Global ETD Search
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Showing 1 to 20 of 37 for “"diterpene"”.
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Structure and function of class I diterpene synthase
… has served as a model for investigation of diterpene synthase activity, and here we report its crystal structure at 2.3 Å resolution. This bifunctional enzyme catalyzes both class I (ionization-initiated), as well as class II (protonation initiated) cyclization reactions, and is composed of …
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Structure and Biosynthesis of the Diterpene Hydrocarbon, Casbene
The stereochemical course of the enzyme catalyzed cyclization of geranylgeranyl pyrophosphate (GGOPP) to casbene, (1S,14R)-(E,E,E)-3,7,11,15,15-pentamethylbicyclo{14.1.0}pentadeca-2,6,10-triene, was defined in the castor bean plant (Ricinus communis L.,) by resolving the four stereochemical …
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Application of ketenes and allenes in the total synthesis of diterpene quinones and indoles
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1995.
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Investigating the evolution of cytochromes P450 involved in GA biosynthesis
<p>Vascular plants invariably contain a class II diterpene cyclase (EC 5.5.1.x), as an ent-copalyl diphosphate synthase is required for gibberellin phytohormone biosynthesis. This has provided the basis for evolution of a functionally diverse enzymatic family. A bifunctional diterpene synthase was …
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Molecular and Functional Characterization of Terpene Chemical Defense in Arabidopsis Roots in Interaction with the Herbivore Bradysia spp. (fungus gnat)
… the constitutive formation of the novel volatile diterpene compound, rhizathalene, in Arabidopsis roots. Rhizathalene synthase is a class I diterpene synthase that has high affinity for the substrate geranylgeranyl diphosphate (GGPP) and is targeted to the root leucoplast. Expression of the …
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Extractable organics and colour in a bleached kraft mill effluent land application system and recipient ground waters
… were resin acids, largely saturated species, and diterpene hydrocarbon transformation products. Diterpene hydrocarbons were dominated by retene, fichtelite, and dehydroabietin. Surficial sediments contained concentrations of total resin acids and diterpene hydrocarbons of up to 10,000 mg kg⁻¹. …
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Studies directed toward the total synthesis of salvilenone
… total synthesis of salvilenone, a phenalenone diterpene found in the roots of Salvia miltiorrhiza Bunge, are reported via a double annulation strategy. The key steps in the proposed synthesis involve a regiocontrolled benzannulation involving the photochemical Wolff rearrangement of an a-diazo …
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Diterpenes as models for the study of their effect on neural progenitor cells and on cytochrome p-450 enzymes
… as a source of secondary metabolites, mainly diterpenes. Exhaustive studies of the spectroscopic and spectrometric data were explored following two basic axes: 1- Phytochemical investigation : Phytochemical investigation on latex of Euphorbia resinifera led to the ísolation and identification …
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Design Synthesis and Evaluation Of Diterpenones As Potent Chemopreventive Agents For Aflatoxin B1 Induced Carcinogenesis In Human Liver Cells
… of terpene QM precursors, a homoconjugated diterpene catechol was synthesized. A review of the literature revealed that Cu2+ -induced oxidation of simple catechols proceeds through a two-step one electron transfer process, and o-quinone is the sole oxidation product. In contrast, our studies …
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Extraction and Characterization of Xylopic Acid from Xylopia aethiopica
… to the presence of Xylopic acid the major diterpene component of the fruit oil extract. This work examines the effects of extraction solvent and time of extraction on the yield of xylopic acid. Xylopic acid was isolated from the dried fruits of<em> Xylopia aethiopica</em> using petroleum …
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Synthetic studies towards total synthesis of bielschowskysin
… product bielschowskysin. Bielschowskysin, a new diterpene isolated from the Caribbean gorgonian octocoral Pseudopterogorgia kallos, possesses a fascinating tricyclic [5-4-9] ring architecture, unprecedented in the realms of natural products. This diterpene exhibits antiplasmodial activity against …
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Synthesis Of A Novel Family Of Amide Derivatives Of Podocarpic Acid
… this work, podocarpic acid, a natural tricyclic diterpene, derived from Podocarpus species, has been employed to form a novel family of amide derivatives which will later be studied for their potential as new drug leads. Novel amide derivatives of podocarpic acid were synthesized from podocarpic …
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Enhanced yield of medicinal products from Tripterygium cell cultures
… large amounts of pharmacologically active diterpene and triterpene natural products. A method was developed where elicitation with a strain of the fungus Botrytis stimulated the production of oleanane and friedelane triterpene acids. In rapidly growing twelve liter bioreactor cultures, …
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PROTEOMICS INSIGHTS INTO MOLECULAR MECHANISMS OF TRIPTOLIDE AGAINST COLORECTAL CANCER
Triptolide, a diterpene triepoxide extracted from traditional Chinese medicinal plant, Leigongteng, has been shown to have strong anti-tumor activities. However, the molecular mechanisms of triptolide against colorectal cancer remains largely elusive to date. In my study, triptolide was …
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Isolation, Characterization, and Synthesis of Bioactive Natural Products from Rainforest Flora
… and analysis with standards by GCMS. Two new diterpenes were isolated from Hymenaea courbaril, which in an earlier investigation provided a new diterpene. The absolute configurations of these diterpenes were assigned on the basis of anisotropic NMR studies, X-ray crystallography, circular …
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Liganden des Benzodiazepin-Rezeptors: Studien über Benzodiazepine in pflanzlichen Geweben sowie über Hispidulin
… fünf aktive Komponenten, drei Flavone und zwei Diterpene, isoliert. Die BZD-R-aktiven Flavone wurden als Apigenin (5,7,4’-Trihydroxyflavon), Hispidulin (5,7,4’-Trihydroxy-6-methoxyflavon)und Cirsimaritin (5,4’-Dihydroxy-6,7-dimethoxyflavon identifiziert. Bei den diterpenoiden BZD-R-Liganden …
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Part I : Isolation Of Dipentyl 2-(4-(pentan-3-yl) Phenyl) Malonate From Sanguisorba Officinalis Labill Part II: Synthesis Of A Novel Family Of Ethers Of Podocarpic Acid
… using podocarpic acid (a natural tricyclic diterpene derived from podocarpus species) as a template. Novel ether derivatives of podocarpic acid were synthesized from podocarpic acid in three steps. The first step involved methylation of podocarpic acid with dimethyl sulfate to form …
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Antiproliferative activities of Euphorbia bicolor (euphorbiaceae) and Maclura pomifera (moraceae) extracts on estrogen receptor-positive and triple-negative breast cancer cell lines
… AKT and pAKT protein levels. Euphorbia bicolor diterpene extracts demonstrated antiproliferative effects in estrogen receptor-positive T47D and triple-negative MDA-MB-231 breast cancer cells. In MDA-MB-231 cells, apoptosis was induced through TRPV1-mediated calcium overload, similarly to M. …
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Phytochemische und pharmakologisch-biologische Untersuchungen von Arnica montana und Vernonia triflosculosa
… erstmals beschrieben wurden. Diterpene wurden hier zum ersten Mal in der Gattung Vernonia nachgewiesen. Zwei Hirsutinolide zeigten eine starke hemmende Aktivität die NF-kapha-B-DNA-Bindung und auf die IL-8-Produktion.
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Testing the Anti-Inflammatory Effects of Dietary Phytochemicals in Intestinal Inflammation Models
… culinary and medicinal herb abundant in diterpenes, understudied antioxidant and anti-inflammatory phytochemicals. Carnosic acid (CA) and carnosol (CL) are the most abundant diterpenes in rosemary, however less abundant diterpenes are understudied. Fractions that excluded CA and CL from …
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