonate and non-mevalonate pathways contribute to high aconites content in an endangered medicinal herb, Aconitum heterophyllum Wall

Publication date: December 2014
Source:Phytochemistry, Volume 108

Author(s): Nikhil Malhotra , Varun Kumar , Hemant Sood , Tiratha Raj Singh , Rajinder Singh Chauhan

Aconitum heterophyllum Wall, popularly known as Atis or Patis, is an important medicinal herb of North-Western and Eastern Himalayas. No information exists on molecular aspects of aconites biosynthesis, including atisine- the major chemical constituent of A. heterophyllum. Atisine content ranged from 0.14% to 0.37% and total alkaloids (aconites) from 0.20% to 2.49% among 14 accessions of A. heterophyllum. Two accessions contained the highest atisine content with 0.30% and 0.37% as well as the highest alkaloids content with 2.22% and 2.49%, respectively. No atisine was detected in leaves and shoots of A. heterophyllum, thereby, suggesting that the biosynthesis and accumulation of aconite alkaloids occur mainly in roots. Quantitative expression analysis of 15 genes of MVA/MEP pathways in roots versus shoots, differing for atisine content (0–2.2 folds) showed 11–100 folds increase in transcript amounts of 4 genes of MVA pathway; HMGS, HMGR, PMK, IPPI, and 4 genes of MEP pathway; DXPS, ISPD, HDS, GDPS, respectively. The overall expression of 8 genes decreased to 5–12 folds after comparative expression analysis between roots of high (0.37%) versus low (0.14%) atisine content accessions, but their relative transcript amounts remained higher in high content accessions, thereby implying their role in atisine biosynthesis and accumulation. PCA analysis revealed a positive correlation between MVA/MEP pathways genes and alkaloids content. The current study provides first report wherein partial sequences of 15 genes of MVA/MEP pathways have been cloned and studied for their possible role in aconites biosynthesis. The outcome of study has potential applications in the genetic improvement of A. heterophyllum.

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Highlights

Combinatorial contribution of the MVA/MEP pathways genes was found to be correlated to high aconites content in A. heterophyllum providing insights for its genetic improvement.





Posted on 22 December 2014 | 8:33 am


Quinolone and indole alkaloids from the fruits of Euodia rutaecarpa and their cytotoxicity against two human cancer cell lines

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Nan Zhao , Zhan-Lin Li , Da-Hong Li , Ya-Ting Sun , Dong-Ting Shan , Jiao Bai , Yue-Hu Pei , Yong-Kui Jing , Hui-Ming Hua

Four quinolone alkaloids (14) and three indole alkaloids (2022), together with 30 known alkaloids (519, 2337), were isolated from the fruits of Euodia rutaecarpa. Their structures were established by spectroscopic analyses. The in vitro cytotoxic activities of these alkaloids against leukaemia HL-60 and prostate cancer PC-3 cell lines were evaluated.

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Posted on 22 December 2014 | 8:33 am


Fatty acid profiles from the plasma membrane and detergent resistant membranes of two plant species

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Laura Carmona-Salazar , Mohammed El Hafidi , Nora Gutiérrez-Nájera , Liliana Noyola-Martínez , Ariadna González-Solís , Marina Gavilanes-Ruíz

It is essential to establish the composition of the plant plasma membrane in order to understand its organization and behavior under continually changing environments. Knowledge of the lipid phase, in particular the fatty acid (FA) complex repertoire, is important since FAs determine many of the physical–chemical membrane properties. FAs are constituents of the membrane glycerolipid and sphingolipid backbones and can also be linked to some sterols. In addition, FAs are components of complex lipids that can constitute membrane micro-domains, and the use of detergent-resistant membranes is a common approach to study their composition. The diversity and cellular allocation of the membrane lipids containing FAs are very diverse and the approaches to analyze them provide only general information. In this work, a detailed FA analysis was performed using highly purified plasma membranes from bean leaves and germinating maize embryos and their respective detergent-resistant membrane preparations. The analyses showed the presence of a significant amount of very long chain FAs (containing 28C, 30C and 32C), in both plasma membrane preparations from bean and maize, that have not been previously reported. Herein is demonstrated that a significant enrichment of very long chain saturated FAs and saturated FAs can occur in detergent-resistant membrane preparations, as compared to the plasma membranes from both plant species. Considering that a thorough analysis of FAs is rarely performed in purified plasma membranes and detergent-resistant membranes, this work provides qualitative and quantitative evidence on the contributions of the length and saturation of FAs to the organization of the plant plasma membrane and detergent-resistant membranes.

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Posted on 22 December 2014 | 8:33 am


Withanolides from Physalis coztomatl

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Huaping Zhang , Cong-Mei Cao , Robert J. Gallagher , Victor W. Day , Kelly Kindscher , Barbara N. Timmermann

Six withanolides (16), as well as two known withanolides (physachenolide D 7 and withanoside VI 8), were isolated from the aerial parts of Physalis coztomatl (Solanaceae). Structural elucidations of 16 were achieved through 2D NMR and other spectroscopic techniques, while the structure of 1 was confirmed by X-ray crystallographic analysis. In addition, the stereochemical orientation of the 17-hydroxy group in withanolides was discussed in relation to 13C NMR shifts of C-12, 13, 14 and 16. Such analysis established that coagulansin A contains a 17?-hydroxy moiety rather than the reported 17?-hydroxy functionality, and has been revised accordingly.

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Antiproliferative quillaic acid and gypsogenin saponins from Saponaria officinalis L. roots

Publication date: Available online 19 December 2014
Source:Phytochemistry

Author(s): Yuping Lu , Dang Van , Leah Deibert , Greg Bishop , John Balsevich

Nine quillaic acid and five gypsogenin bisdesmosides were isolated from roots of Saponaria officinalis L. (Caryophyllaceae). Seven of the quillaic acid saponins possessed a 3-O-?-d-galactopyranosyl-(1?2)-[?-d-xylopyranosyl-(1?3)]-?-d-glucuronopyranosyl unit, but differed from each other in oligosaccharide units linked to the C-28 ester. The five gypsogenin saponins isolated from the roots all possessed the 3-O-?-d-galactopyranosyl-(1?2)-[?-d-xylopyranosyl-(1?3)]-?-d-glucuronopyranosyl unit, with their oligosaccharide units linked to the C-28 ester differing. Structures were elucidated by extensive 1D and 2D NMR spectroscopy and mass spectrometry. The saponins were evaluated for growth inhibitory activity in two human cancer cell lines and hemolytic activity in sheep red blood cells.

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Posted on 22 December 2014 | 8:33 am


Unusual cycloartane triterpenoids from Kadsura ananosma

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Jian-Hong Yang , Jian-Xin Pu , Jin Wen , Xiao-Nian Li , Fei He , Jia Su , Yan Li , Han-Dong Sun

Five 3,4-seco-cycloartane triterpenoids were isolated from the stems of Kadsura ananosma, two of which had rearranged 5/6 consecutive carbocycle rings C/D (trivially named ananosins A (1) and B (2)), one had a migrated CH3-18 (named ananosins C (3)), and two were analogs, ananosins D (4) and E (5). Their structures were characterized by comprehensive spectroscopic analysis, especially using 2D NMR spectra. A biogenetic pathway to 1 was proposed. These 5 compounds, together with 5 known analogs isolated from the same origin, were evaluated for their cytotoxicity against HL-60, SMMC-7721, A-549, PANC-1, and SK-BR-3 human cancer cells, but were inactive.

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Posted on 22 December 2014 | 8:33 am


Hypoglycemic and antihyperglycemic effects of phytopreparations and limonoids from Swietenia humilis

Publication date: Available online 19 December 2014
Source:Phytochemistry

Author(s): Berenice Ovalle-Magallanes , Omar N. Medina-Campos , José Pedraza-Chaverri , Rachel Mata

An aqueous extract from the seeds of Swietenia humilis (31.6–100mg/kg bw) lowered (p < 0.05) blood glucose levels in normal and nicotinamide–streptozotocin (NA–STZ)-induced hyperglycemic mice. Furthermore, when administered to fructose-fed rats with metabolic syndrome, the decoction showed significant antihyperglycemic, hypoglycemic and hypolipidemic effects, as well as an augmentation of hepatic glycogen. Limonoids 2-hydroxy-destigloyl-6-deoxyswietenine acetate (1), humulin B (2), methyl-2-hydroxy-3-?-isobutyroxy-1-oxomeliac-8(30)-enate (3), methyl-2-hydroxy-3-?-tigloyloxy-1-oxomeliac-8(30)-enate (4), humilinolide G (5), humilinolide C (6), methyl-2-hydroxy-3-?-isobutyoyl-8?,30?-epoxy-1-oxo-meliacate (7), and humilinolide H (8), were isolated from a CH2Cl2–MeOH (1:1) extract of the seeds. Compounds 5 and 8 are analogs of compounds 6 and 7. The structure of 5 was unequivocally established by X-ray analysis. When tested in normal and NA–STZ-hyperglycemic mice, compounds 1, 2, and 4 (3.16–31.6mg/kg bw) decreased glycemia during an oral glucose tolerance test. The present investigation sustains the contemporary popular uses of S. humilis seeds for treating metabolic disorders, including diabetes and dyslipidemia and demonstrates the potential of the mexicanolides as antihyperglycemic agents.

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Posted on 22 December 2014 | 8:33 am


Editorial Board/Publication Information

Publication date: January 2015
Source:Phytochemistry, Volume 109









Posted on 22 December 2014 | 8:33 am


Fruit-localized photoreceptors increase phenolic compounds in berry skins of field-grown Vitis vinifera L. cv. Malbec

Publication date: Available online 13 December 2014
Source:Phytochemistry

Author(s): Carina Verónica González , Martín Leandro Fanzone , Leandro Emanuel Cortés , Rubén Bottini , Diego Claudio Lijavetzky , Carlos Luis Ballaré , Hernán Esteban Boccalandro

Sunlight exposure has multiple effect on fruits, as it affects the light climate perceived by fruit photoreceptors and fruit tissue temperature. In grapes (Vitis vinifera L.), light exposure can have a strong effect on fruit quality and commercial value; however, the mechanisms of light action are not well understood. The role of fruit-localized photoreceptors in the control of berry quality traits was evaluated under field conditions in a commercial vineyard in Mendoza (Argentina). Characterization of the diurnal dynamics of the fruit light environment in a vertical trellis system indicated that clusters were shaded by leaves during most of the photoperiod. Supplementation of the fruit light environment from 20days before veraison until technological harvest showed that red (R, 660nm) and blue (B, 470nm) light strongly increased total phenolic compound levels at harvest in the berry skins without affecting sugar content, acidity or berry size. Far-red (FR, 730nm) and green (G, 560nm) light supplementation had relatively small effects. The stimulation of berry phytochromes and cryptochromes favored accumulation of flavonoid and non-flavonoid compounds, including anthocyanins, flavonols, flavanols, phenolic acids and stilbenes. These results demonstrate that the chemical composition of grape berries is modulated by the light quality received by the clusters under field conditions, and that fruit photoreceptors are not saturated even in areas of high insolation and under management systems that are considered to result in a relatively high exposure of fruits to solar radiation. Therefore, manipulation of the light environment or the light sensitivity of fruits could have significant effects on critical grape quality traits.

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Posted on 22 December 2014 | 8:33 am


Further iridoid glucosides in the genus Manulea (Scrophulariaceae)

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Chrysoula Gousiadou , Tetsuo Kokubun , Charlotte H. Gotfredsen , Søren R. Jensen

From Manulea altissima (Scrophulariaceae) were isolated five known secoiridoid glucosides sweroside, eustomoside, eustoside, secoxyloganin and secologanoside as well as the 4?-O-rhamnopyranosyl-feruloyl ester of adoxosidic acid, named altissimoside. Also, the caffeoyl phenylethanoid glycoside verbascoside was isolated. In addition two previously unknown terpenoid esters of 6?-hydroxy 8-epi-boschnaloside, named manucoside A and B were isolated from a formerly obtained fraction from the work-up of Manulea corymbosa. The distribution of iridoid glucosides in the Scrophulariaceae is discussed.

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Posted on 22 December 2014 | 8:33 am


Interplays between the cell wall and phytohormones in interaction between plants and necrotrophic pathogens

Publication date: Available online 9 December 2014
Source:Phytochemistry

Author(s): Majse Nafisi , Lorenzo Fimognari , Yumiko Sakuragi

The plant cell wall surrounds every cell in plants. During microbial infection, the cell wall provides a dynamic interface for interaction with necrotrophic phytopathogens as a rich source of carbohydrates for the growth of pathogens, as a physical barrier restricting the progression of the pathogens, and as an integrity sensory system that can activate intracellular signaling cascades and ultimately lead to a multitude of inducible host defense responses. Studies over the last decade have provided evidence of interplays between the cell wall and phytohormone signaling. This review summarizes the current state of knowledge about the cell wall-phytohormone interplays, with the focus on auxin, cytokinin, brassinosteroids, and abscisic acid, and discuss how they impact the outcome of plant–necrotrophic pathogen interaction.

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Highlights

This review summarizes the recent progress in understanding the interplay between cell wall and phytohormone signaling and how it impacts the ability of plants to defense themselves against necrotrophic phytopathogens.





Posted on 22 December 2014 | 8:33 am


Isolation and identification of 4-?-rhamnosyloxy benzyl glucosinolate in Noccaea caerulescens showing intraspecific variation

Publication date: Available online 4 December 2014
Source:Phytochemistry

Author(s): Rob M. de Graaf , Sebastian Krosse , Ad E.M. Swolfs , Esra te Brinke , Nadine Prill , Roosa Leimu , Peter M. van Galen , Yanli Wang , Mark G.M. Aarts , Nicole M. van Dam

Glucosinolates are secondary plant compounds typically found in members of the Brassicaceae and a few other plant families. Usually each plant species contains a specific subset of the ?130 different glucosinolates identified to date. However, intraspecific variation in glucosinolate profiles is commonly found. Sinalbin (4-hydroxybenzyl glucosinolate) so far has been identified as the main glucosinolate of the heavy metal accumulating plant species Noccaea caerulescens (Brassicaceae). However, a screening of 13 N. caerulescens populations revealed that in 10 populations a structurally related glucosinolate was found as the major component. Based on nuclear magnetic resonance (NMR) and mass spectrometry analyses of the intact glucosinolate as well as of the products formed after enzymatic conversion by sulfatase or myrosinase, this compound was identified as 4-?-rhamnosyloxy benzyl glucosinolate (glucomoringin). So far, glucomoringin had only been reported as the main glucosinolate of Moringa spp. (Moringaceae) which are tropical tree species. There was no apparent relation between the level of soil pollution at the location of origin, and the presence of glucomoringin. The isothiocyanate that is formed after conversion of glucomoringin is a potent antimicrobial and antitumor agent. It has yet to be established whether glucomoringin or its breakdown product have an added benefit to the plant in its natural habitat.

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Posted on 22 December 2014 | 8:33 am


Isoflavones with neuroprotective activities from fruits of Cudrania tricuspidata

Publication date: Available online 6 December 2014
Source:Phytochemistry

Author(s): Nguyen Tuan Hiep , Jaeyoung Kwon , Dong-Woo Kim , Bang Yeon Hwang , Hak-Ju Lee , Woongchon Mar , Dongho Lee

Ten isoflavones, cudraisoflavones B–K (110), together with 27 known isoflavones, were isolated from the EtOAc soluble extract of fruits of Cudrania tricuspidata. The structures of compounds 110 were elucidated on the basis of MS and NMR spectroscopic data, including 2D NMR experiments. Compounds 79 and three known (1113) compounds showed neuroprotective activity against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells, with EC 50 values of 0.5–9.2?M.

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Posted on 22 December 2014 | 8:33 am


Triterpenoid glycosides from the leaves of Meliosma henryi

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Abdulmagid Alabdul Magid , Hamid Morjani , Dominique Harakat , Claudie Madoulet , Vincent Dumontet , Catherine Lavaud

Seven triterpenoid glycosides, named meliosmosides A–G, were isolated from the leaves of Meliosma henryi Diels (Sabiaceae). Their structures were elucidated by different spectroscopic methods including 1D and 2D NMR experiments as well as HRESIMS analysis. Isolated compounds were evaluated for their cytotoxic activity against KB cell line.

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Posted on 22 December 2014 | 8:33 am


Structures of eremophilane-type sesquiterpene glucosides, alticolosides A–G, from the Far Eastern endemic Ligularia alticola Worosch

Publication date: Available online 3 December 2014
Source:Phytochemistry

Author(s): Alexandra S. Silchenko , Anatoly I. Kalinovsky , Ludmila P. Ponomarenko , Sergey A. Avilov , Pelageya V. Andryjaschenko , Pavel S. Dmitrenok , Peter G. Gorovoy , Natalia Yu. Kim , Valentin A. Stonik

Seven eremophilane-type sesquiterpene glucosides, alticolosides A–G, have been isolated from aerial parts of the endemic Far Eastern species Ligularia alticola Worosch. (Family Asteraceae) along with two known compounds, monoterpenoid glycoside (4S)-?-terpineol 8-O-?-d-glucopyranoside and norditerpenoid glycoside 7(8)-dihydro-?-ionone 3-O-?-d-glucopyranoside. Alticoloside D was identified with the earlier known 8-O-(?-d-glucopyranosyl)-2-oxo-eremophila-1(10),8,11-triene, but the stereostructure of the latter was revised on the basis of ROESY and CD data. All the glycosides are derivatives of new eremophilane-type aglycones, differing from known eremophilanes in details of planar and/or stereo structures except for the aglycone of alticoloside E.

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Posted on 22 December 2014 | 8:33 am


Plastochromanol-8: Fifty years of research

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Graphical Contents List

Publication date: December 2014
Source:Phytochemistry, Volume 108









Posted on 22 December 2014 | 8:33 am


Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Alessio Cimmino , Mónica Fernández-Aparicio , Fabiana Avolio , Koichi Yoneyama , Diego Rubiales , Antonio Evidente

Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and mainly restricted to O. cumana.

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Profiling of secondary metabolites in root exudates of Arabidopsis thaliana

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Identification of odorants in frankincense (Boswellia sacra Flueck.) by aroma extract dilution analysis and two-dimensional gas chromatography–mass spectrometry/olfactometry

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Johannes Niebler , Andrea Buettner

Frankincense has been known, traded and used throughout the ages for its exceptional aroma properties, and is still commonly used in both secular and religious settings to convey a pleasant odor. Surprisingly, the odoriferous principle(s) underlying its unique odor profile have never been published. In this study, resin samples of Boswellia sacra Flueck. from both Somalia and Oman were investigated by aroma extract dilution analysis. In a comprehensive, odor-activity guided approach both chemo-analytical and human-sensory parameters were used to identify odor active constituents of the volatile fraction of B. sacra. Among the key odorants found were ?-pinene, ?-myrcene, linalool, p-cresol and two unidentified sesquiterpenoids. Overall, a total of 23 odorants were detected and analyzed by gas chromatography–olfactometry and heart-cut two-dimensional gas chromatography–mass spectrometry/olfactometry. The majority of the identified odorant compounds were oxygenated monoterpenes, along with some relevant mono- and sesquiterpenes and only one diterpenoid substance. Several of these compounds were reported here for the first time as odorous constituents in B. sacra. Identifying bioactive compounds might support a better understanding with regard to the potential benefits of frankincense, for example in aromatherapy or ecclesial settings.

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Glycosidase inhibitors from the roots of Glyphaea brevis

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Diane Patricia Apie Gossan , Abdulmagid Alabdul Magid , Philomène Akoua Kouassi-Yao , Jean-Bernard Behr , Antoine Coffy Ahibo , Léon Atoutou Djakouré , Dominique Harakat , Laurence Voutquenne-Nazabadioko

Ten phenylalkyl-substituted iminosugars (110) and a cinnamic acid derived glucoside (11) were isolated from the roots of Glyphaea brevis (Malvaceae). Their structures were elucidated by 1D and 2D NMR analysis, as well as by HR-ESIMS. Compounds 110 retain an unprecedented structure composed of an iminosugar-like core identified as 1-deoxyfuconojirimycin in glyphaeaside A1–A4 (1, 2, 5, 6), 1-deoxygalactonojirimycin in glyphaeaside B1–B5 (3, 4, 79) or 1-deoxynojirimycin in glyphaeaside C (10), substituted by a ?-d-glucopyranose in compounds 2, 4, 6 and 9. These compounds feature a di-, tri- or tetra-hydroxylated nine-carbon chain at the pseudo-anomeric position, substituted by a terminal phenyl group. All alkyl C-iminosugars displayed potent and selective inhibition towards ?-glucosidase with IC50 values ranging from 0.15 to 68?M. Compound 10 with an 1-deoxynojirimycin backbone was the most active and was found to act as a competitive inhibitor with Ki =31nM, therefore emerging as one of the most potent inhibitor of ?-glucosidase reported to date. Inhibition of ?-mannosidase was observed with compounds 1, 3, 7 and 10, but only weak inhibition could be detected with the alkyl-C-iminosugars on the other tested glycosidases (?-glucosidase, ?-fucosidase, ?- and ?-galactosidase).

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Isolation and identification of an allelopathic phenylethylamine in rice

Publication date: December 2014
Source:Phytochemistry, Volume 108

Author(s): Ho Le Thi , Chung-Ho Lin , Reid J. Smeda , Nathan D. Leigh , Wei G. Wycoff , Felix B. Fritschi

Allelopathy is the process whereby an organic chemical (allelochemical) released from one plant influences the growth and development of other plants. Allelochemicals produced by specific rice (Oryza sativa L.) cultivars have potential to manage barnyard grass (Echinochloa crus-galli L.), a major yield-limiting weed species in rice production systems in Asia and North America. In this study, isolation and identification of an allelopathic compound, N-trans-cinnamoyltyramine (NTCT), in a Vietnamese rice cultivar ‘OM 5930’ was accomplished through bioassay-guided purification using reversed-phase liquid chromatography coupled with spectroscopic techniques, including tandem mass spectrometry, high resolution mass spectrometry, as well as one-dimensional and two-dimensional 1H NMR and 13C NMR spectroscopy. The identified compound, NTCT is considered a ?-phenylethylamine. NTCT inhibited root and hypocotyl growth of cress (Lepidium sativum L.), barnyard grass and red sprangletop (Leptochloa chinensis L. Nees) at concentrations as low as 0.24?M. The ED50 (concentration required for 50% inhibition) of NTCT on barnyard grass root and hypocotyl elongation were 1.35 and 1.85?M, respectively. Results further demonstrated that mortality of barnyard grass and red sprangletop seedlings was >80% at a concentration of 2.4?M of NTCT. By 20days after transplanting, 0.425nmol of NTCT per OM 5930 rice seedling was released into the culture solution. With concentrations of 42?gg?1 fresh weight, production of NTCT in intact rice plants can be considered high. These findings suggest that developing plants of Vietnamese rice cultivar OM 5930 release NTCT and may be utilized to suppress barnyard grass in rice fields. The potency of NTCT may encourage development of this compound as a bio-herbicide.

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Posted on 22 December 2014 | 8:33 am


Indole alkaloids from the Marquesan plant Rauvolfia nukuhivensis and their effects on ion channels

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Nicolas J. Martin , Sara F. Ferreiro , Florent Barbault , Mael Nicolas , Gaël Lecellier , Christian Paetz , Marc Gaysinski , Eva Alonso , Olivier P. Thomas , Luis M. Botana , Phila Raharivelomanana

In addition to the already reported nukuhivensiums 1 and 2, 11 indole alkaloids were isolated from the bark of the plant Rauvolfia nukuhivensis, growing in the Marquesas archipelago. The known sandwicine (3), isosandwicine (4), spegatrine (8), lochneram (9), flavopereirine (13) have been found in this plant together with the norsandwicine (5), isonorsandwicine (6), N b-methylisosandwicine (7), 10-methoxypanarine (10), nortueiaoine (11), tueiaoine (12). The structure elucidation was performed on the basis of a deep exploration of the NMR and HRESIMS data as well as comparison with literature data for similar compounds. Norsandwicine, 10-methoxypanarine, tueiaoine, and more importantly nukuhivensiums, were shown to significantly induce a reduction of IKr amplitude (HERG current). Molecular modelling through docking was performed in order to illustrate this result.

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Natural daucane esters induces apoptosis in leukaemic cells through ROS production

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am


Hispidacine, an unusual 8,4?-oxyneolignan-alkaloid with vasorelaxant activity, and hispiloscine, an antiproliferative phenanthroindolizidine alkaloid, from Ficus hispida Linn.

Publication date: January 2015
Source:Phytochemistry, Volume 109

Author(s): Veronica Alicia Yap , Bi-Juin Loong , Kang-Nee Ting , Sandy Hwei-San Loh , Kien-Thai Yong , Yun-Yee Low , Toh-Seok Kam , Kuan-Hon Lim

Hispidacine, an 8,4?-oxyneolignan featuring incorporation of an unusual 2-hydroxyethylamine moiety at C-7, and hispiloscine, a phenanthroindolizidine alkaloid, were isolated from the stem-bark and leaves of the Malaysian Ficus hispida Linn. Their structures were established by spectroscopic analysis. Hispidacine induced a moderate vasorelaxant activity in rat isolated aorta, while hispiloscine showed appreciable antiproliferative activities against MDA-MB-231, MCF-7, A549, HCT-116 and MRC-5 cell lines.

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Posted on 22 December 2014 | 8:33 am


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

Publication date: December 2014
Source:Phytochemistry, Volume 108

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 22 December 2014 | 8:33 am





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