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Journal of Natural Products

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https://www.readbyqxmd.com/read/29461846/ca-2-signal-transduction-inhibitors-kujiol-a-and-kujigamberol-b-isolated-from-kuji-amber-using-a-mutant-yeast
#1
Takeshi Uchida, Hiroyuki Koshino, Shunya Takahashi, Eisaku Shimizu, Honoka Takahashi, Jun Yoshida, Hisao Shinden, Maiko Tsujimura, Hisayoshi Kofujita, Shota Uesugi, Ken-Ichi Kimura
A podocarpatriene and a labdatriene derivative, named kujiol A [13-methyl-8,11,13-podocarpatrien-19-ol (1)] and kujigamberol B [15,20-dinor-5,7,9-labdatrien-13-ol (2)], respectively, were isolated from Kuji amber through detection with the aid of their growth-restoring activity against a mutant yeast strain (zds1Δ erg3Δ pdr1Δ pdr3Δ), which is known to be hypersensitive with respect to Ca2+ -signal transduction. The structures were elucidated by spectroscopic data analysis. Compounds 1 and 2 are rare organic compounds from Late Cretaceous amber, and the mutant yeast used seems useful for elucidating a variety of new compounds from Kuji amber specimens, produced before the K-Pg boundary...
February 20, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29461824/resolving-the-19r-absolute-configuration-of-lanciferine-a-monoterpene-indole-alkaloid-from-alstonia-boulindaensis
#2
Mehdi A Beniddir, Grégory Genta-Jouve, Guy Lewin
Reinvestigation of the structure of lanciferine (1a) through extensive spectroscopic analysis in conjunction with a detailed computational study led to the unambiguous assignment of its (19R) absolute configuration, thus leading to the full (2R, 3S, 7S, 15R, 16R, 19R, 20S) assignment of lanciferine 45 years after its isolation.
February 20, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29451791/correction-to-eudesmane-sesquiterpenes-from-verbesina-lanata-with-inhibitory-activity-against-grapevine-downy-mildew
#3
Justine Ramseyer, Barbara Thuerig, Maria De Mieri, Hans-Jakob Schärer, Thomas Oberhänsli, Mahabir P Gupta, Lucius Tamm, Matthias Hamburger, Olivier Potterat
No abstract text is available yet for this article.
February 16, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29442505/concise-total-synthesis-of-%C3%A2-deguelin-and-%C3%A2-tephrosin-using-a-vinyl-iodide-as-a-key-building-block
#4
Shengtao Xu, Guangyu Wang, Feijie Xu, Wenlong Li, Aijun Lin, Hequan Yao, Jinyi Xu
A concise and protecting-group-free total synthesis of the antiproliferative natural product (±)-deguelin (2) was accomplished in four steps and 62% overall yield from commercially available precursors. The key transformation employed a vinyl iodide as the pivotal building block to construct the 4-acylchromene substructure present in deguelin. Subsequent Cu2O-mediated α-hydroxylation of deguelin (2) afforded tephrosin (3) in 90% yield.
February 14, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29432010/cybastacines-a-and-b-antibiotic-sesterterpenes-from-a-nostoc-sp-cyanobacterium
#5
Alfredo H Cabanillas, Víctor Tena Pérez, Santiago Maderuelo Corral, Diego Fernando Rosero Valencia, Antera Martel Quintana, Montserrat Ortega Doménech, Ángel Rumbero Sánchez
Cybastacines A (1) and B (2) were discovered as a novel pentacyclic sesterterpenoid-alkaloid skeleton structure, with a guanidinium group. These molecules were isolated from a Nostoc sp. cyanobacterium collected in the Canary Islands. Their structures were elucidated primarily by a combination of spectroscopic analyses and X-ray diffraction. These compounds showed antibiotic activities against several clinically relevant bacterial strains.
February 12, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29431450/advanced-nmr-based-structural-investigation-of-glucosinolates-and-desulfoglucosinolates
#6
Nada Ibrahim, Ingrid Allart-Simon, Gina R De Nicola, Renato Iori, Jean-Hugues Renault, Patrick Rollin, Jean-Marc Nuzillard
Glucosinolates (GLs) constitute a class of plant secondary metabolites that are characteristic of the order Brassicales. They each contain a common hydrophilic moiety connected to a mostly hydrophobic side chain whose constitution is the most frequent structural variant. Their transformations by myrosinases lead to intensively studied and highly reactive compounds of biological relevancy. In other respects, the enzymatic desulfation of GLs produces derivatives (DS-GLs) that are useful for GL analysis. A collection of 31 compounds, GLs and DS-GLs, representing 17 different side chains was established in order to report accurate descriptions of the molecules' 1H-, 13C-, and 15N-NMR parameters...
February 12, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29431439/marine-invertebrate-natural-products-that-target-microtubules
#7
John H Miller, Jessica J Field, Arun Kanakkanthara, Jeremy G Owen, A Jonathan Singh, Peter T Northcote
Marine natural products as secondary metabolites are a potential major source of new drugs for treating disease. In some cases, cytotoxic marine metabolites target the microtubules of the eukaryote cytoskeleton for reasons that will be discussed. This review covers the microtubule-targeting agents reported from sponges, corals, tunicates, and molluscs and the evidence that many of these secondary metabolites are produced by bacterial symbionts. The review finishes by discussing the directions for future development and production of clinically relevant amounts of these natural products and their analogues through aquaculture, chemical synthesis, and biosynthesis by bacterial symbionts...
February 12, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29412669/modified-abietane-diterpenoids-from-whole-plants-of-selaginella-moellendorffii
#8
Lei-Yu Ke, Yu Zhang, Meng-Yuan Xia, Jing-Xian Zhuo, Yue-Hu Wang, Chun-Lin Long
A new modified abietane diterpenoid, (3S,4S,5R,10S)-18(4→3)-abeo-3,4,12,18-tetrahydroxy-8,11,13-abietatrien-7-one (1), and two novel dimers, selaginedorffones A (2) and B (3), featuring a new cyclohexene moiety that was biogenetically constructed from two modified abietane diterpenoids through a Diels-Alder reaction were obtained from a methanolic extract of Selaginella moellendorffii, a traditional Chinese herb. The structures of 1-3 were identified by a combination of NMR spectroscopic analysis and ECD calculations...
February 7, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29406734/capsicodendrin-from-cinnamosma-fragrans-exhibits-antiproliferative-and-cytotoxic-activity-in-human-leukemia-cells-modulation-by-glutathione
#9
Soumendrakrishna Karmahapatra, Corey Kientz, Shruthi Shetty, Jack C Yalowich, L Harinantenaina Rakotondraibe
Capsicodendrin (CPCD, 1), an epimeric mixture of a dimeric drimane-type sesquiterpene, is one of the major compounds present in the three endemic species of Madagascan traditional chemopreventive plants: Cinnamosma species (C. fragrans, C. macrocarpa, and C. madagascariensis). Despite the popular use of Cinnamosma in Madagascan traditional medicine and the reported antiproliferative properties of CPCD, elucidation of its mechanism(s) of action is still to be accomplished. In the present study, CPCD at low micromolar concentrations was cytotoxic and induced apoptosis in human myeloid leukemia cells in a time- and concentration-dependent manner...
February 6, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29406718/metabolomics-analysis-reveals-that-ethylene-and-methyl-jasmonate-regulate-different-branch-pathways-to-promote-the-accumulation-of-terpenoid-indole-alkaloids-in-catharanthus-roseus
#10
Xiao-Ning Zhang, Jia Liu, Yang Liu, Yu Wang, Ann Abozeid, Zhi-Guo Yu, Zhong-Hua Tang
The medicinal plant Catharanthus roseus accumulates large numbers of terpenoid indole alkaloids (TIAs), including the pharmaceutically important vinblastine, vincristine, ajmalicine, and serpentine. The phytohormone ethylene or methyl jasmonate (MeJA) can markedly enhance alkaloid accumulation. The interaction between ethylene or MeJA in the regulation of TIA biosynthesis in C. roseus is unknown. Here, a metabolomics platform is reported that is based on liquid chromatography (LC) coupled with time-of-flight mass spectrometry to study candidate components for TIA biosynthesis, which is controlled by ethylene or MeJA in C...
February 6, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29405714/metabolomics-guided-discovery-of-microginin-peptides-from-cultures-of-the-cyanobacterium-microcystis-aeruginosa
#11
Allison K Stewart, Rudravajhala Ravindra, Ryan M Van Wagoner, Jeffrey L C Wright
We report a mass-spectrometry-based metabolomics study of a laboratory-cultured strain of Microcystis aeruginosa (UTEX LB2385), which has led to the discovery of five peptides (1-5) belonging to the microginin class of linear cyanopeptides. The structures and configurations of these peptides were determined by spectroscopic analyses and chemical derivitization. The microginin peptides described herein are the first reported derivatives containing N-methyl methionine (1, 5) and N-methyl methionine sulfoxide (2-4)...
February 6, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29400966/mucroniferanines-a-g-isoquinoline-alkaloids-from-corydalis-mucronifera
#12
Jun Zhang, Qing-Ying Zhang, Peng-Fei Tu, Fu-Chun Xu, Hong Liang
Five pairs of isoquinoline alkaloid enantiomers, mucroniferanines A-E (1-5), two inseparable epimeric pairs, mucroniferanines F and G (6, 7), and 10 known isoquinoline alkaloids (8-17) were obtained from Corydalis mucronifera. The structures were characterized using spectroscopic data analysis, and the absolute configurations were established by ECD and X-ray data analysis. The new compounds except for 3 possess a rare 9-methyl group in the isoquinoline alkaloids, and compounds 2 and 3 possess rare benzo[1,2-d:3,4-d]bis[1,3]dioxole moieties...
February 5, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29400964/total-synthesis-of-scytonemide-a-employing-weinreb-am-solid-phase-resin
#13
Tyler A Wilson, Robert J Tokarski, Peter Sullivan, Robert M Demoret, Jimmy Orjala, L Harinantenaina Rakotondraibe, James R Fuchs
The human 20S proteasome inhibitor scytonemide A (1), a macrocyclic imine originally isolated from the cyanobacterium Scytonema hofmanni, was synthesized via a biomimetic solid-phase peptide synthesis (SPPS) approach employing the Weinreb AM resin. Utilizing this approach, cyclization of the protected heptapeptide via formation of the imine bond occurred spontaneously upon cleavage from the resin in the presence of a reducing agent and subsequent aqueous workup. The final deprotection step necessary to produce the natural product was accomplished under slightly basic conditions, facilitating cleavage of the silyl ether group while leaving the macrocycle intact...
February 5, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29400471/highly-oxidized-guaianolide-sesquiterpenoids-with-potential-anti-inflammatory-activity-from-chrysanthemum-indicum
#14
Gui-Min Xue, Xiao-Qing Li, Chen Chen, Kang Chen, Xiao-Bing Wang, Yu-Cheng Gu, Jian-Guang Luo, Ling-Yi Kong
Ten new highly oxidized monomeric (1-8) and dimeric guaianolides (9 and 10), along with two known guaianolide derivatives (11 and 12), were isolated from the aerial parts of Chrysanthemum indicum using a bioassay-guided fractionation procedure. The new compounds were characterized by the basic analysis of the spectroscopic data obtained, and the absolute configurations were determined by both empirical approaches and ECD calculations. Inhibitory effects of 1-12 on nitric oxide production were investigated in lipopolysaccaride (LPS)-mediated RAW 264...
February 5, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29400468/structurally-diverse-cytotoxic-dimeric-chalcones-from-oxytropis-chiliophylla
#15
Yang Liu, Xiaojing Zhang, Norbo Kelsang, Guangzhong Tu, Dexin Kong, Jianghai Lu, Yingtao Zhang, Hong Liang, Pengfei Tu, Qingying Zhang
Ten isomeric cyclobutane- and cyclohexene-containing chalcone dimers, oxyfadichalcones A-G, were isolated from the aerial parts of Oxytropis chiliophylla. These included six new compounds and three pairs of enantiomers that are being reported from natural sources for the first time. The relative configurations were elucidated by spectroscopic data analysis, while the absolute configurations were determined by comparing the experimental and calculated electronic circular dichroism spectra. Quantitative LC-MS analysis of the main dimers from different parts of the plant revealed their characteristic accumulation in the viscous secretion and provided supporting evidence for the hypothesized photochemical biosynthesis...
February 5, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29400463/peloruside-a-induced-cell-death-in-hypoxia-is-p53-dependent-in-hct116-colorectal-cancer-cells
#16
Jiří Řehulka, Narendran Annadurai, Ivo Frydrych, Petr Džubák, John H Miller, Marián Hajdúch, Viswanath Das
HCT116 colorectal cancer cell sensitivity to peloruside A (PLA) in normoxia is not altered by hypoxia preconditioning of the cells. We examined whether the PLA effects were altered in hypoxia and whether the activity was dependent on p53. The cytotoxicity of PLA in wild-type HCT116 cells was largely unaffected by hypoxia; however, cells in which p53 was knocked out showed resistance. Knockout of the p21 gene had little effect on the activity of PLA in hypoxia. It was concluded that the response of cells to the microtubule-stabilizing agent PLA under hypoxic conditions is a p53-dependent process...
February 5, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29397715/crispenes-f-and-g-cis-clerodane-furanoditerpenoids-from-tinospora-crispa-inhibit-stat3-dimerization
#17
Md Abdullah Al Noman, Tasnova Hossain, Monira Ahsan, Shirin Jamshidi, Choudhury Mahmood Hasan, Khondaker Miraz Rahman
Two new cis-clerodane-type furanoditerpenes, crispenes F and G (1 and 2), together with seven known compounds, were isolated from the stems of Tinospora crispa. Crispenes F and G (1 and 2) inhibited STAT3 dimerization in a cell-free fluorescent polarization assay and were found to have significant cytotoxicity against a STAT3-dependent MDA-MB 231 breast cancer cell line, while being inactive in a STAT3-null A4 cell line. These two compounds share structural similarities with a previously reported STAT3 inhibitor, crispene E, isolated from the same plant...
February 3, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29394065/total-synthesis-of-the-flavonoid-natural-product-houttuynoid-a
#18
Jie Jian, Jilin Fan, Hui Yang, Ping Lan, Manmei Li, Peijun Liu, Hao Gao, Pinghua Sun
The first total synthesis of the antiviral flavonoid houttuynoid A (1) has been achieved from aryl ketone 6 and benzofuran aldehyde 5 in nine linear steps. The C6-C3-C6 structure of the flavonoid was synthesized by an I2-catalyzed oxa-Michael addition of a chalcone intermediate, generated by the Claisen-Schmidt condensation of 5 and 6. This work provides a method for the synthesis of houttuynoids and provides a reference for the synthesis of the remaining members of the houttuynoid family.
February 2, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29394063/anti-influenza-triterpene-saponins-from-the-bark-of-burkea-africana
#19
Christina E Mair, Ulrike Grienke, Anke Wilhelm, Ernst Urban, Martin Zehl, Michaela Schmidtke, Judith M Rollinger
In an in vitro cytopathic effect inhibition assay with the H3N2 influenza virus A/Hong Kong/68 (HK/68), the bark extract of Burkea africana was found to be a promising antiviral lead with an IC50 value of 5.5 μg/mL without noteworthy cytotoxicity in Madin Darby canine kidney cells. After several chromatographic steps, triterpene saponins of the lupane and oleanane types were identified as the bioactive principles. In total, eight new triterpene saponins (1-8) with four so far undescribed aglycone structures were isolated and characterized via HRESIMS, GC-MS, and 1D and 2D NMR spectroscopy...
February 2, 2018: Journal of Natural Products
https://www.readbyqxmd.com/read/29394050/ent-jungermannenone-c-triggers-reactive-oxygen-species-dependent-cell-differentiation-in-leukemia-cells
#20
Zongwei Yue, Xinhua Xiao, Jinbao Wu, Xiaozhou Zhou, Weilong Liu, Yaxi Liu, Houhua Li, Guoqiang Chen, Yingli Wu, Xiaoguang Lei
Acute myeloid leukemia (AML) is a hematologic malignancy that is characterized by clonal proliferation of myeloid blasts. Despite the progress that has been made in the treatment of various malignant hematopoietic diseases, the effective treatment of AML remains very challenging. Differentiation therapy has emerged as a promising approach for leukemia treatment, and new and effective chemical agents to trigger the differentiation of AML cells, especially drug-resistant cells, are urgently required. Herein, the natural product jungermannenone C, a tetracyclic diterpenoid isolated from liverworts, is reported to induce cell differentiation in AML cells...
February 2, 2018: Journal of Natural Products
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