Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 38 for “"bioassay guided fractionation"”.
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Bioassay-guided fractionation of Artemisia afra for in vitro antimalarial activity against Plasmodium falciparum
With the increase in recent years in the prevalence of malaria, and in drug resistance of Plasmodium falciparum, there has been much interest in natural plant products for new antimalarials with novel modes of action against Plasmodium. Artemisinin or Qinghaosu is one such antimalarial isolated …
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Studies of Bioactive Natural Products and Mechanism-Based Bioassays
… in the A2780 ovarian cancer cell line assay. Bioassay-guided fractionation of an extract of a sponge of species <i>Dysidea</i> using the A2780 bioassay yielded the known scalarane sesterterpenoid heteronemin in good yield. Four derivatives of heteronemin were prepared semisynthetically from …
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The Isolation of Natural Products From Plant Extracts
Bioassay-guided fractionation of the ethyl acetate extract of Virola sp. (Myristicaceae) using the Sc7 yeast strain resulted in the isolation of the weakly cytotoxic biochanin A (an isoflavone compound). The bioassay of three mutant yeast strains (1138, 1104, and 1353) directed the isolation of …
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Antiplasmodial neolignans from Trema orientalis : identification, synthesis and analogue generation.
… as the major active compounds using two bioassay-guided fractionation approaches. The new accelerated “HPLC biogram” methodology allowed for early recognition of the active compounds in the complex plant extract, requiring considerably less time and material compared to the classical …
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Isolation and Synthesis of Bioactive Compounds from Plants
… anti-inflammatory activity (PPAR-y inhibition). Bioassay-guided fractionation of extracts led to the identification of four new antiproliferative compounds (2.1-2.3, 3.1), five new anti-inflammatory compounds (6.4a, 6.5a-b, 6.6a, 6.6c), and twenty-eight known compounds from eight of the extracts. …
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Discovery, Isolation, and Identification of Antimalarials from Fungal Endophytes
… the active constituent(s) of our extracts. Bioassay-guided fractionation techniques were used to isolate our active compound, the structure of which was elucidated using <super>1</super>H- and <super>13</super>C-NMR. 2D-NMR and LC-MS analyses helped confirm that our endophytes were indeed …
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Phytochemical studies on traditional medicinal plants with antimalarial activities
… (V elloziaceae) were investigated by employing bioassay guided fractionation. Two novel compounds and five known constituents were isolated from the active fractions of these three plants. The types of compounds isolated included: three triterpenoids (20(29)-Lupene-3α,28- diol (30), …
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Isolation, Structure Elucidation, and Total Synthesis of Biologically Active Natural Products from Plants
… the shikimate pathway in Plasmodium falciparum. Bioassay-guided fractionation of the extracts led to the identification of nineteen compounds with both antiplasmodial and antiproliferative activity, and thirteen compounds with only antiproliferative activity. Thirteen of these compounds (2.1 – …
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Isolation And Characterization Of Natural Antimicrobials From Plant And Marine Organisms
… against a number of high priority pathogens. Bioassay-guided fractionation of four extracts led to the identification of compounds with inhibitory activity; including one previously unknown compound. Compounds were evaluated through a variety of techniques including broth microdilution assay …
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Isolation, Structure Elucidation, and Synthesis of Natural Products from Marine Cyanobacteria
… a cyanobacterium collected in Panama underwent bioassay-guided fractionation and yielded the novel compound naranjamide, which showed activity against <em>P. falciparum</em> the protozoa responsible for malaria. Syntheses of naranjamide and its nonmethylated analog were attempted in order to …
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Isolation and Structure Elucidation of Antiproliferative Agents From Madagascar Rainforests
… cell line and hence were selected for further fractionation. Six compounds were isolated from these extracts. The structure elucidation and characterization of these compounds was carried out using mass spectrometry and 1D and 2D NMR techniques. The bioassay-guided fractionation of Roupellina …
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Antiproliferative Natural Products from the Madagascar Rainforest
… based on their antiproliferative activity. Bioassay-guided fractionation of five of the extracts yielded sixteen new compounds, and their structures were determined using a combination of 1D and 2D NMR experiments, including COSY, HSQC/HMQC, HMBC, and ROESY/NOESY sequences, mass …
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Isolation and Structure Elucidation of Anticancer and Antimalarial Natural Products
… antiproliferative and antimalarial activities. Bioassay guided fractionation of thirteen extracts led to the identification of three new antiproliferative compounds, ethyl leptaulosides A-C (5.1-5.3), six new antiplasmodial compounds, apoplanesiacarpan A and B (2.4-2.5), (±)-rhodomyrtosone F …
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Isolation and Structure Elucidation of Antiproliferative and Antiplasmodial Natural Products from Plants
… antiplasmodial activities. With the guidance of bioassay guided fractionation, two known antiproliferative terpenoids (2.1 and 2.2) were isolated from Hypoestes sp. (Acanthaceae), four known antiplasmodial liminoids (3.1-3.4) were isolated from Carapa guianensis (Meliaceae), one inactive …
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Antileishmania Compounds From An Unidentified Endophytic Fungus And Biotransformation Of 5,7,2`,4`,5`-Pentahydroxyflavonol
… the activity and structure are correlated. The bioassay-guided fractionation of Limonium myrianthum resulted in the isolation of 5,7,2',4',5'- pentahydroxyflavonol. This compound possessed significant antifungal activity against the fungal pathogens Candida glabrata and Candida krusei at IC50 …
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Pharmacognostic study of 5 medicinal plant species from Western Cape Province (South Africa) for anti-tubercular activity
… infectious diseases such as tuberculosis. A bioassay guided fractionation of the acetone/water (4:1) crude extracts of O. capensis (leaves) and T. alliacea (rhizomes) showed no activity against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 252923, and Mycobacterium aurum A+. In …
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Isolation and Structure Elucidation of Anticancer and Antimalarial Natural Products
… against the Dd2 strain of Plasmodium falciparum. Bioassay-guided fractionation of seven of the extracts yielded twenty new compounds and twenty-four known compounds, and their structures were elucidated by using a combination of 1D (1H and 13C) and 2D NMR spectroscopy including COSY, HASQC, HMQC, …
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Development and Application of a Novel Assay for Rapid Identification of Cellular Prion Protein Modulators
… with potential PrPC-suppressing activity. Bioassay-guided fractionation and chemical profiling enabled the characterization of natural hits, further expanding the potential therapeutic candidates. Further applications of LIPS in CRISPR-based genetic screenings revealed novel molecular …
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Hormetic dietary phytochemicals from Western Canadian plants: Identification, characterization and mechanistic insights
… extracts capable of doubling the activity of QR. Bioassay-guided fractionation of six extracts led to the identification of novel classes of compounds with QR-inducing activity including fatty-acid derived polyacetylenes, phthalides, and cannabinoids. Studies using low molecular weight thiols and …
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Fungi-derived natural products with binding affinities for human opioid or cannabinoid receptors
… fungi species were selected and subjected to bioassay-guided fractionation affording a total of twenty-nine compounds which were identified using standard spectrometric and spectroscopic methods. Two new benzyl derivatives (1 and 2) and seven known compounds (3-9) were isolated and identified …
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