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Phytochemistry - published by Elsevier
Phytochemistry is the international journal of pure and applied plant chemistry, plant biochemistry and molecular biology.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Laurence Voutquenne-Nazabadioko , Reneta Gevrenova , Nicolas Borie , Dominique Harakat , Charlotte Sayagh , Alexander Weng , Mayank Thakur , Maya Zaharieva , Max Henry Eleven triterpenoid saponins were isolated from the roots of Gypsophila trichotoma Wender. (G. trichotoma Wender. var. trichotoma) (Caryophyllaceae), together with one known compound. The structures were established on the basis of extensive NMR analysis (1H, 13C NMR, COSY, TOCSY, ROESY, HSQC, and HMBC), completed by analysis of HR-ESI-MS and ESI-MSn. The saponins have the commonly found gypsogenin as the aglycone substituted at C-3 with trisaccharide and at C-28 with oligosaccharide through a fucose residue, as saponins isolated from Gypsophila perfoliata L. originated from China. The oligosaccharide attached to C-28 is substituted with acetyl and (or) sulfate groups.?he cytotoxicity of the saponin extract from G. trichotoma was evaluated against a rat alveolar macrophage-like cell line NR8383 and human leukemia cell lines U937 and BV-173. The synergistic effect of the aminoacyl saponins, previously isolated from G. trichotoma, was tested for its ability to enhance the cytotoxicity of the targeted toxin in HER14 cells.
Publication date: Available online 9 May 2013 Source:Phytochemistry Author(s): Magdalena Wujak , Mariusz Banach , Dorota Porowi?ska , Katarzyna Piskulak , Micha? Komoszy?ski Here we have isolated seven apyrase encoding cDNA sequences (StAPY4–StAPY10) from the potato variety Saturna tuber cDNA library by affecting necessary modifications in the screening protocol. The cDNA sequences were identified with a pair of primers complementary to the most conserved sequences identified in potato variety Desiree apyrase genes. Our data strongly suggest the multigenic nature of potato apyrase. All deduced amino acid sequences contain a putative signal sequence, one transmembrane region at the amino terminus and five apyrase conserved regions (ACRs) (except StAPY6). Phylogenetic analysis revealed that encoded proteins shared high level of DNA sequence identity among themselves, representing a family of proteins markedly distinct from other eukaryotic as well as prokaryotic apyrases. Two cDNA sequences (StAPY4 and StAPY6) were overexpressed in bacteria and recombinant proteins were found accumulated in inclusion bodies, even thought they were fused with thioredoxin-tag. Additionally, we present the first successful in vitro attempt at reactivation and purification of recombinant potato apyrase StAPY6. The ratio of ATPase/ADPase hydrolysis of recombinant StAPY6 was determined as 1.5:1. Unlike other apyrases the enzyme lacked ACR5 and was endowed with lower molecular weight, high specificity for purine nucleotides and very low specificity for pyrimidine, suggesting that StAPY6 is a potato apyrase, not described so far.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Toshihiro Akihisa , Xin Pan , Yasuhiro Nakamura , Takashi Kikuchi , Nami Takahashi , Masahiro Matsumoto , Eri Ogihara , Makoto Fukatsu , Kazuo Koike , Harukuni Tokuda Thirty-one limonoids and one tirucallane-type triterpenoid were isolated from the fruits of Melia azedarach (Meliaceae). The structures of 14 of these isolated compounds were elucidated on the basis of spectroscopic analyses and comparison with literature. All of these compounds were evaluated for their cytotoxic activities against HL60, A549, AZ521, and SK-BR-3 human cancer cell lines. Meliarachin C (IC50 0.65?M) and 3-O-deacetyl-4?-demethyl-28-oxosalannin (IC50 2.8?M) exhibited potent cytotoxic activity against HL60 cells, and this was demonstrated mainly due to the induction of apoptosis by flow cytometry. Western blot analysis suggested that both compounds induced apoptosis via both the mitochondrial and death receptor-mediated pathways. In addition, 25 compounds were evaluated for their inhibitory effects against the Epstein–Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells.
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Limonoids, meliarachin C and 3-O-deacetyl-4?-demethyl-28-oxosalannin, were isolated from fruits of Melia azedarach. They induced caspase-dependent apoptotic cell death in HL60 human leukemia cells.? Thirty-one limonoids and a triterpenoid were isolated from Melia azedarach fruits. ? Fourteen were previously unrecorded in the literature. ? Meliarachin C and a salannin derivative induced apoptotic cell death in HL60 cells. ? Meliarachin C and a salannin derivative exhibited selective toxicity in leukemia cells.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Wei Yuan , Ping Wang , Zushang Su , Victoria S. Wang , Shiyou Li Fifteen polyhydroxyoleanene saponins, aesculiosides C1–C15 (1–15), were isolated from husks of Aesculus californica. Their structures were established by extensive spectroscopic and chemical analyses. The triterpenoid saponins from A. californica have greater structural diversity than those from any other investigated species thus far in the genus Aesculus. The chemotaxonomic characteristic of aesculiosides C1–C15 is that the unit attached to the C-3 of the aglycone is a glucopyranosyl moiety, instead of a glucuronopyranosyl group in the saponins that have been isolated from other Aesculus species. The saponins isolated from A. californica then provide important evolutionary and chemotaxonomic knowledge of the Aesculus genus, a well-known intercontinental disjunct genus in the Northern hemisphere. Aesculiosides C1–C15 (1–15) showed cytotoxicity to human non-small cell lung tumor (A549) with GI50 ranged from 3.76 to >25?M.
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Fifteen polyhydroxyoleanene saponins were isolated from the husks of Aesculus californica. The saponins showed cytotoxicity to human non-small cell lung tumor (A549). Their structures provide important evidence for evolution and chemotaxonomy of Aesculus, a well-known intercontinental disjunct genus in the Northern hemisphere.? Fifteen saponins were isolated from the husks of Aesculus californica. ? These saponins have a glucopyranosyl moiety at C-3. ? These saponins provide evolutionary and taxonomic evidence for Aesculus. ? The saponins showed cytotoxicity against human non-small cell lung tumor (A549).
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): M. Jeevitha , T. Athiperumalsami , Venkataraman Kumar The amount of dietary fibre, mineral and vitamin were determined in root, rhizome and leaf of four commonly-available seagrasses, Cymodocea serrulata, Syringodium isoetifolium, Halophila ovalis and Halodule pinifolia at a station off Hare Island, Tuticorin (8°45? N, 78°12? E) in the Gulf of Mannar Biosphere region during premonsoon (July–September), monsoon (October–December) and postmonsoon (January–March) seasons of 2010–2011 and 2011–2012 study period. The entire tissues from each seagrass were subjected to HPLC and GC analysis for determining amino acid and fatty acid profiles respectively. The rhizomes of H. ovalis possessed highest amount of dietary fibre during monsoon. C. serrulata showed maximum content of K in rhizome during monsoon. Highest amount of Ca and Mg was recorded in the rhizome and leaf of H. pinifolia in postmonsoon. S. isoetifolium exhibited peak value for Na in its rhizome during monsoon. Highest amounts of Vitamin A, C and E were registered in the rhizome/root of Cymodocea during postmonsoon. Vitamin B3 was maximum in the root of Syringodium in monsoon. Eighteen of the twenty amino acids detected in seagrasses were found to the maximum level in Halodule. Syriingodium showed the highest amount of six of the seven fatty acids recorded.
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Vitamin A content recorded in different parts of Cymodocea serrulata in different seasons. Maximum amount of Vitamin A was registered in the rhizome of Cymodocea during the postmonsoon of 2010–11 and 2011–12, respectively.? First report on certain seagrass phytochemical. ? Dietary fiber highest in rhizome of Halophila. ? Highest K (Cymodocea), Ca & Mg (Halodule) and Na (Syringodium). ? Max vit A (rhizome), C & E (root) of Cymodocea and B3 (Syringodium, root). ? Max amount of amino acids in Halodule and of fatty acids in Syringodium.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Fong-Chin Huang , Wilfried Schwab Plant epoxide hydrolases (EH) form two major clades, named EH1 and EH2. To gain a better understanding of the biochemical roles of the two classes, NbEH1.1 and NbEH2.1 were isolated from Nicotiana benthamiana and StEH from potato and heterologously expressed in Escherichia coli. The purified recombinant proteins were assayed with a variety of substrates. NbEH1.1 only accepted some aromatic epoxides, and displayed the highest enzyme activity towards phenyl glycidyl ether. In contrast, NbEH2.1 displayed a broad substrate range and similar substrate specificity as StEH. The latter enzymes showed activity towards all fatty acid epoxides examined. The activity (Vmax) of NbEH1.1 towards phenyl glycidyl ether was 10 times higher than that of NbEH2.1. On the contrary, NbEH2.1 converted cis-9,10-epoxystearic acid with Vmax of 3.83?molminmg?1 but NbEH1.1 could not hydrolyze cis-9,10-epoxystearic acid. Expression analysis revealed that NbEH1.1 is induced by infection with tobacco mosaic virus (TMV) and wounding, whereas NbEH2.1 is present at a relatively constant level, not influenced by treatment with TMV and wounding. NbEH1.1 transcripts were present predominantly in roots, whereas NbEH2.1 mRNAs were detected primarily in leaves and stems. Overall, these two types of tobacco EH enzymes are distinguished not only by their gene expression, but also by different substrate specificities. EH1 seems not to participate in cutin biosynthesis and it may play a role in generating signals for activation of certain defence and stress responses in tobacco. However, members of the EH2 group hydrate fatty acid epoxides and may be involved in cutin monomer production in plants.
Publication date: Available online 14 May 2013 Source:Phytochemistry Author(s): Evangelos C. Tatsis , Hartmut Böhm , Bernd Schneider The intense color of yellow Papaver nudicaule flowers is conferred by the presence of nudicaulins, a group of alkaloids with a unique pentacyclic skeleton composed of an indole ring and a polyphenolic moiety. Petals from eight different Papaveraceae species composed of different color varieties were probed for the presence of nudicaulins. In addition to their occurrence in yellow P. nudicaule flowers, nudicaulins I–VIII were detected and quantified in orange flowers of P. nudicaule, and in yellow and orange Papaver alpinum flowers. Meconopsis cambrica petals showed a divergent nudicaulin spectrum, with compounds having an attached 3-hydroxy-3-methyl-glutaryl group (HMG) instead of a malonyl unit at one of the glucose units. Flavonols and anthocyanins that accompany nudicaulins were identified. The taxonomical significance of the occurrence of nudicaulins is briefly discussed.
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Nudicaulins, a unique group of indole alkaloids, are responsible for the petal color of three yellow-blooming papaveraceous species, Papaver nudicaule, Papaver alpinum and Meconopsis cambrica. The petal color of orange cultivars of P. nudicaule and P. alpinum is conferred by the co-occurrence of nudicaulins with pelargonidin derivatives and the petal color of a red P. nudicaule cultivar is due to pelargonidins alone. Two acylated nudicaulins have been found in M. cambrica.
Publication date: Available online 8 May 2013 Source:Phytochemistry Author(s): Yngvar Gauslaa , Massimo Bidussi , Knut Asbjørn Solhaug , Johan Asplund , Per Larsson Acetone-extractable carbon based secondary compounds (CBSCs) were quantified in two epiphytic lichens to study possible effects of external factors (season and aspect) on secondary chemistry and to relate defense investments to biomass growth and changes in specific thallus mass (STM). At the end of four separate annual cycles starting in each of the four seasons, the cyanolichen Lobaria scrobiculata and the cephalolichen Lobaria pulmonaria (green algae as the primary photobiont and with localized Nostoc in internal cephalodia) were monitored in their natural forest habitats and after being transplanted at three contrasting aspects in open sites. Season strongly influenced most CBSCs. Medullary CBSCs in both species were twice as high in summer as in winter. Aspect hardly affected major CBSCs, whereas transplantation from forest to clear-cut slightly reduced these compounds. No major CBSCs in any species showed a trade-off with growth rate. Dry matter- as well as thallus area-based medullary CBSC contents increased with STM. The cortical usnic acid strongly increased with growth rate and followed spatial, but not seasonal variations in light exposure. Maximal CBSC levels during seasons with most herbivores is consistent with the hypothesis inferring that herbivory is a major selective force for CBSCs. Lack of trade-off between growth and defence investments suggests that these two processes do not compete for photosynthates.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Hala M. Hammoda , Nabila M. Ghazy , Fathalla M. Harraz , Mohamed M. Radwan , Mahmoud A. ElSohly , Ingy I. Abdallah Two oligosaccharides (1,2) and a stereoisomer of di-p-coumaroylquinic acid (3) were isolated from the aerial parts of Tribulus terrestris along with five known compounds (4–8). The structures of the compounds were established as O-?-d-fructofuranosyl-(2?6)-?-d-glucopyranosyl-(1?6)-?-d-fructofuranosyl-(2?6)-?-d-fructofuranosyl-(2?1)-?-d-glucopyranosyl-(6?2)-?-d-fructofuranoside (1), O-?-d-glucopyranosyl-(1?4)-?-d-glucopyranosyl-(1?4)-?-d-glucopyranosyl-(1?2)-?-d-fructofuranoside (2), 4,5-di-p-cis-coumaroylquinic acid (3) by different spectroscopic methods including 1D NMR (1H, 13C and DEPT) and 2D NMR (COSY, TOCSY, HMQC and HMBC) experiments as well as ESI-MS analysis. This is the first report for the complete NMR spectral data of the known 4,5-di-p-trans-coumaroylquinic acid (4).The antioxidant activity represented as DPPH free radical scavenging activity was investigated revealing that the di-p-coumaroylquinic acid derivatives possess potent antioxidant activity so considered the major constituents contributing to the antioxidant effect of the plant.
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Phytochemical investigation of Tribulus terrestris L. led to the isolation of chemical constituents. Moreover, the antioxidant activity of the plant and isolated compounds was investigated.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Paolo Zucca , Enrico Sanjust , Martina Loi , Francesca Sollai , Mauro Ballero , Manuela Pintus , Antonio Rescigno Ferula communis (L.), a plant belonging to Apiaceae, is widely present in Sardinia, Italy. Currently, interest in F. communis focuses on the presence of two chemotypes in the wild. One chemotype is poisonous to animals, whereas the other chemotype is non-poisonous. Polyphenol oxidase (PPO) has been extracted and partially purified from the two chemotypes of F. communis. The biochemical characterization of the enzymes showed significant differences. In particular, while the two PPOs were not able to use 6- and 7-hydroxycoumarin as substrates, they showed distinct specificity for 6,7- and 7,8-dihydroxycoumarin. Significant differences in the enzyme behavior towards common PPO inhibitors were also observed. In addition, activation energy and activation energy for denaturation were determined, showing significant differences between FP-PPO and FNP-PPO, particularly for denaturation kinetics. The possible roles of the two PPOs in determining differences in composition and toxicity of the two F. communis chemotypes are also discussed.
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Polyphenol oxidase has been extracted from poisonous and non-poisonous chemotypes of Ferula communis. The possible role of PPO in toxicity of poisonous chemotype is discussed.? Ferula communis is a plant belonging to Apiaceae, widely present also in Sardinia. ? Two chemotypes, poisonous and non-poisonous of F. communis are present in the wild. ? Polyphenol oxidase was extracted, purified and characterized from both chemotypes. ? PPO from both chemotypes showed different behavior towards substrates and inhibitors.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): M. Barbi? , E.A. Willer , M. Rothenhöfer , J. Heilmann , R. Fürst , G. Jürgenliemk Rusci rhizoma extracts are traditionally used against chronic venous disorders (CVD). To determine the effect of its secondary plant metabolites on the endothelium, phenolic compounds and saponins from Butcher’s broom were isolated from a methanolic extract, and their activity on the thrombin-induced hyperpermeability of human microvascular endothelial cells (HMEC-1) was investigated in vitro.In addition to the six known spirostanol saponins deglucoruscin (5), 22-O-methyl-deglucoruscoside (6), deglucoruscoside (7), ruscin (8), ruscogenin-1-O-(?-l-rhamnopyranosyl-(1?2)-?-d-galactopyranoside (9) and 1-O-sulpho-ruscogenin (10), three new spirostanol derivatives were isolated and identified: 3?-O-acetyl-4?-O-sulphodeglucoruscin (1), 4?-O-(2-hydroxy-3-methylpentanoyl)-deglucoruscin (2) and 4?-O-acetyl-deglucoruscin (3). Furthermore, the coumarin esculin (4), which is also prominently present in other medicinal plants used in the treatment of CVD, was isolated for the first time from Rusci rhizoma. Five of the isolated steroid derivatives (2, 5, 8, 9 and 10) and esculin (4) were tested for their ability to reduce the thrombin-induced hyperpermeability of endothelial cells in vitro, and the results were compared to those of the aglycone neoruscogenin (11). The latter compound showed a slight but concentration-dependent reduction in hyperpermeability to 71.8% at 100?M. The highest activities were observed for the spirostanol saponins 5 and 8 and for esculin (4) at 10?M, and these compounds resulted in a reduction of the thrombin-induced hyperpermeability to 41.9%, 42.6% and 53.3%, respectively. For 2, 5 and 8, the highest concentration tested (100?M) resulted in a drastic increase of the thrombin effect. The effect of esculin observed at a concentration of 10?M was diminished at 100?M. These in vitro data provide insight into the pharmacological mechanism by which the genuine spirostanol saponins and esculin can contribute to the efficacy of Butcher’s broom against chronic venous disorders.
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Three new spirostanol saponins, six known and the coumarin esculin were isolated from Rusci rhizoma. Esculin, five isolated saponins and the aglycone neoruscogenin were tested for their ability to reduce the thrombin induced hyperpermeability of endothelial cells in vitro. Deglucoruscin, 1-O-sulpho-ruscogenin, ruscin and esculin significantly reduce the hyperpermeability at 10?M.? We isolated six known and three new saponins from Rusci rhizoma.. ? Esculin is the first coumarin isolated from Butcher’s broom. ? Endothelial hyperpermeability was reduced by most isolated substances in vitro.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Marco Clericuzio , Roberto Negri , Maurizio Cossi , Gianluca Gilardoni , Davide Gozzini , Giovanni Vidari Two rare cadinane-type sesquiterpenes, lyophyllone A (1) and lyophyllanetriol A (2), were isolated from the mushroom Lyophyllum transforme. The structures were elucidated on the basis of exhaustive NMR techniques, together with MS, UV–Vis and molecular modelling. The absolute configuration of lyophyllone A was determined by ab initio theoretical CD calculation performed by Density Functional Theory (DFT) using the B3PW91/6-31G(d,p) basis set. The experimental CD were found to be in good agreement with the corresponding population-weighted theoretical CD spectra, allowing for the determination of the absolute stereochemistry of the compound.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Christina L. Nord , Audrius Menkis , Rimvydas Vasaitis , Anders Broberg The secondary metabolites of the saprotrophic wood-decay basidiomycete fungus Granulobasidium vellereum were studied. Six sesquiterpenes were obtained; 2-hydroxycoprinolone (1), 8-deoxy-4a-hydroxytsugicoline (2), 8-deoxydihydrotsugicoline (3), which were previously not described, radulone A and B, and coprinolone ketodiol. Additionally, base-treatment of 1 yielded the diagnostic degradation products 1a and 1b, whereas radulone A was found to form 4 under mild acidic conditions. The structures were determined by NMR, MS, CD and polarimetry, along with biosynthetic considerations. Radulone A fully inhibited the spore germination of the potentially competing fungi Phlebiopsis gigantea, Coniophora puteana and Heterobasidion occidentale at 10?M, 500?M and 100?M, respectively. None of the other substances tested gave rise to any growth inhibition.
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The protoilludane sesquiterpenes 2-hydroxycoprinolone, 8-deoxy-4a-hydroxytsugicoline, 8-deoxydihydrotsugicoline, which were previously not described, radulone A and B, and coprinolone ketodiol were obtained from the wood-decay fungus Granulobasidium vellereum. The structures were elucidated with spectroscopic techniques and tested for biological activity against a selection of potential natural antagonists to G. vellereum.? The secondary metabolites of the fungus Granulobasidium vellereum were studied. ? Six protoilludanes were isolated, of which three were not previously described. ? The compounds were tested against potential natural antagonists to G. vellereum.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Ariel Salvatierra , Paula Pimentel , María Alejandra Moya-León , Raúl Herrera Anthocyanins and proanthocyanidins (PAs), flavonoid-derived metabolites with different physiological roles, are produced by plants in a coordinated manner during fruit development by the action of transcription factors (TFs). These regulatory proteins have either an activating or repressing effect over structural genes from the biosynthetic pathway under their control. FaMYB1, a TF belonging to the R2R3-MYB family and isolated from commercial strawberry fruit (Fragaria×ananassa), was reported as a transcriptional repressor and its heterologous over-expression in tobacco flowers suppressed flavonoid-derived compound accumulation. FcMYB1, an ortholog of FaMYB1 isolated from the white Chilean strawberry (Fragaria chiloensis ssp. chiloensis f. chiloensis), showed higher transcript levels in white (F. chiloensis) than in red (F.×ananassa cv. Camarosa) fruits. In order to assess its contribution to the discolored phenotype in F. chiloensis, FcMYB1 was transiently down-regulated in planta using an RNAi-based approach. Quantitative real-time PCR on FcMYB1 down-regulated fruits resulted an up-regulation of anthocyanidin synthase (ANS) and a strong repression of anthocyanidin reductase (ANR) and leucoanthocyanidin reductase (LAR) transcript accumulation. In addition, these fruits showed increased concentrations of anthocyanins and undetectable levels of flavan 3-ols. Altogether, these results indicate a role for FcMYB1 in regulation of the branching-point of the anthocyanin/PA biosynthesis determining the discolored phenotype of the white Chilean strawberry fruit.
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Transient transformation of strawberry fruit was analyzed focusing on accumulation of anthocyanins. Lower FcMYB1 transcript level was related with a more pigmented phenotype and changes in both transcriptional profiles of structural genes of flavonoid pathway and flavonoid compounds.? FcMYB1, ortholog of FaMYB1 (a suppressor of flavonoid biosynthesis) was cloned from white strawberry Fragaria chiloensis. ? Expression of FcMYB1 was higher in white strawberry than in red strawberry during fruit development. ? RNAi silencing construct depleted FcMYB1 mRNA levels in white strawberry fruits, enhancing their pigmentation. ? Fruits with lower transcript levels of this TF showed increased contents of anthocyanin and decreased levels of flavan 3-ols.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Rui Feng , Ting Wang , Wei Wei , Ren Xiang Tan , Hui Ming Ge A phytochemical study of Cryptocarya maclurei led to isolation of five flavanones, cryptogiones G–H, and a polyketide, cryptomaclurone. The structures of the isolates were elucidated by analysis of the 1D and 2D NMR spectroscopic data, and their absolute configurations were determined by CD methods. A putative biosynthetic pathway to them is proposed. Cytotoxicity of these compounds evaluated against KB, SGC-7901 and SW 1116 cancer cell lines, with only cryptomaclurone exhibiting moderate cytotoxicity (IC50 28.2, 28.4 and 16.4?M, respectively).
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Flavonoids, cryptogiones G–K, and a polyketide, cryptomaclurone, were isolated from the stems of Cryptocarya maclurei. A putative biosynthetic pathway to these compounds was proposed. Cryptomaclurone exhibited moderate cytotoxicity.? Phytochemical constituents of Cryptocarya maclurei were investigated. ? Five flavonoids and a polyketide were isolated. ? A putative biosynthetic pathway to the isolates was proposed. ? The polyketide exhibited moderate cytotoxicity.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Stijn Ceunen , Jan M.C. Geuns As part of an ongoing study on the effects of photoperiodism on the metabolism of steviol glycosides (SVglys) in Stevia rebaudiana, the spatio-temporal variations of free steviol (SV) have now been evaluated. For its quantitation, an internal standard method was used, based upon a specific fluorometric detection of SV as its methoxycoumarinyl derivative. The level of free SV in leaves did not exceed 30?g/g dry wt and was at least 1000-fold smaller than that of its glycosidic conjugates. In other organs, free SV was mainly measured in stem tissue and apices, with relatively large amounts measured in the latter. Similarly to SVglys, the content of free SV was influenced by photoperiod and genotype. In plants grown under long-days (LD) of 16h, more spatial variations were seen compared to those under short-days (SD) of 8h. In the former, upper leaves contained almost four times more free SV compared to lower ones near the end of vegetative growth. In addition, the correlation between SV and its glycosidic conjugates was more linear under SD. Despite the variability of SV levels, a decrease was noted in all conditions after flower opening, which can be related a decreased transcription of the biosynthetic genes involved.
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In Stevia rebaudiana, the spatio-temporal variations in steviol content were strongly influenced by photoperiod and genotype, yet in most conditions, a significant decline was seen after flower opening.? Steviol is the aglycone of the sweet steviol glycosides in Stevia rebaudiana. ? Free steviol level in leaves is at least 1000-fold smaller than that of its glycosides. ? Steviol content is strongly influenced by photoperiod and genotype. ? A general decrease was seen after flower opening. ? Under short-days, a linear correlation exists between steviol and its glycosides.
Publication date: Available online 18 May 2013 Source:Phytochemistry Author(s): Seikou Nakamura , Katsuyoshi Fujimoto , Takahiro Matsumoto , Souichi Nakashima , Tomoe Ohta , Keiko Ogawa , Hisashi Matsuda , Masayuki Yoshikawa The methanolic extract from the flower buds of Prunus mume, cultivated in Zhejiang Province, China, showed an inhibitory effect on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. From the methanolic extract, five acylated sucroses, mumeoses A–E, and three acylated quinic acid analogs, 5-O-(E)-p-coumaroylquinic acid ethyl ester, and mumeic acid-A and its methyl ester, were isolated together with 13 known compounds. The chemical structures of the compounds were elucidated on the basis of chemical and physicochemical evidence. Inhibitory effects of the isolated compounds on melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells were also investigated. Acylated quinic acid analogs substantially inhibited melanogenesis. In particular, 5-O-(E)-feruloylquinic acid methyl ester exhibited a potent inhibitory effect [inhibition (%): 21.5±1.0 (P<0.01) at 0.1?M]. Moreover, its biological effect was much stronger than that of the reference compound, arbutin [inhibition (%): 10.6±0.6 (P<0.01) at 10?M]. Interestingly, the obtained acylated quinic acid analogs displaying melanogenesis inhibitory activity showed no cytotoxicity [cell viability >97% at 10?M]. It is concluded that acylated quinic acid analogs are promising therapeutic agents for the treatment of skin disorders.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Naomi Oyama-Okubo , Tomoyuki Sakai , Toshio Ando , Masayoshi Nakayama , Tomoyoshi Soga Emission of floral scent benzenoid/phenylpropanoid compounds in Petunia axillaris increases significantly at night, a change that is primarily determined by the endogenous concentration of these compounds in the corolla. Among wild type P. axillaris plants, there are lines that emit different amounts of scent. To understand how the nocturnal rhythm of floral scent concentrations is controlled, the concentration profiles of metabolites in the scent biosynthetic pathway in two lines of P. axillaris, a strongly scented line and a weakly scented line, are reported. In the strongly scented line, the concentration of a series of compounds from glucose-6-phosphate (G6P) to the scent compounds changed synchronously. In the weakly scented lines, the concentrations of some metabolites including 6-phosphogluconate (6PG) and downstream metabolites of shikimic acid were remarkably lower, suggesting a reduction in metabolism of G6P to 6PG and the metabolism of shikimic acid in the weakly scented line. Nocturnal increases in the concentrations of sucrose, fructose, and glucose were not found in strongly scented line. Nocturnal increases in concentrations of S-adenosylhomocysteine (SAH) and methionine and reductions in the concentrations of S-adenosylmethionine (SAM), a methylation donor to benzenoid-skeletons, were observed only in strongly scented line. It is concluded that the biosynthetic regulation of each step from G6P to the volatile scent benzenoids is performed by, at least in part, concentrations of substrates, and the regulation also affects concentrations of SAM cycle compounds.
Publication date: Available online 14 May 2013 Source:Phytochemistry Author(s): H. Baharum , W.-C. Chu , S.-S. Teo , K.-Y. Ng , R. Abdul Rahim , C.-L. Ho Vanadium-dependent haloperoxidases belong to a class of vanadium enzymes that may have potential industrial and pharmaceutical applications due to their high stability. In this study, the 5?-flanking genomic sequence and complete reading frame encoding vanadium-dependent bromoperoxidase (GcVBPO1) was cloned from the red seaweed, Gracilaria changii; and the recombinant protein was biochemically characterized. The deduced amino acid sequence of GcVBPO1 is 1818 nucleotides in length, sharing 49% identity with the vanadium-dependent bromoperoxidases from Corralina officinalis and Cor. pilulifera, respectively. The amino acid residues associated with the binding site of vanadate cofactor were found to be conserved. The Km value of recombinant GcVBPO1 for Br? was 4.69mM, while its Vmax was 10.61?katmg?1 at pH 7. Substitution of Arg379 with His379 in the recombinant protein caused a lower affinity for Br?, while substitution of Arg379 with Phe379 not only increased its affinity for Br? but also enabled the mutant enzyme to oxidize Cl?. The mutant Arg379Phe was also found to have a lower affinity for I?, as compared to the wild-type GcVBPO1 and mutant Arg379His. In addition, the Arg379Phe mutant has a slightly higher affinity for H2O2 compared to the wild-type GcVBPO1. Multiple cis-acting regulatory elements associated with light response, hormone signaling, and meristem expression were detected at the 5?-flanking genomic sequence of GcVBPO1. The transcript abundance of GcVBPO1 was relatively higher in seaweed samples treated with 50 parts per thousand (ppt) artificial seawater (ASW) compared to those treated in 10 and 30ppt ASW, in support of its role in the abiotic stress response of seaweed.
Publication date: Available online 9 May 2013 Source:Phytochemistry Author(s): Ifat Parveen , Thomas Wilson , Iain S. Donnison , Alan R. Cookson , Barbara Hauck , Michael D. Threadgill Society demands chemicals from sustainable sources. Identification of commercially important chemicals in crops increases value in biorefineries and reduces reliance on petrochemicals. Miscanthus sinensis and Miscanthus sacchariflorus are high-yielding distinct plants, which are sources of high-value chemicals and bioethanol through fermentation. Cinnamates in leaves, stems and flowers were analysed by LC-ESI-MSn. Free phenols were extracted and separated chromatographically. More than twenty hydroxycinnamates were identified by UV and LC-ESI-MSn. Several cinnamate hexosides were detected in the M. sinensis flower and in M. sacchariflorus (leaf and stem). Hydroxybenzoic acids and their hexosides were observed in leaf and stem of M. sacchariflorus. Higher concentrations of 3-feruloylquinic acid were observed in M. sacchariflorus stem, suggesting a role in cell-wall biosynthesis. This technique can be used to screen plants in a mapping family to identify genotypes/species with high concentrations of phenols. Plants with low concentrations of antimicrobial phenols may be good feedstocks for fermentation.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Freddy Guihéneuf , Lionel Ulmann , Virginie Mimouni , Gérard Tremblin The marine flagellate Pavlova lutheri is a microalga known to be rich in long-chain polyunsaturated fatty acids (LC-PUFAs) and able to produce large amounts of n-3 fatty acids, such as eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). As no previous study had attempted to measure the metabolic step of fatty acid synthesis in this alga, we used radiolabeled precursors to explore the various desaturation and elongation steps involved in LC-PUFA biosynthesis pathways. The incorporation of 14C-labeled palmitic ([1-14C] 16:0) and dihomo-?-linolenic ([1-14C] 20:3n-6) acids as ammonium salts within the cells was monitored during incubation periods lasting 3, 10 or 24h. Total lipids and each of the fatty acids were also monitored during these incubation periods. A decrease in the availability and/or accessibility of the radiolabeled substrates was observed over the incubation time. This decrease with incubation time observed using [1-14C] 16:0 and [1-14C] 20:3n-6 as substrates was used to monitor the conversion of 14C-labeled arachidonic acid ([1-14C] 20:4n-6) into longer and more unsaturated fatty acids, such as 20:5n-3 and 22:6n-3, over shorter incubation times (1 and 3h). A metabolic relationship between the n-6 and n-3 fatty acid series was demonstrated in P. lutheri by measuring the ?17-desaturation activity involved in the conversion of eicosatetraenoic acid to 20:5n-3. Our findings suggest that the biosynthesis pathway leading to n-3 LC-PUFA involves fatty acids of the n-6 family, which act as precursors in the biosynthesis of 20:5n-3 and 22:6n-3. This preliminary work provides a method for studying microalgal LC-PUFA biosynthesis pathways and desaturase and elongase activities in vivo using externally-radiolabeled fatty acid precursors as substrates. The use of the [1-14C] 20:4n-6 substrate also highlighted the relationships between the n-6 and the n-3 fatty acid series (e.g. ?17-desaturation), and the final elongation and desaturation steps required for n-3 LC-PUFA formation in P. lutheri.
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The ?17-desaturation involved in the conversion of eicosatetraenoic to eicosapentaenoic acids suggests that the main biosynthetic pathway leading to n-3 LC-PUFAs in Pavlova lutheri involves n-6 fatty acid precursors. The results also reflect the activity of the final desaturation and elongation steps required for n-3 LC-PUFA formation.? Use of 14C-radiolabeled substrates to study microalgal LC-PUFA pathways in vivo. ? ?17-Desaturation activity involved in n-3 LC-PUFA synthesis. ? Biosynthesis pathway leading to n-3 LC-PUFA involves fatty acids of the n-6 family.
Publication date: Available online 7 May 2013 Source:Phytochemistry Author(s): Nadezda V. Khodorova , Alexey L. Shavarda , Michelle Lequart-Pillon , Jean-Claude Laberche , Olga V. Voitsekhovskaja , Michèle Boitel-Conti Numerous species of the genus Corydalis (Papaveraceae) produce a large spectrum of benzylisoquinoline alkaloids (BIA), some of which are of potential therapeutic value, but no information on sites of their biosynthesis and compartmentation is available. This study focuses on the biosynthesis, compartmentation and seasonal dynamics of BIA in Corydalis bracteata (Steph. ex Willd) Pers., a geophyte with a very short spring vegetation period, which for the rest of the year is represented by underground tubers with buds. It was found that all organs of C. bracteata contained high levels of BIA, the highest concentrations being detected in underground tuber buds in early autumn. Neither xylem nor phloem sap contained alkaloids throughout the year but BIA were present in the apoplastic wash fluid of the tuber. The absence of long-distance transport of alkaloids was confirmed by the experiment using an isotopically labeled tracer, [ring-13C6]-tyramine: when whole plants were fed with the tracer with via the roots, the alkaloids became labeled in the roots only and not in other organs. However, when detached roots, leaves, tubers and stems were exposed to [ring-13C6]-tyramine, the label was incorporated into alkaloids in all organs. We conclude that no long-distance translocation of alkaloids occurs between organs of C. bracteata, while in the tuber the cell-to-cell transport of alkaloids could occur via the apoplast. In contrast to other BIA-producing species, every organ of C. bracteata was found to be capable of de novo biosynthesis of the full complement of alkaloids.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Louise V. Michaelson , Jonathan E. Markham , Simone Zäeuner , Midori Matsumoto , Ming Chen , Edgar B. Cahoon , Johnathan A. Napier Triunsaturated sphingolipid long chain bases (LCBs) have previously been reported in some specialised tissues of marine invertebrates. We report the presence of similar LCBs in the marine diatom Thalassiosira pseudonana and identify the cytochrome b5-fusion desaturase responsible for the introduction of the third double bond at the ?10 position in d18:3?4,8,10. This study extends the catalytic repertoire of the cytochrome b5 fusion desaturase family, also indicating the presence of orthologues in other marine invertebrates. The function of these polyunsaturated sphingolipid LCBs is currently unknown but it was previously suggested that they play an essential role in primitive animals. The identification of the desaturase responsible for their synthesis paves the way for further studies.
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A diverged member of the cytochrome b5-fusion desaturase family has been functionally characterised as an unusual sphingolipid desaturase, responsible for the synthesis of trienes.? Functional characterisation of a new sphingolipid modifying enzyme in yeast. ? Identification of the enzyme responsible for generating triunsaturated LCBs. ? Addition of a new activity to the cytochrome b5 fusion desaturase family. ? Detection of orthologues in highly divergent animal species.
Publication date: Available online 3 May 2013 Source:Phytochemistry Author(s): Gloria Castellano , Juan Luis González-Santander , Ana Lara , Francisco Torrens A total of 74 flavonoid compounds are classified into a periodic table by using an algorithm based on the entropy of information theory. Seven features in hierarchical order are used to classify structurally the flavonoids. From these features, the first three mark the group or column, while the last four are used to indicate the row or period in a table of periodic classification. Those flavonoids in the same group and period are suggested to show maximum similarity in properties. Furthermore, those with only the same group will present moderate similarity. In this report, the flavonoid compounds in the table, whose experimental data in bioactivity and antioxidant properties have been previously published, are related.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): E. González-Burgos , M.E. Carretero , M.P. Gómez-Serranillos Kaurane diterpenes have been shown to possess antioxidant properties. As a part of our ongoing studies on the identification of biologically active diterpenes from Sideritis spp., we have previously isolated and structurally elucidated the major kaurane diterpenes foliol, linearol and sidol, in a previous study from the aerial parts of Sideritis linearifolia and Sideritis leucantha. We have now examined the ability of these compounds to protect PC12 cells in an H2O2-induced oxidative stress model. Linearol and sidol (5 and 10?M, 24h) significantly attenuated loss of mitochondrial function (MTT assay) and membrane integrity (LDH assay) and morphological changes associated with H2O2-mediated cytotoxicity. Moreover, pretreatments with linearol and sidol effectively reduced intracellular ROS production, decreased MDA levels (lipid peroxidation product) and restored GSH/GSSG ratio. Furthermore, analysis of the effect of diterpenes on antioxidant enzymes showed that linearol and sidol induced the upregulation and protein expression of the main antioxidant enzymes CAT, SOD, GPx, GR and HO-1. Considering molecular mechanisms for maintaining cellular redox homeostasis by linearol and sidol, it would appear that the Nrf2 transcription factor seems to be involved. These results indicate that linearol and sidol are potential cytoprotective compounds, through antioxidant mechanisms, under H2O2-induced oxidative stress.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Roman Lang , Tobias Fromme , Anja Beusch , Anika Wahl , Martin Klingenspor , Thomas Hofmann Atractyloside (1) and carboxyatractyloside (2) are well-known inhibitors of the adenine nucleotide translocase (ANT) in mitochondria, thus effectively blocking oxidative phosphorylation. Structurally related derivatives atractyligenin (3), 2-O-?-d-glucopyranosyl-atractyligenin (4), 3?-O-?-d-glucopyranosyl-2?-O-isovaleryl-2?-(2-desoxy-atractyligenin)-?-d-glucopyranoside (5), and 2-O-?-d-glucopyranosyl-carboxyatractyligenin (6) were isolated from raw beans of Coffea L. and the impact of 1–6 on ANT activity was evaluated in isolated mitochondria. Among the coffee components, 6 significantly inhibited ANT activity leading to reduced respiration. Quantitative analysis in commercial coffees, experimental roastings of coffee, and model experiments using purified compound 6 consistently revealed a complete degradation during thermal treatment. In comparison, raw coffee extracts were found to contain high levels of 6, which are therefore expected to be present in food products enriched with raw coffee extracts. This implies the necessity of analytically controlling the levels of 6 in raw coffee extracts when used as additives for food products.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): M. Iqbal Choudhary , Mohammad Yasin Mohammad , Syed Ghulam Musharraf , Ismail Onajobi , Akhtar Mohammad , Itrat Anis , Muhammad Raza Shah , Atta-ur-Rahman Microbial transformation of clerodane lactone (1) by a plant pathogen fungus, Rhizopus stolonifer, resulted in the production of metabolites 3 and 4. While incubation of clerodane methyl ester (2) by R. stolonifer yielded metabolites 5–8. The structures of the transformed products were determined by the spectroscopic techniques and compounds 4, 7 and 8 were found. The antibacterial activity of clerodane diterpenoids 1 and 2 and their metabolites 3–8 were also studied. The metabolites 3–7 showed moderate activities against both Gram-positive and Gram-negative organisms. While metabolite 8 showed a moderate activity against Gram-positive organisms and a good activity against Gram-negative organisms.
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Transformation of clerodane lactone (1) and clerodane methyl ester (2) by Rhizopus stolonifer produced compound 4 and the isomeric pair 7 and 8, respectively. The metabolites showed moderate antibacterial activities against Gram-negative and positive bacteria.? Transformation of clerodane 1 and 2, by Rhizopus stolonifer, yielded metabolites 3–8. ? Metabolites 4, 7 and 8 were found to be new compound. ? Metabolite 8 showed a good activity against Gram-negative and positive bacteria.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Anna Wojakowska , Anna Piasecka , Pedro M. García-López , Francisco Zamora-Natera , Pawe? Krajewski , ?ukasz Marczak , Piotr Kachlicki , Maciej Stobiecki Flavonoid glycoconjugates from roots and leaves of eight North America lupine species (Lupinus elegans, Lupinus exaltatus, Lupinus hintonii, Lupinus mexicanus, Lupinus montanus, Lupinus rotundiflorus, Lupinus stipulatus, Lupinus sp.), three Mediterranean species (Lupinus albus, Lupinus angustifolius, Lupinus luteus) and one species from South America domesticated in Europe (Lupinus mutabilis) were analyzed using two LC/MS systems: low-resolution ion trap instrument and high-resolution quadrupole-time-of-flight spectrometer. As a result of the LC/MS profiling using the CID/MSn experiments structures of 175 flavonoid glycoconjugates found in 12 lupine species were identified at three confidence levels according to the Metabolomic Standard Initiative, mainly at level 2 and 3, some of them were classified to the level 1.Among the flavonoid derivatives recognized in the plant extracts were isomeric or isobaric compounds, differing in the degree of hydroxylation of the aglycones and the presence of glycosidic, acyl or alkyl groups in the molecules. The elemental composition of the glycoconjugate molecules was established from the exact m/z values of the protonated/deprotonated molecules ([M+H]+/[M?H]?) measured with the accuracy better than 5ppm. Information concerning structures of the aglycones, the type of sugar moieties (hexose, deoxyhexose or pentose) and, in some cases, their placement on the aglycones as well as the acyl substituents of the flavonoid glycoconjugates was achieved in experiments, in which collision-induced dissociation was applied. Flavonoid aglycones present in the studied O-glycoconjugates were unambiguously identified after the comparison of the pseudo-MS3 spectra with the spectra registered for the standards. Isomers of flavonoid glycoconjugates, in which one or two sugar moieties were attached to 4?- or 7-hydroxyl groups or directly to the C-6 or C-8 of the aglycones, could be distinguished on the basis of the MS2 spectra. However, the collision energy applied in the CID experiments had to be optimized for each group of the compounds and there were no universal settings that allowed the acquisition of structural information for all the compounds present in the sample.Information obtained from the flavonoid conjugate profiling was used for the chemotaxonomic comparison of the studied lupine species. A clear-cut discrimination of the Mediterranean and North American lupines was obtained as a result of this analysis.
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175 Isomeric and isobaric phenolic secondary metabolites of Mexican, North American and Mediterranean lupine species were annotated using CID/MS? experiments. On this basis chemotaxonomic analysis was conducted.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Dmitry V. Kochkin , Vadim V. Kachala , Alexander S. Shashkov , Alexander O. Chizhov , Vasily Y. Chirva , Alexander M. Nosov The presence of large amounts of ginsenosides malonyl-Rb1, -Rc, -Rb2, and -Rd in a suspension culture of Panax japonicus var. repens cells was demonstrated for the first time. Identification of ginsenoside malonyl-Rb1 was based on chromatographic, chemical, and spectroscopic evidence. Ginsenosides malonyl-Rc, -Rb2, and -Rd were identified on the basis of chromatographic and chemical data. Content and composition of the individual ginsenosides (Rg1, R0, malonyl-Rb1, Rb1, Rc, Rb2, and Rd) were monitored in the suspension culture over 4 years. The RP-HPLC-UV analysis showed that Rg1, R0, and malonyl-Rb1 accounted for more than 75% of the total pool of ginsenosides. In accordance with this result, and data analysis reported in the literature, we propose that ginsenoside formation in the cells of P. japonicus var. repens in vitro is closely related to the cellular compartmentation of these substances. In particular, the accumulation of the 20(S)-protopanaxadiol ginsenosides (especially Rb1) is strongly dependent on their pattern of malonylation, which likely targets them for transport into the vacuole.
Publication date: Available online 2 May 2013 Source:Phytochemistry Author(s): Rebecca E. Miller , Kellie L. Tuck The aromatic cyanogenic glycosides taxiphyllin [(R)-4-hydroxymandelonitrile ?-d-glucoside] and prunasin [(R)-mandelonitrile ?-d-glucoside] were identified as the main cyanogenic compounds in tissues of Australian endemic tropical rainforest tree taxa in the Lauraceae and Sapindaceae families, respectively. The tyrosine-derived taxiphyllin was the main cyanogenic glycoside in foliage of Beilschmiedia collina. This is the first reported cyanogenic compound from the Lauraceae. In addition, substantial quantitative variation in the capacity for cyanogenesis was detected in leaves from 40 individuals, with taxiphyllin concentrations ranging from 23 to 1263?g CN g?1 dry wt. No acyanogenic individuals were detected. Concentrations of taxiphyllin were, on average, 2.2-fold greater in young leaves than in old leaves. Prunasin was the dominant cyanogenic compound in tissues of Mischocarpus grandissimus (leaves) and Mischocarpus exangulatus (leaves and seed capsule). Better known for cyanolipids in seed oils, this is the first time a phenylalanine-derived cyanogenic glycoside has been reported in the Sapindaceae. The concentrations of prunasin varied widely, over an order of magnitude, among individuals and different tissue types in these species, with the higher concentrations found in seed capsules and young leaves.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Maria João Pimenta Lange , Anja Liebrandt , Linda Arnold , Sara-Miriam Chmielewska , André Felsberger , Eduard Freier , Monika Heuer , Doreen Zur , Theo Lange Cucurbits have been used widely to elucidate gibberellin (GA) biosynthesis. With the recent availability of the genome sequence for the economically important cucurbit Cucumis sativus, sequence data became available for all genes potentially involved in GA biosynthesis for this species. Sixteen cDNAs were cloned from root and shoot of 3-d to 7-d old seedlings and from mature seeds of C. sativus. Two cDNAs code for GA 7-oxidases (CsGA7ox1, and -2), five for GA 20-oxidases (CsGA20ox1, -2, -3, -4, and -5), four for GA 3-oxidases (CsGA3ox1, -2, -3, and -4), and another five for GA 2-oxidases (CsGA2ox1, -2, -3, -4, and -5). Their enzymatic activities were investigated by heterologous expression of the cDNAs in Escherichia coli and incubation of the cell lysates with 14C-labelled, D2-labelled, or unlabelled GA-substrates. The two GA 7-oxidases converted GA12-aldehyde to GA12 efficiently. CsGA7ox1 converted GA12 to GA14, to 15?-hydroxyGA12, and further to 15?-hydroxyGA14. CsGA7ox2 converted GA12 to its 12?-hydroxylated analogue GA111. All five GA 20-oxidases converted GA12 to GA9 as a major product, and to GA25 as a minor product. The four GA 3-oxidases oxidized the C19-GA GA9 to GA4 as the only product. In addition, three of them (CsGA3ox2, -3, and -4) converted the C20-GA GA12 to GA14. The GA 2-oxidases CsGA2ox1, -2, -3, and -4 oxidized the C19-GAs GA9 and GA4 to GA34 and GA51, respectively. CsGA2ox2, -3, and -4 converted GA51 and GA34 further to respective GA-catabolites. In addition to C19-GAs, CsGA2ox4 also converted the C20-GA GA12 to GA110. In contrast, CsGA2ox5 oxidized only the C20 GA12 to GA110 as the sole product. As shown for CsGA20ox1 and CsGA3ox1, similar reactions were catalysed with 13-hydroxlyated GAs as substrates. It is likely that these enzymes are also responsible for the biosynthesis of 13-hydroxylated GAs in vivo that occur at low levels in cucumber.
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Gibberellin (GA) hormones are powerful regulators of plant development. Sixteen genes encoding four different GA-oxidase families were cloned from the important crop cucumber, and their enzymatic functions were determined. The pathway drawn from the catalytic properties of these enzymes illustrate their potential for regulating GA-hormone homeostasis during cucumber development.? Sixteen putative GA-oxidases were identified in cucumber. ? Phylogenetic analysis distributed them into four groups (7-, 20-, 3-, and 2-oxidases). ? Members within the 7- and 2-oxidase groups have different enzymatic function. ? Members within the other two groups are functionally similar.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Eiji Ota , Wataru Tsuchiya , Toshimasa Yamazaki , Masatoshi Nakamura , Chikara Hirayama , Kotaro Konno Latex and other exudates in plants contain various proteins that are thought to play important defensive roles against herbivorous insects and pathogens. Herein, the defensive effects of phloem exudates against the Eri silkworm, Samia ricini (Saturniidae, Lepidoptera) in several cucurbitaceous plants were investigated. It was found that phloem exudates are responsible for the defensive activities of cucurbitaceous plants, such as the wax gourd Benincasa hispida and Cucumis melo, especially in B. hispida, whose leaves showed the strongest growth-inhibitory activity of all the cucurbitaceous plants tested. A 35kDa proteinaceous growth-inhibitory factor against insects designated BPLP (B. hispida Phloem Lectin-like Protein) was next isolated and purified from the B. hispida exudate, using anion exchange and gel filtration chromatography. A very low concentration (70?g/g) of BPLP significantly inhibited growth of S. ricini larvae. The full-length cDNA (1076bp) encoding BPLP was cloned and its nucleotide sequence was determined. The deduced amino acid sequence of BPLP had 51% identity with a cucurbitaceous phloem lectin (phloem protein 2, PP2), and showed binding specificity to oligomers of N-acetylglucosamine. Some features of BPLP indicated that it does not have a cysteine residue and it is composed of two repeats of similar sequences, suggesting that BPLP is distinct from PP2. Recombinant BPLP, obtained by expressing the cDNA in Escherichia coli, showed both chitin-binding lectin activity and growth-inhibitory activity against S. ricini larvae. The present study thus provides experimental evidence that phloem exudates of Cucurbitaceae plants, analogous to plant latex, play defensive roles against insect herbivores, especially against chewing insects, and contain defensive substances toxic to them.
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A 35kDa anti-insect defense protein designated BPLP (Benincasa hispida phloem Lectin-like protein) was purified from the phloem exudate of the wax gourd, Benincasa hispida, and the encoding gene was cloned.? BPLP, a defense protein, was purified from the phloem exudate of wax gourd. ? BPLP is highly toxic to lepidopteran larvae at 0.007% concentration of a wet diet. ? The gene encoding BPLP was cloned and the amino acid sequence of BPLP was determined. ? The amino acid sequence of BPLP is similar to, but distinct from, those of phloem protein 2. ? Anti-insect defensive roles of phloem exudates and components were established.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Lorenzo Del Terra , Valentina Lonzarich , Elisa Asquini , Luciano Navarini , Giorgio Graziosi , Furio Suggi Liverani , Alberto Pallavicini The chemical composition of the coffee beverage is extremely complex, being made up of hundreds of volatile and non-volatile compounds, many of which are generated in the thermal reactions that occur during the roasting process. However, in the raw coffee bean there are also compounds that survive roasting and are therefore extracted into the beverage. Monoterpenes are an example of this category, as their presence has been reported in the coffee flower, fruit, seed, roasted bean and in the beverage aroma.The present work describes the isolation, heterologous expression and functional characterization of three Coffea arabica cDNAs coding for monoterpene synthases. RNA was purified from C. arabica (cv. Catuai Red) flowers, seeds and fruits at 4 successive ripening stages. Degenerate primers were designed on the most conserved regions of the monoterpene synthase gene family, and then used to isolate monoterpene synthase-like sequences from the cDNA libraries. After 5?- and 3?-RACE, the complete transcripts of 4 putative C. arabica monoterpene synthases (CofarTPS) were obtained. Gene expression in different tissues and developmental stages was analysed. After heterologous expression in Escherichia coli, enzyme activity and substrate specificity were evaluated in vitro by incubation of the recombinant proteins with geranyl pyrophosphate (GPP), geranylgeranyl pyrophosphate (GGPP) and farnesyl pyrophosphate (FPP), precursors respectively of mono-, di- and sesquiterpenes. The reaction products were characterized by HS-SPME GC–MS. CofarTPS1 was classified as a limonene synthase gene, while CofarTPS2 and 3 showed lower activity with the production of linalool and ?-myrcene.
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A limonene synthase and two linalool/myrcene synthases have been isolated from Coffea arabica and functionally characterized in vitro after recombinant protein expression and purification.? We report the isolation of terpene synthase genes from Coffea arabica. ? Three recombinant proteins are functionally characterized as monoterpene synthases. ? Tissue specificity and cladistic data are presented. ? One of the proteins produces limonene, one of the main monoterpenes in coffee aroma.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Olivier Habrylo , Anne Forster , Jean-Marc Jeltsch , Vincent Phalip Phytopathogenic fungi secrete a powerful arsenal of enzymes that are potentially active against each polysaccharide component of the plant cell wall. To defend themselves, plants synthetise a variety of molecules that inhibit the activity of cell wall-degrading enzymes. Xyloglucan-specific endoglucanase inhibitor proteins (XEGIPs) act specifically against the members of fungal glycoside hydrolase family 12 (GH12 in the CAZy database). In the present study, we describe the identification of three XEGIP homologues from hop (Humulus lupulus L.). When incubating each of the recombinant inhibitors with an enzymatic cocktail from Aspergillus aculeatus (Viscozyme®), the xyloglucan-degrading endoglucanase activity decreased to 15% and 5% for HlXEGIP1 and HlXEGIP2, respectively, whereas no inhibition of the Viscozyme® enzymes was observed for the third (also called HlXEGIP homologue 3, or HlXEGIPh3). Fungal enzymatic cocktails from 20 different species also showed xyloglucan-degrading endoglucanase activities, and most of them were inhibited by HlXEGIP1 and -2. Furthermore, a real time RT-PCR analysis revealed variations in the spatial distribution of the genes encoding the three inhibitors and differential expression during development and (a) biotic stress. The role of XEGIPs in the plant-fungus interaction is discussed, and a model suggesting a distinct role of these XEGIP homologues is proposed: HlXEGIP1 may act in cases of abiotic stress, while HlXEGIP2 reacts to biotic stress, and physiological development may be influenced by HlXEGIPh3.
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Proposed model for the role of xyloglucanase inhibitor homologues in hop. HlXEGIP1 may act in case of abiotic stress and also during biotic stress, as well HlXEHGIP2. Inhibitions of glycosyl hydrolases family 12 are shown. Physiological development may be influenced by HlXEGIPh3.? Three xyloglucanase inhibitors were identified and functionally described in hop. ? The three corresponding genes were differently expressed in response to stresses. ? One of them allowed xyloglucanase inhibition towards 17 fungi enzyme cocktails. ? A model proposing a different role for the three inhibitors is proposed.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Kiyoshi Ohyama , Akiko Okawa , Yuka Moriuchi , Yoshinori Fujimoto The C-26 amino group of steroidal alkaloids, such as tomatine, is introduced during an early step of their biosynthesis from cholesterol. In the present study, the mechanism of C-26 amination was reinvestigated by administering stable isotope labeled compounds, such as (26,26,26,27,27,27-2H6)cholesterol during biosynthesis of tomatine, solanine and solasonine. The chemical compositions of tomatine and solanine so obtained were analyzed by LC–MS after administering the d6-cholesterol to a tomato seedling and a potato shoot, respectively. The resulting spectra indicated that two deuterium atoms were eliminated from C-26 of cholesterol during biosynthesis. Furthermore, administration of (6-13C2H3)mevalonate in combination with lovastatin to an eggplant seedling, followed by GC–MS analysis of solasodine after TMS derivatization established that two deuterium atoms were eliminated from C-26 of cholesterol during solasonine biosynthesis. These findings are in contrast to an earlier observation that one hydrogen atom was lost from C-26 during tomatidine biosynthesis, and suggest that C-26 nitrogen atom addition involves an aldehyde intermediate. Thus, it is proposed that the C-26 amination reaction that occurs during steroidal alkaloid biosynthesis proceeds by way of a transamination mechanism.
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Highlights
Elimination of two hydrogen atoms from C-26 of cholesterol during the biosynthesis of tomatine, solanine, chaconine and solasonine suggest a transamination mechanism for the C-26 amination.? Mechanism of C-26 amination during steroidal alkaloid biosynthesis was investigated. ? Deuterium labeled cholesterol and mevalonate were administered to Solanum lycopersicum, Solanum tuberosum and Solanum melongena. ? Two hydrogen atoms were eliminated from C-26 of cholesterol during steroidal alkaloid biosynthesis. ? It is proposed that the C-26 amination reaction proceeds via a transamination mechanism.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Faith E. Bartz , Norman J. Glassbrook , David A. Danehower , Marc A. Cubeta The metabolic control of plant growth regulator production by the plant pathogenic fungus Rhizoctonia solani Kühn (teleomorph=Thanatephorus cucumeris (A.B. Frank) Donk) and consequences associated with the parasitic and saprobic activity of the fungus were investigated. Fourteen genetically distinct isolates of the fungus belonging to anastomosis groups (AG) AG-3, AG-4, and AG-1-IA were grown on Vogel’s minimal medium N with and without the addition of a 25mM quinic acid (QA) source of carbon. The effect of QA on fungal biomass was determined by measuring the dry wt of mycelia produced under each growth condition. QA stimulated growth of 13 of 14 isolates of R. solani examined. The production of phenylacetic acid (PAA) and the chemically related derivatives 2-hydroxy-PAA, 3-hydroxy-PAA, 4-hydroxy-PAA, and 3-methoxy-PAA on the two different media was compared by gas chromatography coupled with mass spectrometry (GC–MS). The presence of QA in the growth medium of R. solani altered the PAA production profile, limiting the conversion of PAA to derivative forms. The effect of QA on the ability of R. solani to cause disease was examined by inoculating tomato (Solanum lycopersicum L.) plants with 11 isolates of R. solani AG-3 grown on media with and without the addition of 25mM QA. Mean percent survival of tomato plants inoculated with R. solani was significantly higher when the fungal inoculum was generated on growth medium containing QA. The results of this study support the hypotheses that utilization of QA by R. solani leads to reduced production of the plant growth regulators belonging to the PAA metabolic complex which can suppress plant disease development.
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Metabolic control of plant growth regulator production in the plant pathogenic fungus Rhizoctonia solani by quinic acid leads to increased survival of inoculated tomato plants.? Plant growth regulator production by Rhizoctonia solani was investigated by GC–MS and bioassay. ? Quinic acid limited the conversion of phenylacetic acid to derivative forms by R. solani. ? Tomato plant survival was higher when R. solani inoculum was grown on medium containing quinic acid.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Braulio M. Fraga , Victoria González-Vallejo , Ricardo Guillermo , Juan M. Amaro-Luis The incubation of 15?-hydroxy-ent-kaur-9(11),16-dien-19-oic acid (15?-hydroxy-grandiflorenic acid) with the fungus Fusarium fujikuroi gave as main metabolite its 3?,6?-dihydroxy derivative, which by an oxidative decarboxylation afforded a 19-nor compound with a 4,18-double bond. Other substances obtained were a 3?-hydroxy-19,6?-lactone, 3?-hydroxy-6?,7?-epoxy-ent-kaur-9(11),16-dien-19-oic acid and 3?-hydroxy-6-oxo-ent-kaur-9(11),16-dien-19-oic acid. Moreover, the biotransformation of 15?,18-dihydroxy-ent-kaur-9(11),16-diene led to the isolation of the corresponding 3?-, 6?-, 7?- and 12?-hydroxy derivatives. Two metabolites formed by 16?,17-epoxidation of the last compound and of the substrate were also obtained. These results indicated that the presence of the 9,11-double bond in the substrate impedes its 7?-hydroxylation, which is necessary for the formation of gibberellins and seco-ring B ent-kaurenoids. However, this 9,11-unsaturation does not hinder a 6,7-dehydrogenation and further 6?,7?-epoxidation, characteristic steps of the kaurenolide biosynthetic pathway.
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Incubation of 15?-hydroxy-grandiflorenic acid (4) with Fusarium fujikuroi gave its 3?,6?-dihydroxy-, 3?-hydroxy-6?,7?-epoxy- and 3?-hydroxy-6-oxo-derivatives, together with a 19-nor compound and a 3?-hydroxy-19,6?-lactone. In addition, the biotransformation of 15?,18-dihydroxy-ent-kaur-9(11),16-diene led to the isolation of its 3?-, 6?-, 7?- and 12?-hydroxy-derivatives.? Biotransformation of ent-kaur-9(11),16-diene derivatives by Fusarium fujikuroi. ? Inhibition of the biosynthesis of gibberellins and seco-ring B ent-kaurenoids. ? Decarboxylation of a 19-CO2H in presence of a 6?-hydroxy group in ent-kaurenes. ? On the incubation of grandiflorenic acid with Fusarium fujikuroi.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Matthieu Gaucher , Thomas Dugé de Bernonville , David Lohou , Sylvain Guyot , Thomas Guillemette , Marie-Noëlle Brisset , James F. Dat Flavonoids, like other metabolites synthesized via the phenylpropanoid pathway, possess a wide range of biological activities including functions in plant development and its interaction with the environment. Dihydrochalcones (mainly phloridzin, sieboldin, trilobatin, phloretin) represent the major flavonoid subgroup in apple green tissues. Although this class of phenolic compounds is found in very large amounts in some tissues (?200mg/g of leaf DW), their physiological significance remains unclear. In the present study, we highlight their tissue-specific localization in young growing shoots suggesting a specific role in important physiological processes, most notably in response to biotic stress. Indeed, dihydrochalcones could constitute a basal defense, in particular phloretin which exhibits a strong broad-range bactericidal and fungicidal activity. Our results also indicate that sieboldin forms complexes with iron with strong affinity, reinforcing its antioxidant properties and conferring to this dihydrochalcone a potential for iron seclusion and/or storage. The importance of localization and biochemical properties of dihydrochalcones are discussed in view of the apple tree defense strategy against both biotic and abiotic stresses.
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The histolocalization of dihydrochalcones in various green tissues of Malus x domestica was investigated together with their antimicrobial and iron-chelating activities. The physiological roles of this major subgroup of flavonoids in apple tree are proposed.? Easy staining methods for dihydrochalcone location in apple tissues are proposed. ? Dihydrochalcones localize in upper layers of leaves and around vascular bundles. ? Phloretin shows a high antimicrobial activity against a broad spectrum of microbes. ? The o-diphenol sieboldin is a potent iron-chelator.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Abhishek Sahu , Imran Pancha , Deepti Jain , Chetan Paliwal , Tonmoy Ghosh , Shailesh Patidar , Sourish Bhattacharya , Sandhya Mishra Microalgae are primary producers of the food chain and hold prominence towards pharmaceutical and nutraceutical applications. Fatty acids (FAs) are one of the primary metabolites of microalgae, which enrich their utility both in the form of food and fuels. Additionally, the vast structural diversity coupled with taxonomic specificity makes these FAs as potential biomarkers. The determination of lipid and fatty acid profiling of 12 different strains of microalgae has been accomplished in this study and further discussed in respect to their chemotaxonomic perspective in microalgae. Palmitic acid (C16:0) and oleic acid (C18:1n9c) were found to be dominant among the members of Cyanophyceae whereas members of Chlorophyceae were rich in palmitic acid (C16:0), oleic acid (C18:1n9c) and linoleic acid (C18:2n6). The application of principal component analysis (PCA) and algorithmic hierarchical clustering (AHC) resulted in the segregation of the studied microalgal strains into 8 different orders belonging to 2 distinct phyla according to their phylogenetic classification. Nutritionally important FAs like eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) were detected only in Chlorella sp. belonging to Chlorophyceaen family. Differential segregation of microalgae with respect to their fatty acid profile indicated the potential utility of FAs as biomarkers.
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C16:0 (A) and C18:1n9c (B) are the most abundant fatty acids in microalgae. PCA and AHC study of the 12 microalgal strains, segregated into 2 different phyla belonging to 8 distinct taxonomic orders.? Lipid–fatty acid profiling of 12 microalgal strains belonging to 2 distinct phyla were done. ? Palmitic acid (C16:0) and oleic acid (C18:1n9c) are the most abundant fatty acids. ? Cyanophyceae members are found to have higher unsaturation index. ? Chemotaxonomic relationship of fatty acid variables have been done by using PCA and AHC. ? Chlorophyceae and Cyanophyceae members are clustered with distinct taxonomic orders.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Wen-Chun Lan , Cheng-Wei Tzeng , Chun-Ching Lin , Feng-Lin Yen , Horng-Huey Ko Flavonoids, 10-oxoartogomezianone (1), 8-geranyl-3-(hydroxyprenyl)isoetin (2), hydroxyartoflavone A (3), isocycloartobiloxanthone (4), and furanocyclocommunin (5), together with 12 known compounds, were isolated from heartwood and cortex of Artocarpus altilis, and their structures were identified by comparing their spectra with those of similar compounds. To identify natural antioxidants and whitening agents, the ability of these prenylated flavonoids was assessed to scavenge the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), the 2,2?-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) radical cation, and the superoxide anion (O2?), and their abilities to inhibit tyrosinase and melanin production. It was found that compounds 3, 4, and artoflavone A (15) had moderate DPPH-scavenging activity, whereas compound 4 exhibited significant ABTS+-scavenging activity, and that norartocarpetin (7) and artogomezianone (8) exhibited moderate ABTS+-scavenging activity, with compounds 2, 7, and artocarpin (6) displaying good superoxide anion-scavenging activity. In addition, compounds 7, 8, cudraflavone A (14), and artonin M (17), inhibited melanin production by strongly suppressing tyrosinase activity. Compound 6 reduced the melanin content without inhibiting tyrosinase activity. These results suggest that flavonoids isolated from A. altilis may be candidate antioxidants and/or skin-whitening agents. However, further investigations are required to determine their mechanisms of action.
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Compounds 1–5, together with 12 known compounds, were isolated from the heartwood and cortex of Artocarpus altilis. Several of these showed free radical scavenging activity, and some reduced melanin production without affecting cell viability. These compounds could be considered as cosmetic agents in the future.? Five flavonoids, and 12 known compounds, were isolated from Artocarpus altilis. ? Natural antioxidants and tyrosinase inhibitors of A. altilis were identified. ? The inhibition modes of active compounds on tyrosinase were identified. ? Some prenylated flavones were demonstrated to reduce melanin production.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Ebenézer de Mello Cruz , Edson Roberto da Silva , Claudia do Carmo Maquiaveli , Eliomara Sousa Sobral Alves , João Francisco Lucon Jr. , Matheus Balduino Gonçalves dos Reis , Cleyton Eduardo Mendes de Toledo , Frederico Guaré Cruz , Marcos André Vannier-Santos The plant Cecropia pachystachya Trécul is widely used in Brazilian ethnomedicine to treat hypertension, asthma, and diabetes. Arginase is an enzyme with levels that are elevated in these disorders, and it is central to Leishmania polyamine biosynthesis. The aims of this study were to evaluate antileishmanial activity and inhibition of the arginase enzyme by C. pachystachya extracts, and to study changes in cellular organization using electron microscopy. The ethanol extract of C. pachystachya was tested on Leishmania (Leishmania) amazonensis promastigote survival/proliferation and arginase activity in vitro. Qualitative ultrastructural analysis was also used to observe changes in cell organization. The major bioactive molecules of the ethanol extract were characterized using liquid chromatography–electrospray ionization-mass spectrometry (LC–ESI-MS). The ethyl acetate fraction of the ethanol extract diminished promastigote axenic growth/survival, inhibited arginase activity, and altered a mitochondrial kinetoplast DNA (K-DNA) array. The bioactive compounds of C. pachystachya were characterized as glucoside flavonoids. Orientin (9) (luteolin-8-C-glucoside) was the main component of the methanol-soluble ethyl acetate fraction obtained from the ethanol extract and is an arginase inhibitor (IC50 15.9?M). The ethyl acetate fraction was not cytotoxic to splenocytes at a concentration of 200?g/mL. In conclusion, C. pachystachya contains bioactive compounds that reduce the growth of L. (L.) amazonensis promastigotes, altering mitochondrial K-DNA arrangement and inhibiting arginase.
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Inhibition of arginase blocks the first step of the synthesis of polyamines that are essential for the multiplication and maintenance of the antioxidant mechanism through synthesis of trypanothione.? Cecropia pachystachya contains anti-leishmanial flavonoids. ? Flavonoids altered mitochondrial DNA arrangements. ? Flavonoids are strong inhibitors of arginase. ? Orientin (luteolin-8-C-glucoside) show an IC50 of 16?M for arginase inhibition.
Publication date: June 2013 Source:Phytochemistry, Volume 90 Author(s): Klaudia Michalska , Edward Szneler , Wanda Kisiel A total of 19 sesquiterpene lactones were isolated from roots of Lactuca canadensis L., of which 10 were reported for the first time from Lactuca species and two were unknown. This is also the first report on the co-occurrence of three pairs of zaluzanin C-type guaianolides, epimeric at C-3, and on the presence of six eudesmanolides, oxygenated at C-1 and C-3, in Lactuca species. The new compounds were characterized as 3-epizaluzanin C-3-O-?-glucopyranoside and 11,13-dehydrolactuside C using 1D and 2D NMR and high resolution mass spectroscopy. The sesquiterpene lactone profile of this species is dominated by zaluzanin C-type guaianolides (9 compounds) and eudesmanolides (8 compounds). The dissimilarity of this profile compared to that of other taxa of the genus is discussed.
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Roots of the plant afforded 19 sesquiterpene lactones, including two new compounds (1 and 2), and 10 compounds found for the first time in Lactuca species.? A total of 19 sesquiterpene lactones have been isolated. ? Zaluzanin C-type guaianolides and eudesmanolides predominate. ? Two compounds are new natural products. ? Ten known compounds have no precedent in Lactuca species.
Publication date: May 2013 Source:Phytochemistry, Volume 89 Author(s): Wen-Xuan Wang , Juan Xiong , Yu Tang , Jing-Jing Zhu , Ming Li , Yun Zhao , Guo-Xun Yang , Gang Xia , Jin-Feng Hu The roots of the medicinal ornamental plant Clerodendrum trichotomum yielded a series of rearranged abietane diterpenoids, including three 17(15?16)-abeo-abietane (1–3) and three 17(15?16),18(4?3)-diabeo-abietane (4–6) derivatives. Their structures were elucidated by means of spectroscopic methods. The absolute configuration of (10R,16R)-12,16-epoxy-11,14,17-trihydroxy-6-methoxy-17(15?16)-abieta-5,8,11,13-tetraene-7-one (1) was deduced by a combination of single crystal X-ray diffraction analysis and the observed Cotton effects in its circular dichroism (CD) spectrum. All isolates were tested for their cytotoxicities against five human cancer cell lines (BGC-823, Huh-7, KB, KE-97, and Jurkat). Among them, compounds 4, 6, 9, 10, 12, and 14, each possessing a common 17(15?16),18(4?3)-diabeo-abietane framework, were found to have remarkable cytotoxic effects with IC50 values ranging from 0.83 to 50.99?M.
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Rearranged abietane diterpenoids (1–6) were isolated from the roots of Clerodendrum trichotomum. The absolute configuration of compound 1 was completely deduced. Compounds 4, 6, 9, 10, 12, and 14, each possessing a common 17(15?16),18(4?3)-diabeoabietane framework, exhibited remarkable cytotoxic effects against a small panel of human cancer cell lines.?Rearranged abietane diterpenoids were isolated from Clerodendrum trichotomum. ? The absolute configuration of compound 1 was ascertained. ? Compound 6 possessed a rare 3,4-epoxy moiety in its structure. ? Some isolates exhibited remarkable cytotoxic effects against human cancer cells.
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