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Phytochemistry

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https://www.readbyqxmd.com/read/28088302/the-cyp79a1-catalyzed-conversion-of-tyrosine-to-e-p-hydroxyphenylacetaldoxime-unravelled-using-an-improved-method-for-homology-modeling
#1
Dario Vazquez-Albacete, Marco Montefiori, Stefan Kol, Mohammed Saddik Motawia, Birger Lindberg Møller, Lars Olsen, Morten H H Nørholm
The vast diversity and membrane-bound nature of plant P450s makes it challenging to study the structural characteristics of this class of enzymes especially with respect to accurate intermolecular enzyme-substrate interactions. To address this problem we here apply a modified hybrid structure strategy for homology modeling of plant P450s. This allows for structural elucidation based on conserved motifs in the protein sequence and secondary structure predictions. We modeled the well-studied Sorghum bicolor cytochrome P450 CYP79A1 catalyzing the first step in the biosynthesis of the cyanogenic glucoside dhurrin...
January 11, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28065397/sensory-active-piperine-analogues-from-macropiper-excelsum-and-their-effects-on-intestinal-nutrient-uptake-in-caco-2%C3%A2-cells
#2
Katja Obst, Barbara Lieder, Katharina V Reichelt, Michael Backes, Susanne Paetz, Katrin Geißler, Gerhard Krammer, Veronika Somoza, Jakob P Ley, Karl-Heinz Engel
The phytochemical profile of Macropiper excelsum (G.Forst.) Miq. subsp. excelsum (Piperaceae), a shrub which is widespread in New Zealand, was investigated by LC-MS-guided isolation and characterization via HR-ESI-TOF-MS and NMR spectroscopy. The isolated compounds were sensorily evaluated to identify their contribution to the overall taste of the crude extract with sweet, bitter, herbal and trigeminal impressions. Besides the known non-volatile Macropiper compounds, the lignans (+)-diayangambin and (+)-excelsin, four further excelsin isomers, (+)-diasesartemin, (+)-sesartemin, (+)-episesartemin A and B were newly characterized...
January 5, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28062072/two-rare-antioxidant-and-anti-inflammatory-oleanenes-from-loop-root-asiatic-mangrove-rhizophora-mucronata
#3
Kajal Chakraborty, Vamshi Krishna Raola
Two oleanenes, olean-18(19)-en-3β-yl-(3,6-dimethyl-3E,6Z-dienoate) and (13α)-27-frido-olean-14(15)-en-(17α)-furanyl-3β-ol representing a class of rare natural pentacyclic triterpenoids were isolated from the chloroform extract of Asiatic mangrove, Rhizophora mucronata Lam. (Family: Rhizophoraceae). The furanyl oleanene exhibited significantly greater antioxidative activities (IC50 0.73-0.76 mg/mL), than prenylated oleanene (IC50 0.84-0.96 mg/mL) (P < 0.05). No significant differences in anti-5-lipoxygenase activities of these compounds with the synthetic drug ibuprofen was discernable (IC50 0...
January 3, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28062071/chemical-profile-and-defensive-function-of-the-latex-of-euphorbia-peplus
#4
Juan Hua, Yan Liu, Chao-Jiang Xiao, Shu-Xi Jing, Shi-Hong Luo, Sheng-Hong Li
Plant latex is an endogenous fluid secreted from highly specialized laticifer cells and has been suggested to act as a plant defense system. The chemical profile of the latex of Euphorbia peplus was investigated. A total of 13 terpenoids including two previously unknown diterpenoids, (2S*,3S*,4R*,5R*,6R*,8R*,l1R*,13S*,14S*,15R*, 16R*)-5,8,15-triacetoxy-3-benzoyloxy-11,16-dihydroxy-9-oxopepluane and (2R*,3R*, 4S*,5R*,7S*,8S*,9S*,l3S*,14S*,15R*)-2,5,8,9,14-pentaacetoxy-3-benzoyloxy-15-hydroxy-7-isobutyroyloxyjatropha-6(17),11E-diene), ten known diterpenoids, and a known acyclic triterpene alcohol peplusol, were identified, using HPLC and UPLC-MS/MS analyses and through comparison with the authentic compounds isolated from the whole plant...
January 3, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28057327/occurrence-of-brassinosteroids-in-non-flowering-land-plants-liverwort-moss-lycophyte-and-fern
#5
Takao Yokota, Toshiyuki Ohnishi, Kyomi Shibata, Masashi Asahina, Takahito Nomura, Tomomichi Fujita, Kimitsune Ishizaki, Takayuki Kohchi
Endogenous brassinosteroids (BRs) in non-flowering land plants were analyzed. BRs were found in a liverwort (Marchantia polymorpha), a moss (Physcomitrella patens), lycophytes (Selaginella moellendorffii and S. uncinata) and 13 fern species. A biologically active BR, castasterone (CS), was identified in most of these non-flowering plants but another biologically active BR, brassinolide, was not. It may be distinctive that levels of CS in non-flowering plants were orders of magnitude lower than those in flowering plants...
January 2, 2017: Phytochemistry
https://www.readbyqxmd.com/read/28049552/antiproliferative-cyclodepsipeptides-from-the-marine-actinomycete-streptomyces-sp-p11-23b-downregulating-the-tumor-metabolic-enzymes-of-glycolysis-glutaminolysis-and-lipogenesis
#6
Xuewei Ye, Komal Anjum, Tengfei Song, Wenling Wang, Ying Liang, Mengxuan Chen, Haocai Huang, Xiao-Yuan Lian, Zhizhen Zhang
Two cyclodepsipeptides and a known cyclodepsipeptide valinomycin were isolated from a culture of the marine actinomycete Streptomyces sp. P11-23B. Their structures were established based on NMR, HRESIMS, and MS-MS spectroscopic interpretation as well as by chemical degradation. Both streptodepsipeptides P11A and P11B inhibited proliferation of different glioma cell lines, with IC50 values ranging from 0.1 μM to 1.4 μM. Streptodepsipeptide P11A was found to block the cell cycle at the G0/G1 phase and induce apoptosis in glioma cells...
December 31, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28043655/triterpene-saponins-from-the-roots-of-acacia-albida-del-mimosaceae
#7
Abdou Tchoukoua, Turibio Kuiate Tabopda, Shota Uesugi, Misa Ohno, Ken-Ichi Kimura, Eunsang Kwon, Hiroyuki Momma, Ibrahim Horo, Özgen Alankuş Çalişkan, Yoshihito Shiono, Bonaventure Tchaleu Ngadjui
Seven previously undescribed bidesmosidic triterpenoid saponins named albidosides A - G, were isolated from a methanol extract of the roots of Acacia albida. Their structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry and determined to be bidesmosides of oleanolic acid and of 16α-hydroxyoleanolic acid. Albidosides B - G were assayed for their cytotoxicity against HeLa and HL60 cells using MTT method and microscopic observation.
December 30, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28043654/selected-flavonoid-compounds-as-promising-inhibitors-of-protein-kinase-ck2%C3%AE-and-ck2%C3%AE-the-catalytic-subunits-of-ck2
#8
Andrea Baier, Anna Galicka, Jolanta Nazaruk, Ryszard Szyszka
CK2 is a ubiquitous protein kinase involved in many cell functions. During the last years it became an interesting target in cancer research. A series of flavonoid compounds was tested as inhibitors of protein kinase CK2. Several substances were found to be highly active against both catalytic subunits with IC50 values below 1 μM in case of CK2α'. The most promising inhibitor we identified is chrysoeriol with IC50 values of 250 and 34 nM for CK2α and CK2α', respectively.
December 30, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28038776/cloning-and-characterization-of-d-threonine-aldolase-from-the-green-alga-chlamydomonas-reinhardtii
#9
Yuki Hirato, Mayumi Tokuhisa, Minoru Tanigawa, Hiroyuki Ashida, Hiroyuki Tanaka, Katsushi Nishimura
d-Threonine aldolase (DTA) catalyzes the pyridoxal 5'-phosphate (PLP)-dependent interconversion of d-threonine and glycine plus acetaldehyde. The enzyme is a powerful tool for the stereospecific synthesis of various β-hydroxy amino acids in synthetic organic chemistry. In this study, DTA from the green alga Chlamydomonas reinhardtii was discovered and characterized, representing the first report to describe the existence of eukaryotic DTA. DTA was overexpressed in recombinant Escherichia coli BL21 (DE3) cells; the specific activity of the enzyme in the cell-free extract was 0...
December 27, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28034456/biotransformation-of-an-africanane-sesquiterpene-by-the-fungus-mucor-plumbeus
#10
Braulio M Fraga, Carmen E Díaz, Leonardo J Amador, Matías Reina, Matías López-Rodriguez, Azucena González-Coloma
Biotransformation of 8β-hydroxy-african-4(5)-en-3-one angelate by the fungus Mucor plumbeus afforded as main products 6α,8β-dihydroxy-african-4(5)-en-3-one 8β-angelate and 1α,8β-dihydroxy-african-4(5)-en-3-one 8β-angelate, which had been obtained, together with the substrate, from transformed root cultures of Bethencourtia hermosae. This fact shows that the enzyme system involved in these hydroxylations in both organisms, the fungus and the plant, acts with the same regio- and stereospecificity. In addition another twelve derivatives were isolated in the incubation of the substrate, which were identified as the (2'R,3'R)- and (2'S,3'S)-epoxy derivatives of the substrate and of the 6α- and 1α-hydroxy alcohols, the 8β-(2'R,3'R)- and 8β-(2'S,3'S)-epoxyangelate of 8β,15-dihydroxy-african-4(5)-en-3-one, the hydrolysis product of the substrate, and three isomers of 8β-hydroxy-african-4(5)-en-3-one 2ξ,3ξ-dihydroxy-2-methylbutanoate...
December 26, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28027775/triterpene-derivatives-from-euphorbia-enhance-resistance-against-verticillium-wilt-of-tomato
#11
Amal Smaili, Noureddine Mazoir, Lalla Aicha Rifai, Tayeb Koussa, Kacem Makroum, El Mostafa Kabil, Ahmed Benharref, Mohamed Faize
Oxidation of α-euphorbol and 31-norlanostenol, two triterpenic compounds isolated from the latex of Euphorbia resinifera and Euphorbia officinarum respectively, yielded four products named 3β-tosyloxy-4α,14α-dimethyl-5α-cholesta-7,9-diene; 4α,14α-dimethyl-5α-cholesta-7,9-dien-3β-ol; 24-methylen-elemo-lanosta-8,24-dien-3-one and elemo-lanost-8-en-3,11,24-trione. They were evaluated for protection of tomato plants against Verticillium dahliae in a greenhouse. The four semisynthesized products were phytotoxic at higher concentrations as they completely inhibited tomato germination at 100 and 500 μg/ml...
December 24, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28017365/acclimation-to-salt-modifies-the-activation-of-several-osmotic-stress-activated-lipid-signalling-pathways-in-chlamydomonas
#12
Harold J G Meijer, John A J van Himbergen, Alan Musgrave, Teun Munnik
Osmotic stress rapidly activates several phospholipid signalling pathways in the unicellular alga Chlamydomonas. In this report, we have studied the effects of salt-acclimation on growth and phospholipid signalling. Growing cells on media containing 100 mM NaCl increased their salt-tolerance but did not affect the overall phospholipid content, except that levels of phosphatidylinositol phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] were reduced by one-third. When these NaCl-acclimated cells were treated with increasing concentrations of salt, the same lipid signalling pathways as in non-acclimated cells were activated...
December 22, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28012567/%C3%AE-amyrin-synthase-esbas-and-%C3%AE-amyrin-28-oxidase-cyp716a244-in-oleanane-type-triterpene-saponin-biosynthesis-in-eleutherococcus-senticosus
#13
Hye-Jeong Jo, Jung Yeon Han, Hwan-Su Hwang, Yong Eui Choi
Siberian ginseng (Eleutherococcus senticosus) is a woody medical shrub belonging to the Araliaceae family. E. senticosus contains various types of saponins, including oleanane, noroleanane, lupane, and 3,4-secolupane types, depending on the aglycone structure. Oleanane-type triterpenes are the major saponin components in E. senticosus. Two enzymes (β-amyrin synthase and β-amyrin 28-oxidase) are essential for oleanane-type saponin biosynthesis from 2,3-oxidosqualene. In the present study, two full-length cDNAs encoding EsBAS and CYP716A244 were isolated based on transcriptomics analysis of plant leaves...
December 21, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28010885/gastroprotective-effects-of-hydroethanolic-root-extract-of-arrabidaea-brachypoda-evidences-of-cytoprotection-and-isolation-of-unusual-glycosylated-polyphenols
#14
Claudia Quintino da Rocha, Felipe Meira de-Faria, Laurence Marcourt, Samad Nejad Ebrahimi, Bruna Tiemi Kitano, Amanda Franceschini Ghilardi, Anderson Luiz Ferreira, Ana Cristina Alves de Almeida, Ricardo José Dunder, Alba Regina Monteiro Souza-Brito, Matthias Hamburger, Wagner Vilegas, Emerson Ferreira Queiroz, Jean-Luc Wolfender
The hydroethanolic root extract of Arrabidaea brachypoda, from Bignoniaceae family, a Brazilian medicinal plant, demonstrated significant in vivo gastroprotective effects using different in vivo assays. The activity was evaluated in several models of experimental gastric ulcer in rats (absolute ethanol, glutathione depletion, nitric oxide depletion, non-steroidal anti-inflammatory drugs, pylorus ligation and acetic acid). Using 300 mg/kg (p.o.) the extract significantly reduced gastric injury in all models...
December 20, 2016: Phytochemistry
https://www.readbyqxmd.com/read/28003047/bioactive-isopimarane-diterpenoids-from-the-stems-of-euonymus-oblongifolius
#15
Fei Li, Jie Ma, Chuang-Jun Li, Jing-Zhi Yang, Dan Zhang, Xiao-Guang Chen, Dong-Ming Zhang
Seven isopimarane diterpenes and one abietane diterpene, together with six known sesquiterpene derivatives, were isolated from the stems of Euonymus oblongifolius. Their structures were elucidated on the basis of spectroscopic analyses, and the absolute configuration of euonymusisopimaric acid A was confirmed by single-crystal X-ray crystallographic analysis using anomalous scattering of Cu Kα radiation. All of the isolated compounds were evaluated for their ability to inhibit LPS-induced nitric oxide production in the murine microglia BV2 cell line, and for their cytotoxic activity against five human cancer cell lines...
December 18, 2016: Phytochemistry
https://www.readbyqxmd.com/read/27998613/aba-and-ga3-regulate-the-synthesis-of-primary-and-secondary-metabolites-related-to-alleviation-from-biotic-and-abiotic-stresses-in-grapevine
#16
Germán Murcia, Ariel Fontana, Mariela Pontin, Rita Baraldi, Gianpaolo Bertazza, Patricia N Piccoli
Plants are able to synthesize a large number of organic compounds. Among them, primary metabolites are known to participate in plant growth and development, whereas secondary metabolites are mostly involved in defense and other facultative processes. In grapevine, one of the major fruit crops in the world, secondary metabolites, mainly polyphenols, are of great interest for the wine industry. Even though there is an extensive literature on the content and profile of those compounds in berries, scarce or no information is available regarding polyphenols in other organs...
December 17, 2016: Phytochemistry
https://www.readbyqxmd.com/read/27989370/antiplasmodial-dimeric-chalcone-derivatives-from-the-roots-of-uvaria-siamensis
#17
Abdul-Wahab Salae, Orapan Chairerk, Piyanut Sukkoet, Therdsak Chairat, Uma Prawat, Pittaya Tuntiwachwuttikul, Piya Chalermglin, Somsak Ruchirawat
Four dimeric chalcone derivatives, 8″,9″-dihydrowelwitschin H, uvarins A-C, a naphthalene derivative, 2-hydroxy-3-methoxy-6-(4'- hydroxyphenyl)naphthalene, and the known dimeric chalcones, dependensin and welwitschin E, flavonoids, a cyclohexane oxide derivative, an aromatic aldehyde were isolated from the roots of Uvaria siamensis (Annonaceae). The structures of the compounds were elucidated by spectroscopic analysis, as well as by comparison with literature data. The isolated compounds with a sufficient amount for biological assays were evaluated for their antimalarial, antimycobacterial, and cytotoxic activities...
December 15, 2016: Phytochemistry
https://www.readbyqxmd.com/read/27986278/preparation-characterization-and-biological-activity-of-c8-substituted-cytokinins
#18
Lenka Zahajská, Jaroslav Nisler, Jiří Voller, Tomáš Gucký, Tomáš Pospíšil, Lukáš Spíchal, Miroslav Strnad
Naturally occurring cytokinins are adenine-based plant hormones. Although, the effect of various substituents at positions N1, C2, N3, N(6), N7, or N9 on the biological activity of cytokinins has been studied, the C8-substituted compounds have received little attention. Here, we report the synthesis and in vitro biological testing of thirty-one cytokinin derivatives substituted at the C8 position of the adenine skeleton and twenty-seven compounds which served as their N9-tetrahydropyranyl protected precursors...
December 13, 2016: Phytochemistry
https://www.readbyqxmd.com/read/27979591/rebaudiosides-t-and-u-minor-c-19-xylopyranosyl-and-arabinopyranosyl-steviol-glycoside-derivatives-from-stevia-rebaudiana-bertoni-bertoni
#19
Wilmer H Perera, Ion Ghiviriga, Douglas L Rodenburg, Kamilla Alves, John J Bowling, Bharathi Avula, Ikhlas A Khan, James D McChesney
Two diterpene glycosides were isolated from a commercial Stevia rebaudiana leaf extract. One was found to be 13-[(2-O-β-d-glucopyranosyl-3-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid-(2-O-β-d-xylopyranosyl-3-O-β-d-glucopyranosyl- β-d-glucopyranosyl) ester (rebaudioside T), whereas the other was determined to be 13-[(2-O-β-d-glucopyranosyl-3-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]ent-kaur-16-en-19-oic acid-(6-O-α-l-arabinopyranosyl-β-d-glucopyranosyl) ester (rebaudioside U)...
December 12, 2016: Phytochemistry
https://www.readbyqxmd.com/read/27974159/phenolic-constituents-from-the-root-bark-of-morus-alba-l-and-their-cardioprotective-activity-in%C3%A2-vitro
#20
Xiao-Ke Zheng, Yan-Gang Cao, Ying-Ying Ke, Yan-Li Zhang, Fang Li, Jian-Hong Gong, Xuan Zhao, Hai-Xue Kuang, Wei-Sheng Feng
A flavanone C-glycoside, steppogenin-5'-C-β-D-glucopyranoside, six prenylated 2-arylbenzofuran derivatives, moracin O-3″-O-β-D-glucopyranoside, moracin O-3'-O-β-D-xylopyranoside, moracin P-2″-O-β-D-glucopyranoside, moracin P-3'-O-β-D-glucopyranoside, moracin P-3'-O-α-L-arabinopyranoside and moracin P-3'-O-[β-D-glucopyranosyl-(1 → 2)]-α-L-arabinopyranoside, two phenolic acids, 2,4-dihydroxy-5-(4-hydroxybenzyl) benzoic acid and 2,4-dihydroxy-5-(3,4-dihydroxybenzyl) benzoic acid, as well as three known compounds, moracinoside C, moracin O, and moracin P were isolated from the root bark of Morus alba L...
December 11, 2016: Phytochemistry
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