Current research reports and chronological list of recent articles.
Phytochemistry is the international scientific journal of pure and applied plant chemistry, plant biochemistry and molecular biology. It is also a is a primary source for papers dealing with plant secondary compounds, especially with regard to their biosynthesis and diverse properties.
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Publication date: Available online 4 February 2016 Source:Phytochemistry Author(s): Manasi R. Hardikar, Mokshada E. Varma, Anjali A. Kulkarni, Prasad P. Kulkarni, Bimba N. Joshi We have reported earlier, an orally active insulin-like protein (ILP) from Costus igneus having potent hypoglycemic property in STZ-induced diabetic Swiss mice. The blood glucose level was reduced significantly within two hours after feeding ILP orally in an oral glucose tolerance test. The present study elucidates the mechanism underlying the hypoglycemic action of ILP. Mechanism of action of ILP was studied in differentiated L6 myotubes. 2-NBDG uptake stimulated by ILP was studied in differentiated L6 myotubes under normoglycemic, hyperglycemic and induced insulin resistant conditions. ILP treatment significantly increased 2-NBDG uptake in differentiated L6 myotubes. The levels of insulin signaling molecules IRS-1 and GLUT-4 were assessed in ILP treated L6 myotubes by immunoblot analysis of cytoplasmic and plasma membrane fractions respectively. Immunoblot analysis revealed an increase in cytoplasmic IRS-1 with a concomitant increase in GLUT-4 translocation to the plasma membrane in a time dependent manner. Toxicity studies of ILP were performed on normal as well as diabetic Swiss albino mice. ILP did not show any toxicity in the acute and sub-chronic toxicity studies in normal as well as diabetic Swiss albino mice. Mass spectrometry was carried out to identify ILP. MALDI TOF/TOF MS analysis of ILP revealed sequence homology with the predicted protein from Physcomitrella patens. Our study reveals that ILP acts via insulin signaling pathway and can be used as oral insulin mimetic.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Siti Aisyah, Jean-Paul Vincken, Silvia Andini, Zahara Mardiah, Harry Gruppen The effects of germination and elicitation on (iso)flavonoid composition of extracts from three edible lupine species (Lupinus luteus, Lupinus albus, Lupinus angustifolius) were determined by RP-UHPLC–MSn. The total (iso)flavonoid content of lupine increased over 10-fold upon germination, with the total content and composition of isoflavonoids more affected than those of flavonoids. Glycosylated isoflavones were the most predominant compounds found in lupine seedlings. Lesser amounts of isoflavone aglycones, including prenylated ones, were also accumulated. Elicitation with Rhizopus oryzae, in addition to germination, raised the content of isoflavonoids further: the total content of 2′-hydroxygenistein derivatives was increased considerably, without increasing that of genistein derivatives. Elicitation by fungus triggered prenylation of isoflavonoids, especially of the 2′-hydroxygenistein derivatives. The preferred positions of prenylation differed among the three lupine species. The change in isoflavone composition increased the agonistic activity of the extracts towards the human estrogen receptors, whereas no antagonistic activity was observed.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Yasodha Sivasothy, Kong Yong Loo, Kok Hoong Leong, Marc Litaudon, Khalijah Awang A dimeric acylphenol and a potent α-glucosidase inhibitor, giganteone D (IC50 5.05μM), was isolated and characterized from the bark of Myristica cinnamomea King. The bark also yielded an acylphenol with an unprecedented skeleton for which the name cinnamomeone A (IC50 358.80μM) was proposed. Their structures were established by means of NMR and MS spectrometric analyses. The Lineweaver–Burk plot of giganteone D indicated that it was a mixed-type inhibitor. This is the first report on the α-glucosidase inhibiting potential of acylphenols.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Hana Vylíčilová, Alexandra Husičková, Lukáš Spíchal, Josef Srovnal, Karel Doležal, Ondřej Plíhal, Lucie Plíhalová Cytokinins are plant hormones with biological functions ranging from coordination of plant growth and development to the regulation of senescence. A series of 2-chloro-N6-(halogenobenzylamino)purine ribosides was prepared and tested for cytokinin activity in detached wheat leaf senescence, tobacco callus and Amaranthus bioassays. The synthetic compounds showed significant activity, especially in delaying senescence in detached wheat leaves. They were also tested in bacterial receptor bioassays using both monocot and dicot members of the cytokinin receptor family. Most of the derivatives did not trigger cytokinin signaling via the AHK3 and AHK4 receptors from Arabidopsis thaliana in the bacterial assay, but some of them specifically activated the ZmHK1 receptor from Zea mays and were also more active than the aromatic cytokinin BAP in an ARR5::GUS cytokinin bioassay using transgenic Arabidopsis plants. Whole transcript expression analysis was performed using an Arabidopsis model to gather information about the reprogramming of gene transcription when senescent leaves were treated with selected C2-substituted aromatic cytokinin ribosides. Genome-wide expression profiling revealed that the synthetic halogenated derivatives induced the expression of genes related to cytokinin signaling and metabolism. They also prompted both up- and down-regulation of a unique combination of genes coding for components of the photosystem II (PSII) reaction center, light-harvesting complex II (LHCII), and the oxygen-evolving complex, as well as several stress factors responsible for regulating photosynthesis and chlorophyll degradation. Chlorophyll content and fluorescence analyses demonstrated that treatment with the halogenated derivatives increased the efficiency of PSII photochemistry and the abundance of LHCII relative to DMSO- and BAP-treated controls. These findings demonstrate that it is possible to manipulate and fine-tune leaf longevity using synthetic aromatic cytokinin analogs.
Publication date: Available online 12 February 2016 Source:Phytochemistry Author(s): Christian Zidorn Seagrasses are the only higher plants living in fully marine environments; they play a significant role in coastal ecosystems. Seagrasses inhabit the coastal shelves of all continents except Antarctica and can grow in depths of up to 90m. Because of their eminent ecological importance, innumerous studies have been dedicated to seagrasses and their ecology. However, the phytochemistry has not been equally well investigated yet and many of the existing studies in chemical ecology are only investigating the chemistry at the level of compound classes, e.g. phenolics, and not at the level of chemically defined metabolites. In the present review, the existing literature on secondary metabolites of seagrasses, their known source seagrasses, their bioactivity, and ecological function are compiled and critically assessed. Moreover, research gaps are highlighted and avenues for future research are discussed.Currently, a total of 154 chemically defined natural products have been reported from the about 70 seagrass species known worldwide. Compounds reported include simple phenols derivatives (four compounds), phenylmethane derivatives (14 compounds), phenylethane derivatives (four compounds), phenylpropane derivatives including their esters and dimers (20 compounds), chalkones (four compounds), flavonoids including catechins (57 compounds), phenylheptanoids (four compounds), one monoterpene derivative, one sesquiterpene, diterpenoids (13 compounds), steroids (31 compounds), and one alkaloid.Most of the existing bioactivity studies of seagrass metabolites and extracts have been directed to potential cytotoxic, antimicrobial, or antimacrofouling activity. Antimicrobial studies have been performed towards panels of both human pathogens and ecologically relevant pathogens. In the antimacrofouling studies, investigations of the potential of zosteric acid from the genus Zostera are the most numerous and have yielded so far the most interesting results.Studies on the chemical ecology of seagrasses often have been focused on variation in phenolic compounds and include but are not limited to studies on variation due to abiotic factors, seasonal variation, variation in response to grazing by fish or sea urchins, or following microbial attack.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Hoang Linh Mai, Philippe Grellier, Elise Prost, Pascale Lemoine, Cyril Poullain, Vincent Dumontet, Brigitte Deguin, Thi Bach Hue Vo, Sylvie Michel, Raphaël Grougnet A cycloartane gardurvilleic acid, three 3,4-seco-cycloartanes securvienol, secodienurvilleic acid, securvitriol, a 3,4;9,10-seco-cycloartane gardheptlactone, two dammaranes urvilone, urvilol, along with eight known cycloartanes and 3,4-seco-cycloartanes and four known dammaranes have been isolated from the bud exudate of Gardenia urvillei, an endemic tree to the New Caledonian dry forest. Two other dammarane derivatives have been obtained by semisynthesis. The structures of the original compounds were determined by spectroscopic methods and chemical correlations. In association with previously published data, the description of oxidized side-chains in position 17 are now available for two couples of diastereoisomers. Evaluation of anti-parasite activity and cytotoxicity has shown noticeable results for some of the isolated triterpenes.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Ingrid Lenoir, Joël Fontaine, Anissa Lounès-Hadj Sahraoui The majority of plants live in close collaboration with a diversity of soil organisms among which arbuscular mycorrhizal fungi (AMF) play an essential role. Mycorrhizal symbioses contribute to plant growth and plant protection against various environmental stresses. Whereas the resistance mechanisms induced in mycorrhizal plants after exposure to abiotic stresses, such as drought, salinity and pollution, are well documented, the knowledge about the stress tolerance mechanisms implemented by the AMF themselves is limited. This review provides an overview of the impacts of various abiotic stresses (pollution, salinity, drought, extreme temperatures, CO2, calcareous, acidity) on biodiversity, abundance and development of AMF and examines the morphological, biochemical and molecular mechanisms implemented by AMF to survive in the presence of these stresses.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Gilles Curien, Cécile Giustini, Jean-Luc Montillet, Sarah Mas-y-Mas, David Cobessi, Jean-Luc Ferrer, Michel Matringe, Alexander Grechkin, Norbert Rolland Under oxidative stress conditions the lipid constituents of cells can undergo oxidation whose frequent consequence is the production of highly reactive α,β-unsaturated carbonyls. These molecules are toxic because they can add to biomolecules (such as proteins and nucleic acids) and several enzyme activities cooperate to eliminate these reactive electrophile species. CeQORH (chloroplast envelope Quinone Oxidoreductase Homolog, At4g13010) is associated with the inner membrane of the chloroplast envelope and imported into the organelle by an alternative import pathway. In the present study, we show that the recombinant ceQORH exhibits the activity of a NADPH-dependent α,β-unsaturated oxoene reductase reducing the double bond of medium-chain (C⩾9) to long-chain (18 carbon atoms) reactive electrophile species deriving from poly-unsaturated fatty acid peroxides. The best substrates of ceQORH are 13-lipoxygenase-derived γ-ketols. γ-Ketols are spontaneously produced in the chloroplast from the unstable allene oxide formed in the biochemical pathway leading to 12-oxo-phytodienoic acid, a precursor of the defense hormone jasmonate. In chloroplasts, ceQORH could detoxify 13-lipoxygenase-derived γ-ketols at their production sites in the membranes. This finding opens new routes toward the understanding of γ-ketols role and detoxification.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Luciana Georgescu, Michalis K. Stefanakis, Stella Kokkini, Haralambos E. Katerinopoulos, Stergios A. Pirintsos The genus Phlomis is represented in the island of Crete (Greece, Eastern Mediterranean) by three species Phlomis cretica C. Presl., Phlomis fruticosa L., the island endemic Phlomis lanata Willd. and three hybrids Phlomis x cytherea Rech.f. (P. cretica x P. fruticosa), Phlomis x commixta Rech.f. (P. cretica x P. lanata) and Phlomis x sieberi Vierh. (P. fruticosa x P. lanata). This work describes (a) the profile of hybrids and parental species concerning their volatile compounds, (b) the suitability of ribosomal nuclear (ITS region), chloroplast (trnH-psbA), and AFLP markers to identify hybrids and (c) their competence to characterize the different chemotypes of both hybrids and their parental species. The cluster analysis and PCA constructed from chemical data (volatile oils) suggest that there are three groups of taxa. Group IA includes P. cretica and P. fruticosa, group IB includes P. x cytherea, whereas group II consists of P. x commixta, P. x sieberi and P. lanata. Volatile compounds detected only in the hybrids P. x sieberi and P. x commixta correspond to the 3% of the total compounds, value that is much higher in P. x cytherea (21%). Neighbor-joining, statistical parsimony analysis and the observations drawn from ribotypes spectrum of ITS markers divided Phlomis species in two groups, P. lanata and the complex P. cretica/P. fruticosa. In contrast to the ITS region, the plastid DNA marker follows a geographically related pattern. Neighbor-Net, PCA and Bayesian assignment analysis performed for AFLP markers separated the genotypes into three groups corresponding to populations of P. cretica, P. fruticosa, and P. lanata, respectively, while populations of P. x commixta, P. x cytherea, and P. x sieberi presented admixed ancestry. Most of the P. x cytherea samples were identified as F1 hybrids by Bayesian assignment test, while those of P. x commixta and P. x sieberi were identified as F2 hybrids. Overall, high chemical differentiation is revealed in one of the three hybrids, which is likely related with niche variation. Moreover, molecular markers show potential to identify Phlomis taxa.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Mario Wibowo, Vilailak Prachyawarakorn, Thammarat Aree, Chulabhorn Mahidol, Somsak Ruchirawat, Prasat Kittakoop Twenty previously unknown compounds and two known metabolites, merulin A and merulin D, were isolated from the endophytic fungus Pseudolagarobasidium acaciicola, which was isolated from a mangrove tree, Bruguiera gymnorrhiza. Structures of the 20 compounds were elucidated by analysis of spectroscopic data. The absolute configuration of seven of these compounds was addressed by a single crystal X-ray analysis using CuKα radiation and an estimate of the Flack parameter. Three compounds also possessed a tricyclic ring system. Terpene endoperoxides isolated exhibited cytotoxic activity, while those without an endoperoxide moiety did not show activity. The endoperoxide moiety of sesquiterpenes has significant impact on cytotoxic activity, and thus is an important functionality for cytotoxicity. One terpene endoperoxide displayed potent cytotoxic activity (IC50 0.28μM), and selectively exhibited activity against the HL-60 cell line.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Daniel D. McClosky, Bo Wang, Gong Chen, Charles T. Anderson Plant cell walls are dynamic structures whose polysaccharide components are rearranged and recycled during growth and morphogenesis. Covalent fluorescent tagging of these polysaccharides following a metabolic labeling approach can help elucidate these changes. Herein reported are the synthesis and seedling-incorporation of a plant polysaccharide chemical reporter, 6-deoxy-alkynyl glucose (6dAG), that is modeled on d-glucose. Whereas fucose-alkyne, a previously reported chemical reporter for pectin, incorporates diffusely throughout growing cell walls, 6dAG incorporated specifically into root hair tips. This incorporation occurs in a time- and concentration-dependent manner. 6dAG exposure both induces and colocalizes with callose deposition in this tissue, and arrests both root hair and root growth. These results show that plants can incorporate an additional alkynyl-modified sugar analog into their metabolism, and into a discrete subcellular location.
Publication date: Available online 4 February 2016 Source:Phytochemistry Author(s): Eugenio Alcalde, Humberto R. Medina, M. Mar Herrador, Alejandro F. Barrero, Enrique Cerdá-Olmedo The oxidative cleavage of β-carotene in the Mucorales produces three fragments of 18, 15, and 7 carbons, respective heads of three families of apocarotenoids: the methylhexanoids, the trisporoids, and the cyclofarnesoids (named after their 1,6-cyclofarnesane skeleton). The apocarotenoids are easily recognized because they are absent in white mutants unable to produce β-carotene. In cultures of Phycomyces blakesleeanus we detected thirty-two apocarotenoids by LC, UV absorbance, and MS. With additional IR and NMR we identified two methylhexanoids and the eight most abundant cyclofarnesoids. Four of them were previously-unknown natural compounds, including 4-dihydrocyclofarnesine S, the most abundant cyclofarnesoid in young cultures. We arranged the apocarotenoids of the Mucorales in a scheme that helps classifying and naming them and suggests possible metabolites and biosynthetic pathways. We propose specific biosynthetic pathways for cyclofarnesoids and methylhexanoids based on structural comparisons, the time course of appearance of individual compounds, and the bioconversion of β-apo-12-carotenol, an early precursor, to three more oxygenated cyclofarnesoids by the white mutants. Some of the reactions occur spontaneously in the increasingly acidic culture media. Mating increased the contents of methylhexanoids and cyclofarnesoids by ca. threefold in young cultures and ca. twelvefold in old ones (five days); cyclofarnesine S, the most abundant cyclofarnesoid in old cultures, increased over one hundredfold. We found no differences between the sexes and no activity as sexual pheromones, but we suggest that methylhexanoids and cyclofarnesoids could mediate species-specific physiology and behavior.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Robert Stipanovic, Lorraine Puckhaber, James Frelichowski, Jesus Esquivel, John Westbrook, Mike O’Neil, Alois Bell, Michael Dowd, Kater Hake, Sara Duke The report that the cotton leaf perforator, Bucculatrix thurberiella, is one of the few insect herbivores to attack Gossypium thurberi prompted an investigation of the terpenoids present in the leaves of this wild species of cotton. Members of Gossypium produce subepidermal pigment glands in their leaves that contain the dimeric sesquiterpenoid gossypol as well as other biosynthetically related terpenoids. In addition to gossypol, a previously unknown dimeric sesquiterpenoid, gossypolhemiquinone (GHQ), was identified in trace amounts in G. thurberi, a member of the D genome. Other members of the D genome of Gossypium were subsequently found to contain this compound, but GHQ was not detected in commercial cotton cultivars. When fed to Helicoverpa zea in an artificial diet, GHQ delayed days-to-pupation, reduced pupal weights, and survival to adulthood to a lesser or equal extent than gossypol in comparison to the control diet. However, GHQ had a synergistic effect on survival and days-to-pupation when combined with gossypol at the highest dosage tested (0.18%; 15.5:84.5 GHQ:gossypol). Because gossypol exhibits anti-cancer activity, GHQ was also evaluated for its anti-cancer activity against the National Cancer Institute’s 60-Human Tumor Cell Line Screen. Significant inhibitory activity against most of these cell lines was not observed, but the results may offer some promise against leukemia cancer cell lines.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Philip C. Stevenson, Paul W.C. Green, Nigel C. Veitch, Iain W. Farrell, Paul Kusolwa, Steven R. Belmain Zanha africana (Radlk.) Exell (Sapindaceae) root bark is used by farmers throughout sub-Saharan Africa to protect stored grain from bruchid beetles, such as Callosobruchus maculatus. Chloroform, methanol and water extracts of Z. africana root bark inhibited oviposition and caused significantly higher mortality of C. maculatus at a rate of application equivalent to that applied by farmers compared to control insects. The chloroform extract contained nor-hopanes rarely found in plants of which seven were isolated, one of which was previously known. Two of the most abundant nor-hopanes 3β,6β-dihydroxy-7β-[(4-hydroxybenzoyl)oxy]-21αH-24-norhopa-4(23),22(29)-diene and 3β,6β-dihydroxy-7β-[(4-hydroxybenzoyl)oxy]-24-norhopa-4(23),17(21)-diene were toxic to and reduced oviposition of C. maculatus in a dose dependent manner. Z. africana root bark is rich in insecticidal compounds that account for its effective use by smallholder farmers as an alternative to conventional insecticides.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Pengfei Sun, Cristian Leeson, Xiaoduo Zhi, Fenfei Leng, Richard H. Pierce, Michael S. Henry, Kathleen S. Rein Epoxide hydrolases (EH, EC 126.96.36.199) have been proposed to be key enzymes in the biosynthesis of polyether (PE) ladder compounds such as the brevetoxins which are produced by the dinoflagellate Karenia brevis. These enzymes have the potential to catalyze kinetically disfavored endo-tet cyclization reactions. Data mining of K. brevis transcriptome libraries revealed two classes of epoxide hydrolases: microsomal and leukotriene A4 (LTA4) hydrolases. A microsomal EH was cloned and expressed for characterization. The enzyme is a monomeric protein with molecular weight 44kDa. Kinetic parameters were evaluated using a variety of epoxide substrates to assess substrate selectivity and enantioselectivity, as well as its potential to catalyze the critical endo-tet cyclization of epoxy alcohols. Monitoring of EH activity in high and low toxin producing cultures of K. brevis over a three week period showed consistently higher activity in the high toxin producing culture implicating the involvement of one or more EH in brevetoxin biosynthesis.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Kristýna Floková, Kirstin Feussner, Cornelia Herrfurth, Otto Miersch, Václav Mik, Danuše Tarkowská, Miroslav Strnad, Ivo Feussner, Claus Wasternack, Ondřej Novák Jasmonates (JAs) are plant hormones that integrate external stress stimuli with physiological responses. (+)-7-iso-JA-L-Ile is the natural JA ligand of COI1, a component of a known JA receptor. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-(+)-OPDA) has been reported to act independently of COI1 as an essential signal in several stress-induced and developmental processes. Wound-induced increases in the endogenous levels of JA/JA-Ile are accompanied by two to tenfold increases in the concentration of OPDA, but its means of perception and metabolism are unknown. To screen for putative OPDA metabolites, vegetative tissues of flowering Arabidopsis thaliana were extracted with 25% aqueous methanol (v/v), purified by single-step reversed-phase polymer-based solid-phase extraction, and analyzed by high throughput mass spectrometry. This enabled the detection and quantitation of a low abundant OPDA analog of the biologically active (+)-7-iso-JA-L-Ile in plant tissue samples. Levels of the newly identified compound and the related phytohormones JA, JA-Ile and cis-(+)-OPDA were monitored in wounded leaves of flowering Arabidopsis lines (Col-0 and Ws) and compared to the levels observed in Arabidopsis mutants deficient in the biosynthesis of JA (dde2-2, opr3) and JA-Ile (jar1). The observed cis-(+)-OPDA-Ile levels varied widely, raising questions concerning its role in Arabidopsis stress responses.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Ji-Hyun Youn, Min Kyun Kim, Eun-Ji Kim, Seung-Hyun Son, Ji Eun Lee, Mun-Seok Jang, Tae-Wuk Kim, Seong-Ki Kim Homeostasis of brassinosteroids (BRs) maintained by the balance between their biosynthesis and inactivation is important to coordinate the diverse physiological and developmental responses of plants. Although BR signaling regulates the endogenous levels of BRs via negative feedback regulation, it remains largely unknown how the biosynthesis and inactivation of BR are triggered. BAS1 encodes CYP734A1, which inactivates the biologically active BRs via C-26 hydroxylation and is down-regulated by a BR-responsive transcription factor, BZR1. Here it is demonstrated that the expression of the BAS1 gene is regulated by auxin response factors (ARFs) in Arabidopsis thaliana. Two successive E-box motifs on the BAS1 promoter function as BZR1 binding sites and are essential for BR-regulated BAS1 expression. The expression of BAS1 is increased in the arf7 and arf7arf19 mutants. The endogenous level of bioactive BR, castasterone, is greatly decreased in those mutants. ARF7 can bind to the E-box motifs of the BAS1 promoter where BZR1 binds, suggesting that ARF7 and BZR1 mutually compete for the same cis-element of the BAS1 promoter. Additionally, ARF7 directly interacts with BZR1, which inhibits their DNA binding activities and regulation of BAS1 expression. In conclusion, auxin signaling via ARF7 directly modulates the expression of BAS1 by competition with BZR1, thereby increasing the level of castasterone and promoting growth and development in A. thaliana.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Oxana Babova, Andrea Occhipinti, Massimo E. Maffei Green coffee beans of Coffea arabica and Coffea canephora accessions from different geographical origin (Brazil, Colombia, Ethiopia, Honduras, Kenya, Mexico, Peru, Uganda and Vietnam) were extracted and the extracts analyzed by HPLC–ESI-MS/MS for the identification and quantification of chlorogenic acids and caffeine content. Principal component and cluster analyses were used to identify chemical patterns separating the different species and accessions based on their geographical origin. C. canephora showed always a higher caffeine content with respect to C. arabica, whereas the C. arabica accessions from Kenya showed a higher chlorogenic acids and a lower caffeine content. The antioxidant capacity of green coffee extracts was assayed by the reducing power and DPPH assays. The antioxidant capacity correlated with the chlorogenic acids content. The results show that the C. arabica from Kenya possesses the highest chlorogenic acids/caffeine ratio and, among the C. arabica accessions, the highest antioxidant capacity. Therefore, the C. arabica from Kenya is the most suitable green coffee source for nutraceutical applications because of its high antioxidant capacity and low caffeine content.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Dimitre A. Ivanov, Jorge R.C. Georgakopoulos, Mark A. Bernards Ginsenosides produced by ginseng (Panax quinquefolius L.) are mildly fungitoxic saponins; however, exposure of the ginseng root pathogen Pythium irregulare Buisman to ginsenosides enhances its growth in a dose dependent manner, leading to speculation that ginsenosides may function as chemoattractants and/or growth regulators in the context of the ginseng – P. irregulare pathosystem. In the present work, it was demonstrated that the treatment of ginseng plants with a relatively high dose of ginsenosides by dipping their roots into a solution of ginsenosides prior to planting results in delayed infection by P. irregulare in pot experiments, as monitored by non-invasive chlorophyll fluorescence imaging. In an attempt to determine whether this observation results from a protective effect of the ginsenosides, or from a modification of P. irregulare growth habit in response to ginsenosides present in the soil, standard in vitro disk diffusion assays were conducted. Here, exposure of P. irregulare to crude ginsenosides or pure ginsenoside Rb1, resulted in delayed hyphal progression, while enhancing aerial hyphae build-up around ginsenoside-treated disks. By contrast, assays with pure ginsenoside F2 resulted in clear zones of inhibition around treated disks. While it remains unclear whether ginsenosides act as chemoattractants for P. irregulare in vivo, the results here suggest that these saponins serve to alter the growth habit of this organism, both in vivo and in vitro.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Alexandra Chapman, Christian Lindermayr, Erich Glawischnig In Arabidopsis thaliana phytoalexin biosynthesis is tightly regulated. The camalexin biosynthetic gene CYP71B15/PAD3 is highly expressed in response to pathogens and specific abiotic triggers, while constitutive expression is very low. Based on this property we expressed artificial antimicrobial peptides under control of the CYP71B15 promoter avoiding potential toxic effects to the plant related to constitutive expression. Significant and substantial growth inhibition of Pseudomonas syringae was observed, demonstrating that expression of these peptides under control of a phytoalexin promoter is an effective approach for enhancement of resistance against bacterial pathogens.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Abdelmalek Rezgui, Anne-Claire Mitaine-Offer, Tomofumi Miyamoto, Chiaki Tanaka, Stéphanie Delemasure, Patrick Dutartre, Marie-Aleth Lacaille-Dubois Four previously undescribed and one known oleanolic acid glycosides were isolated from the roots of Weigela stelzneri, and one previously undescribed and three known hederagenin glycosides were isolated from the leaves. Their structures were elucidated mainly by 2D NMR spectroscopic analysis and mass spectrometry as 3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyloleanolic acid, 3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyloleanolic acid, 3-O-β-d-glucopyranosyl-(1→2)-[β-d-glucopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyloleanolic acid, 3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyloleanolic acid 28-O-β-d-glucopyranosyl-(1→6)-β-d-glucopyranosyl ester, and 3-O-β-d-glucopyranosyl-(1→2)-α-l-arabinopyranosylhederagenin 28-O-β-d-xylopyranosyl-(1→6)-[α-l-rhamnopyranosyl-(1→2)]-β-d-glucopyranosyl ester.The majority of the isolated compounds were evaluated for their cytotoxicity against two tumor cell lines (SW480 and EMT-6), and for their anti-inflammatory activity. The compounds 3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranosyloleanolic acid and 3-O-β-d-glucopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-β-d-xylopyranosyl-(1→4)-β-d-xylopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-β-d-xylopyranosyloleanolic acid exhibited the strongest cytotoxicity on both cancer cell lines. They revealed a 50% significant inhibitory effect of the IL-1β production by PBMCs stimulated with LPS at a concentration inducing a very low toxicity of 23% and 28%, respectively.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Ting Tang, Peile Liu, Guowei Zheng, Weiqi Li Long-term moderate heat is often experienced by plants and will become even more common in the future due to global warming. However, the responses of plants to this stress have not been characterised. In the present study, growth between Arabidopsis thaliana and its relative Arabis paniculata upon long-term exposure to moderate heat was compared. It was found that the latter was more tolerant than the former, and the patterns of physiological and biochemical responses of both plants presented two phases. The early phase involved no significant visible morphological and physiological changes. It occurred during the first third of the heat treatment and was extended when the stress was attenuated. During the later phase, the plants died or were damaged. Heat shock proteins were dramatically induced at the early phase and gradually decreased at the later phase in A. thaliana. By contrast, the levels were induced and maintained in A. paniculata. Profiling of membrane lipids found that the two plants exhibited opposite patterns of lipid remodelling at the early phase: A. paniculata synthesised phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol and showed a rapid decrease in the degree of lipid unsaturation, while A. thaliana degraded its lipids at the early phase and showed an accelerated degradation at the later phase. These biochemical adjustments during the early phase could favor the thermotolerance of A. paniculata. These results suggest that this species could thus be a model for the study of resistance to long-term moderate heat, through a strategy by which plants can adapt to long-term moderate heat.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Matthew J. Bertin, Ozlem Demirkiran, Gabriel Navarro, Nathan A. Moss, John Lee, Gregory M. Goldgof, Edgar Vigil, Elizabeth A. Winzeler, Fred A. Valeriote, William H. Gerwick Bioassay-guided fractionation of two marine cyanobacterial extracts using the H-460 human lung cancer cell line and the OVC-5 human ovarian cancer cell line led to the isolation of three related α-methoxy-β, β′-dimethyl-γ-pyrones each containing a modified alkyl chain, one of which was identified as the previously reported kalkipyrone and designated kalkipyrone A. The second compound was an analog designated kalkipyrone B. The third was identified as the recently reported yoshinone A, also isolated from a marine cyanobacterium. Kalkipyrone A and B were obtained from a field-collection of the cyanobacterium Leptolyngbya sp. from Fagasa Bay, American Samoa, while yoshinone A was isolated from a field-collection of cyanobacteria (cf. Schizothrix sp.) from Panama. One-dimensional and two-dimensional NMR experiments were used to determine the overall structures and relative configurations of the kalkipyrones, and the absolute configuration of kalkipyrone B was determined by 1H NMR analysis of diastereomeric Mosher’s esters. Kalkipyrone A showed good cytotoxicity to H-460 human lung cancer cells (EC50=0.9μM), while kalkipyrone B and yoshinone A were less active (EC50=9.0μM and >10μM, respectively). Both kalkipyrone A and B showed moderate toxicity to Saccharomyces cerevisiae ABC16-Monster strain (IC50=14.6 and 13.4μM, respectively), whereas yoshinone A was of low toxicity to this yeast strain (IC50=63.8μM).
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Timothy S. Johnson, Michael L. Schwieterman, Joo Young Kim, Keun H. Cho, David G. Clark, Thomas A. Colquhoun Hybrid Lilium (common name lily) cultivars are among the top produced domestic fresh cut flowers and potted plants in the US today. Many hybrid Lilium cultivars produce large and showy flowers that emit copious amounts of volatile molecules, which can negatively affect a consumer’s appreciation or limit use of the plant product. There are few publications focused on the biochemistry, genetics, and/or molecular regulation of floral volatile biosynthesis for Lilium cultivars. In an initial pursuit to provide breeders with molecular markers for floral volatile biosynthesis, a total of five commercially available oriental and oriental-trumpet hybrid Lilium cultivars were selected for analytical characterization of floral volatile emission. In total, 66 volatile molecules were qualified and quantitated among all cultivars. Chemical classes of identified volatiles include monoterpene hydrocarbons, monoterpene alcohols and aldehydes, phenylpropanoids, benzenoids, fatty-acid-derived, nitrogen-containing, and amino-acid-derived compounds. In general, the floral volatile profiles of the three oriental-trumpet hybrids were dominated by monoterpene hydrocarbons, monoterpene alcohols and aldehydes, while the two oriental hybrids were dominated by monoterpene alcohols and aldehydes and phenylpropanoids, respectively. Tepal tissues (two petal whirls) emitted the vast majority of total volatile molecules compared to the reproductive organs of the flowers. Tepal volatile profiles were cultivar specific with a high degree of distinction, which indicates the five cultivars chosen will provide an excellent differential genetic environment for gene discovery through comparative transcriptomics in the future. Cloning and assaying transcript accumulation from four floral volatile biosynthetic candidates provided few immediate or obvious trends with floral volatile emission.
Floral volatile characterization of five Lilium cultivars reveals specific and diverse chemical profiles, which uncovers a simple platform to perform comparative transcriptomics for volatile biosynthesis gene discovery.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Berenice Corona-Castañeda, Daniel Rosas-Ramírez, Jhon Castañeda-Gómez, Manuel Alejandro Aparicio-Cuevas, Mabel Fragoso-Serrano, Gabriela Figueroa-González, Rogelio Pereda-Miranda Recycling liquid chromatography was used for the isolation and purification of resin glycosides from the CHCl3-soluble extracts prepared using flowers of Ipomoea wolcottiana Rose var. wolcottiana. Bioassay-guided fractionation, using modulation of both antibiotic activity against multidrug-resistant strains of Gram-negative bacteria and vinblastine susceptibility in breast carcinoma cells, was used to isolate the active glycolipids as modulators of the multidrug resistance phenotype. An ester-type dimer, wolcottine I, one tetra- and three pentasaccharides, wolcottinosides I–IV, in addition to the known intrapilosin VII, were characterized by NMR spectroscopy and mass spectrometry. In vitro assays established that none of these metabolites displayed antibacterial activity (MIC>512μg/mL) against multidrug-resistant strains of Escherichia coli, and two nosocomial pathogens: Salmonella enterica serovar Typhi and Shigella flexneri; however, when tested (25μg/mL) in combination with tetracycline, kanamycin or chloramphenicol, they exerted a potentiation effect of the antibiotic susceptibility up to eightfold (64μg/mL from 512μg/mL). It was also determined that these non-cytotoxic (CI50>8.68μM) agents modulated vinblastine susceptibility at 25μg/mL in MFC-7/Vin+ cells with a reversal factor (RFMCF-7/Vin+) of 2–130 fold.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Wen-qiong Wang, Li-jiang Xuan Investigation of the hydrophobic extract of Rabdosia serra (Lamiaceae) led to the isolation of seven ent-6,7-secokaurane diterpenoids rabdosins E–K, along with twelve known ent-kaurane diterpenoids. Their structures were established by extensive spectroscopic analysis. The absolute configurations of rabdosins E, F, H and I were determined by single-crystal X-ray diffraction, with rabdosin E having a 3,20-epoxy group. These diterpenoids could be divided into two types according to their skeletons: rabdosins E–J are ent-6,20-epoxy-6,7-secokaur-1,7-olides, and rabdosin K is an ent-6,7-secokaur-7,20-olide. Cytotoxicity evaluation showed that serrin B, serrin A, isodocarpin and lushanrubescensin J exhibited weak to moderate cytotoxic activities (IC50<10μM) against two human cancer cell lines.
Seven enmein-type ent-kauranoids, named as rabdosins E–K, along with twelve known diterpenoids, were isolated from the hydrophobic extract of Rabdosia serra. Weak to moderate cytotoxic activities against two human cancer cell lines were detected.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): A. Ramsay, A.R. Williams, S.M. Thamsborg, I. Mueller-Harvey Proanthocyanidins (PA) from shea (Vitellaria paradoxa) meal were investigated by thiolytic degradation with benzyl mercaptan and the reaction products were analysed by high performance liquid chromatography–mass spectrometry. These PA were galloylated (≈40%), contained only B-type linkages and had a high proportion of prodelphinidins (>70%). The mean degree of polymerisation was 8 (i.e. average molecular size was 2384Da) and epigallocatechin gallate (EGCg) was the major flavan-3-ol subunit in PA. Shea meal also proved to be a potentially valuable source for extracting free flavan-3-ol-O-gallates, especially EGCg (575mg/kg meal), which is known for its health and anti-parasitic benefits. Proanthocyanidins were isolated and tested for bioactivity against Ascaris suum, which is an important parasite of pigs. Migration and motility tests revealed that these PA have potent activity against this parasitic nematode.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Ayaka Fujiwara, Mayuko Nishi, Shigeo Yoshida, Morifumi Hasegawa, Chieko Yasuma, Akihide Ryo, Yoshihito Suzuki Cancer stem cells (CSCs) constitute a small population of undifferentiated cells within a tumor that have the ability to self-renew and drive tumor formation, thus behaving as cancer-initiating cancer cells. Therapeutic interventions that eliminate CSCs are necessary to completely cure patients, since CSCs are a crucial source of tumor recurrence and metastasis. An induced CSC-like (iCSCL) model was recently established using induced pluripotent stem cells (iPSCs). In this study, a natural product—eucommicin A—was identified from Eucommia ulmoides leaves by screening for anti-CSC activity using the iCSCL model. Its structure was elucidated by spectroscopic methods as a quinic acid diester of 3,4,3′,4′-tetrahydroxy-β-truxinic acid. Eucommicin A exhibited selective anti-CSC activity and inhibited tumor sphere formation by iCSCL cells. The results of this study suggest that eucommicin A could serve as a lead compound in the development of drugs to abrogate the stemness and self-renewal ability of CSCs.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Wei Wei, Xiu-Wen Wu, Gai-Gai Deng, Xiu-Wei Yang The 1H NMR-guided fractionation of a cyclohexane soluble portion of the 75% ethanolic extract of the roots of Angelica dahurica cv. Hangbaizhi led to the isolation of two coumarins, namely, 5-(3″-hydroxy-3″-methylbutyl)-8-hydroxyfuranocoumarin, and isobyakangelicin hydrate-3″-ethyl ether, and ten coumarins with short- or long-chain hydrophobic groups, namely, andafocoumarins A–J. Their structures were elucidated by extensive spectroscopic analyses. The absolute configurations of the C-2″ secondary alcohols in ten of these compounds were deduced via the circular dichroism data of the in situ formed [Rh2(OCOCF3)4] complex, and oxidation reactions were utilized to determine location of the double bonds in the lipid chain of andafocoumarins H and I, respectively. The long-chain hydrophobic group of andafocoumarin J was determined by the method of chemical degradation and GC–MS analysis. It was the first time that coumarins with short- or long-chain hydrophobic groups in this plant had been comprehensively investigated. All isolates were assayed for their inhibitory effect against nitric oxide (NO) production in a lipopolysaccharide (LPS)-activated RAW264.7 macrophage cell line, among which andafocoumarins A and B exhibited a potent inhibition on LPS-activated NO production with IC50 values of 19.7 and 13.9μM, respectively, indicating their stronger inhibitory activity than l-N6-(1-iminoethyl)-lysine (IC50=23.7μM), a selective inhibitor of inducible nitric oxide synthase.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Sangkeun Son, Sung-Kyun Ko, Jong Won Kim, Jae Kyoung Lee, Mina Jang, In-Ja Ryoo, Gwi Ja Hwang, Min Cheol Kwon, Kee-Sun Shin, Yushi Futamura, Young-Soo Hong, Hyuncheol Oh, Bo Yeon Kim, Masashi Ueki, Shunji Takahashi, Hiroyuki Osada, Jae-Hyuk Jang, Jong Seog Ahn Twelve metabolites, including five highly oxygenated azaphilones, geumsanols A–E, along with seven known analogues were isolated from Penicillium sp. KCB11A109, a fungus derived from a ginseng field. Their structures were assigned by spectroscopic means (NMR and MS), and stereochemistries were determined by extensive spectroscopic analyses (1H–1H coupling constants, NOESY, and HETLOC) and chemical derivatizations (modified Mosher’s method and acetonide formation). The isolates were evaluated for their anticancer, antimicrobial, antimalarial activities, and phenotypic effects in zebrafish development. Of these compounds possessing no pyranoquinone core, only geumsanol E exhibited cytotoxic activities and toxic effects on zebrafish embryos, suggesting that a double bond at C-11 and C-12 is important for biological activity.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Henrique Bridi, Gari V. Ccana-Ccapatinta, Eveline D. Stolz, Gabriela C. Meirelles, Sérgio A.L. Bordignon, Stela M.K. Rates, Gilsane L. von Poser Three dimeric acylphloroglucinols, austrobrasilol A, austrobrasilol B and isoaustrobrasilol B were isolated from the flowers of Hypericum austrobrasiliense (Hypericaceae, section Trigynobrathys). Their structures were elucidated using mass spectrometry and NMR experiments (1D and 2D), and by comparison with previously reported data for other dimeric acylphloroglucinols isolated from Hypericum and Elaphoglossum genera. The three compounds were orally administered in mice at equimolar doses to uliginosin B (15mg/kg, p.o.) displaying antinociceptive activity in the hot-plate test. The compounds did not induce motor impairment in the rotarod apparatus.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Supichar Chokpaiboon, Siwattra Choodej, Nattawut Boonyuen, Thapong Teerawatananond, Khanitha Pudhom Five highly oxygenated chromones, rhytidchromones A–E, were isolated from the culture broth of a mangrove-derived endophytic fungus, Rhytidhysteron rufulum, isolated from Thai Bruguiera gymnorrhiza. Their structures were determined by analysis of 1D and 2D NMR spectroscopic data. The structure of rhytidchromone A was further confirmed by single-crystal X-ray diffraction analysis. These compounds were evaluated for cytotoxicity against four cancer cell lines (MCF-7, Hep-G2, Kato-3 and CaSki). All compounds, except for rhytidchromone D, displayed cytotoxicity against Kato-3 cell lines with IC50 values ranging from 16.0 to 23.3μM, while rhytidchromones A and C were active against MCF-7 cells with IC50 values of 19.3 and 17.7μM, respectively.
Publication date: March 2016 Source:Phytochemistry, Volume 123 Author(s): Marina Lifshits, Dimitri Kovalerchik, Shmuel Carmeli Five previously undescribed biopterin glycosides, microcystbiopterin A–E, were isolated from the extracts of two bloom materials of Microcystis spp. collected from a fishpond (IL-337) and Lake Kinneret (IL-347), Israel. The structure of the pterins was established by interpretation of their UV, CD, 1D and 2D NMR spectra and HR mass measurements. Microcystbiopterin D is the first heptose containing pterin glycoside to be reported in the literature. Their antimicrobial and cytotoxic properties were evaluated but all were found not active in both assays.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Yu-Ming Hsu, Tung-Ying Wu, Ying-Chi Du, Mohamed El-Shazly, Ludger Beerhues, Tran Dinh Thang, Hoang Van Luu, Tsong-Long Hwang, Fang-Rong Chang, Yang-Chang Wu The phytochemical investigation of the methanolic extract of Uvaria flexuosa (Annonaceae) leaves led to the isolation of seven compounds including, 3-methyl-4,5-dihydro-oxepine (flexuvaroxepine A), four polyoxygenated seco-cyclohexene (flexuvarin A–D) and two polyoxygenated cyclohexene (flexuvarol A–B) derivatives, together with four known flavones. The structures of the isolated compounds were elucidated using different spectroscopic techniques. A plausible biogenetic route of the new compounds was discussed. The anti-inflammatory activity of the isolated compounds was evaluated by superoxide anion generation and elastase release assays. Among the tested compounds, flexuvarol B and chrysin showed the most potent anti-inflammatory effect by inhibiting superoxide anion generation and elastase release from human neutrophils in response to fMLP with IC50 2.25–5.55μM. Moreover, 5-hydroxy-6,7-dimethoxy-flavone showed selective inhibitory activity on superoxide anion generation (IC50=1.19±0.34μM).
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Sidonie Tankeu, Ilze Vermaak, Weiyang Chen, Maxleene Sandasi, Alvaro Viljoen Stephania tetrandra (“hang fang ji”) and Aristolochia fangchi (“guang fang ji”) are two different plant species used in Traditional Chinese Medicine (TCM). Both are commonly referred to as “fang ji” and S. tetrandra is mistakenly substituted and adulterated with the nephrotoxic A. fangchi as they have several morphological similarities. A. fangchi contains aristolochic acid, a carcinogen that causes urothelial carcinoma as well as aristolochic acid nephropathy (AAN). In Belgium, 128 cases of AAN was reported while in China, a further 116 cases with end-stage renal disease were noted. Toxicity issues associated with species substitution and adulteration necessitate the development of reliable methods for the quality assessment of herbal medicines. Hyperspectral imaging in combination with partial least squares discriminant analysis (PLS-DA) is suggested as an effective method to distinguish between S. tetrandra and A. fangchi root powder. Hyperspectral images were obtained in the wavelength region of 920–2514nm. Reduction of the dimensionality of the data was done by selecting the discrimination information range (964–1774nm). A discrimination model with a coefficient of determination (R2) of 0.9 and a root mean square error of prediction (RMSEP) of 0.23 was created. The constructed model successfully identified A. fangchi and S. tetrandra samples inserted into the model as an external validation set. In addition, adulteration detection was investigated by preparing incremental adulteration mixtures of S. tetrandra with A. fangchi (10–90%). Hyperspectral imaging showed the ability to accurately predict adulteration as low as 10%. It is evident that hyperspectral imaging has tremendous potential in the development of visual quality control methods which may prevent cases of aristolochic acid nephropathy in the future.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Guillermo Marcial, Marina P. de Lampasona, Marta I. Vega, Emilio Lizarraga, Carmen I. Viturro, Alberto Slanis, Miguel A. Juárez, Miguel A. Elechosa, César A.N. Catalán The aerial parts of Lippia integrifolia (incayuyo) are widely used in northwestern and central Argentina for their medicinal and aromatic properties. The essential oil composition of thirty-one wild populations of L. integrifolia covering most of its natural range was analyzed by GC and GC–MS. A total of one hundred and fifty two terpenoids were identified in the essential oils. Sesquiterpenoids were the dominant components in all but one of the collections analyzed, the only exception being a sample collected in San Juan province where monoterpenoids amounted to 51%. Five clearly defined chemotypes were observed. One possessed an exquisite and delicate sweet aroma with trans-davanone as dominant component (usually above 80%). Another with an exotic floral odour was rich in oxygenated sesquiterpenoids based on the rare lippifoliane and africanane skeletons. The trans-davanone chemotype is the first report of an essential oil containing that sesquiterpene ketone as the main constituent. The absolute configuration of trans-davanone from L. integrifolia was established as 6S, 7S, 10S, the enantiomer of trans-davanone from ‘davana oil’ (Artemisia pallens). Wild plants belonging to trans-davanone and lippifolienone chemotypes were propagated and cultivated in the same parcel of land in Santa Maria, Catamarca. The essential oil compositions of the cultivated plants were essentially identical to the original plants in the wild, indicating that the essential oil composition is largely under genetic control. Specimens collected near the Bolivian border that initially were identified as L. boliviana Rusby yielded an essential oil practically identical to the trans-davanone chemotype of L. integrifolia supporting the recent view that L. integrifolia (Gris.) Hieron. and L. boliviana Rusby are synonymous.
The essential oil composition of 31 wild populations of Lippia integrifolia was analyzed. Using a hierarchical cluster analysis, five distinct chemotypes were detected, two of which are noteworthy by their unique chemical profiles: one characterized by high concentrations of trans-davanone and the other by containing rare sesquiterpenoids.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Athip Maha, Vatcharin Rukachaisirikul, Saowanit Saithong, Souwalak Phongpaichit, Wimarak Poonsuwan, Jariya Sakayaroj, Patchreenart Saparpakorn, Supa Hannongbua Investigation of the fungus Phoma herbarum PSU-H256 isolated from a leaf of Hevea brasiliensis resulted in the isolation of eight terezine derivatives (E–L) together with four known compounds. Their structures were established by analysis of spectroscopic evidence. For terezines E and H, their structures were confirmed by single-crystal X-ray diffraction crystallography. In addition, the absolute configuration at C-7 in terezine E was established by Mosher’s method. Terezines K and L were tested for antibacterial, antimalarial, antimycobacterial and cytotoxic activities, but were inactive.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Jie Gao, Qi-Bin Chen, Yong-Qiang Liu, Xue-Lei Xin, Ablimiti Yili, Haji Akber Aisa Ten diterpenoids, named macrorilone A–B, macroripremyrsinone A, macrorilathyrone A–B, macrorieuphorone A–B and macroricasbalone A–C, together with ten known diterpenoids, jatrophalone, sikkimenoids A–D, jatrophodione A, latilagascenes F, jolkinol B, 15β-O-benzoyl-5α-hydroxyisolathyrol and jatrophalactone were isolated from the whole plant of Euphorbia macrorrhiza C.A. Mey. These diterpenoids belong to six skeleton-types, including jatropholane, premyrsinane, lathyrane, euphoractin, casbene and rhamnofolane diterpenoids. Their structures were elucidated by extensive analysis of 1D, 2D NMR and HRESIMS spectroscopic data. The absolute configurations of macrorilone B, macroripremyrsinone A and macrorilathyrone A were established by comparing their experimental and calculated electronic circular dichroism (ECD) spectra. Several of the isolated compounds exhibited weak cytotoxicity against the KB and KBv200 cell lines with IC50 values ranging from 21.19 to 47.87μM. Some also showed multidrug resistance (MDR) reversal activity, among which macrorilathyrone B exhibited a remarkable inhibitory effect on P-gp-mediated drug exclusion.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Wen-Jing Wang, Lei Wang, Zhong Liu, Ren-Wang Jiang, Zhi-Wen Liu, Man-Mei Li, Qing-Wen Zhang, Yi Dai, Yao-Lan Li, Xiao-Qi Zhang, Wen-Cai Ye Eleven benzofuran dimers, (+)-dieupachinins A–E, (−)-dieupachinins A–E and dieupachinin F, a benzofuran trimer trieupachinin A, as well as seven known compounds were isolated from the roots of Eupatorium chinense. The enantiomers of racemates dieupachinins A–E were separated by chiral HPLC. The structures with absolute configurations were elucidated on the basis of spectroscopic data, X-ray diffraction analysis, and circular dichroism experiments. The isolated compounds were evaluated for their in vitro antiviral activities against respiratory syncytial virus (RSV).
Publication date: Available online 12 February 2016 Source:Phytochemistry Author(s): Anna-Katharina Aschenbrenner, Moonhyuk Kwon, Jürgen Conrad, Dae-Kyun Ro, Otmar Spring Sunflower is known to produce a variety of bisabolene-type sesquiterpenes and accumulates these substances in trichomes of leaves, stems and flowering parts. A bioinformatics approach was used to identify the enzyme responsible for the initial step in the biosynthesis of these compounds from its precursor farnesyl pyrophosphate. Based on sequence similarity with a known bisabolene synthases from Arabidopsis thaliana AtTPS12, candidate genes of Helianthus were searched in EST-database and used to design specific primers. PCR experiments identified two candidates in the RNA pool of linear glandular trichomes of sunflower. Their sequences contained the typical motifs of sesquiterpene synthases and their expression in yeast functionally characterized them as bisabolene synthases. Spectroscopic analysis identified the stereochemistry of the product of both enzymes as (Z)-γ-bisabolene. The origin of the two sunflower bisabolene synthase genes from the transcripts of linear trichomes indicates that they may be involved in the synthesis of sesquiterpenes produced in these trichomes. Comparison of the amino acid sequences of the sunflower bisabolene synthases showed high similarity with sesquiterpene synthases from other Asteracean species and indicated putative evolutionary origin from a β-farnesene synthase.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Nikolay A. Bushkov, Mark S. Veselov, Roman N. Chuprov-Netochin, Elena I. Marusich, Alexander G. Majouga, Polina B. Volynchuk, Daria V. Shumilina, Sergey V. Leonov, Yan A. Ivanenkov An enormous technological progress has resulted in an explosive growth in the amount of biological and chemical data that is typically multivariate and tangled in structure. Therefore, several computational approaches have mainly focused on dimensionality reduction and convenient representation of high-dimensional datasets to elucidate the relationships between the observed activity (or effect) and calculated parameters commonly expressed in terms of molecular descriptors. We have collected the experimental data available in patent and scientific publications as well as specific databases for various agrochemicals. The resulting dataset was then thoroughly analyzed using Kohonen-based self-organizing technique. The overall aim of the presented study is to investigate whether the developed in silico model can be applied to predict the agrochemical activity of small molecule compounds and, at the same time, to offer further insights into the distinctive features of different agrochemical categories. The preliminary external validation with several plant growth regulators demonstrated a relatively high prediction power (67%) of the constructed model. This study is, actually, the first example of a large-scale modeling in the field of agrochemistry.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Angela Bisio, Daniele Fraternale, Anna Maria Schito, Anita Parricchi, Fabrizio Dal Piaz, Donata Ricci, Mauro Giacomini, Barbara Ruffoni, Nunziatina De Tommasi Demethylfruticuline A and fruticuline A, the most abundant compounds from the surface extract of Salvia corrugata Vahl., have shown antibacterial, antitumor and cytotoxic activities. In order to obtain these icetexane diterpenes from in vitro cultures of S. corrugata, protocols were developed for callus production, micropropagation and shoot regeneration. Analysis of the regenerated shoots showed the presence of both icetexanes, micropropagated plants contained only fruticuline A, while the callus contained trace amounts of both diterpenes. The yield of fruticuline A was higher in the methanolic extract of regenerated shoots than in those of fresh leaves and fresh shoot tips. In addition to these diterpenes, the regenerated shoot and micropropagated plant extracts afforded seven other diterpenes, one icetexane and six abietanes, identified by UV, IR, 1D- and 2D-NMR and HR-MS analysis. Five compounds (19-acetoxy-7α-hydroxyroyleanone, 7β,20-epoxy-11,12,19-trihydroxyabieta-8,11,13-triene, 7,20-dihydrofruticuline A, 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone, 7β-ethoxy-6β,20:19,20-diepoxyroyleanone) were previously undescribed. Although the crude plant surface extract did not possess any antibacterial activity, methanolic extracts of in vitro tissues and two compounds, namely 7β-acetoxy-20-hydroxy-19,20-epoxyroyleanone and 7β-ethoxy-6β,20:19,20-diepoxyroyleanone, isolated in suitable amounts, were active in varying degrees against multidrug resistant clinical strains of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium, displaying MIC values ranging from 32, 64 to 128μg/mL.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Jia-Jian Wang, Hau Yin Chung, Yu-Bo Zhang, Guo-Qiang Li, Yao-Lan Li, Wei-Huan Huang, Guo-Cai Wang Six diterpenoids [crassifolin J, K, L, M, N and O] along with eleven known ones were isolated from the supercritical fluid extract (SFE) of the roots of Croton crassifolius (Euphorbiaceae). Their structures were elucidated using spectroscopic methods (IR, UV, HRESIMS, 1D and 2D NMR). The structure and stereochemistry of crassifolin J was confirmed by single-crystal X-ray diffraction analysis, and the absolute configurations of crassifolin K–M were determined by CD spectra. Twenty-three diterpenoids from this plant were screened for their anti-angiogenic activity using a wild-type zebrafish in vivo model. Four of the known compounds were active, of which penduliflaworosin possessed the best activity relative to the positive control (SU5416). Further study demonstrated that penduliflaworosin could inhibit vessel formation on Tg(fli1a:EGFP)y1-type zebrafish embryos.
Publication date: Available online 12 February 2016 Source:Phytochemistry Author(s): Serge Alain Tanemossu Fobofou, Chelsea Rebecca Harmon, Antoine Honoré Nkuete Lonfouo, Katrin Franke, Stephen M. Wright, Ludger A. Wessjohann In search for new or chemo-taxonomically relevant bioactive compounds from chemically unexplored Hypericum species, four previously undescribed natural products, named peplidiforones A–D were isolated and characterized from Hypericum peplidifolium A. Rich., together with six known compounds. The structures of all compounds were elucidated by extensive 1D- and 2D-NMR experiments, high resolution mass spectrometric analyses (HR-MS), and by comparison with data reported in the literature. Seven of these compounds are phenyl polyketides while three are acylphloroglucinol type compounds. Peplidiforone C, which possesses an unusual carbon skeleton consisting of a furan ring substituted by a 2,2-dimethylbut-3-enoyl moiety, is the first example of a prenylated furan derivative isolated from the genus Hypericum. The cytotoxicity, antifungal, and anti-herpes simplex virus type 1 (HSV-1) activities of extracts and compounds are described.
Publication date: February 2016 Source:Phytochemistry, Volume 122 Author(s): Hai Xuan Nguyen, Nhan Trung Nguyen, Phu Hoang Dang, Phuoc Thi Ho, Mai Thanh Thi Nguyen, Mao Van Can, Dya Fita Dibwe, Jun-ya Ueda, Suresh Awale Eight structurally diverse cassane diterpenes named tomocins A–H were isolated from the seed kernels of Vietnamese Caesalpinia sappan Linn. Their structures were determined by extensive NMR and CD spectroscopic analysis. Among the isolated compounds, tomocin A, phanginin A, F, and H exhibited mild preferential cytotoxicity against PANC-1 human pancreatic cancer cells under nutrition-deprived condition without causing toxicity in normal nutrient-rich conditions.
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