Dokument: New Natural Products from Endophytic Fungi-Structure Elucidation and Biological Activity
| Titel: | New Natural Products from Endophytic Fungi-Structure Elucidation and Biological Activity | |||||||
| Weiterer Titel: | Neue Naturstoffe aus endophytischen Pilzen-Strukturaufklärung und biologisches Screening | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=21561 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20120605-090035-7 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Deutsch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Ebrahim, Weaam Nabil El Sayed [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Proksch Peter [Gutachter] Prof. Dr. Kassack, Matthias U. [Gutachter] | |||||||
| Dewey Dezimal-Klassifikation: | 600 Technik, Medizin, angewandte Wissenschaften » 610 Medizin und Gesundheit | |||||||
| Beschreibung: | Plant endophytic fungi produce natural products with a large diversity of
chemical structures which might prove to be suitable for specific medicinal or agrochemical applications. Most of these secondary metabolites show biological activities in pharmaceutically relevant bioassay systems and thus represent potential lead structures which could be optimized to yield effective therapeutic and bioactive agents. The aim of this work was the isolation of secondary metabolites from endophytic fungi, followed by structure elucidation and examination of their pharmocological potential. Four endophytic fungal strains (Corynespora cassiicola, Stemphylium botryosum, Stemphylium solani and Embellisia eureka) were selected as biological sources. The fungi were grown in liquid Wickerham medium as well as in solid rice medium for a period of three to four weeks. The extracts obtained were then subjected to different chromatographic separation techniques in order to isolate the secondary metabolites. Structure elucidation of secondary metabolites was performed using state- of-the-art analytical techniques, including mass spectrometry (MS) and nuclear magnetic resonance (NMR) experiments. In addition, in the case of selected optically active natural products, chiral derivatisation methods were applied in order to determine their absolute configuration. Finally, the isolated compounds were subjected to various bioassays to examine their cytotoxic activities. 1. Corynespora cassiicola Corynespora cassiicola was isolated from the Mangrove plant Laguncularia racemosa (Combretaceae). Eighteen compounds were isolated from different cultures of Corynespora cassiicola. These compounds belong to naphthaquinones, octalactones, decalactones and depsidones. Fourteen compounds are new natural products. Conclusion 256 2. Stemphylium botryosum Eight compounds were isolated from solid rice cultures of Stemphylium botryosum. These compounds represent mainly pyrones. Two compounds are new natural products. 3. Stemphylium solani Two compounds were isolated from solid rice cultures of Stemphylium solani. One compound of these isolated compounds is a new natural product. 4. Embellisia eureka Thirteen compounds were isolated from solid rice cultures of Embellisia eureka. These compounds include phthalides, isocoumarines and pyrrocidines. Ten compounds are new natural products. The two pyrrocidines derivatives show potent cytotoxic activity against L5178Y, A2780sens., A2780CisR. and many other cell lines. A total of forty-one compounds were isolated in this study, twenty seven of which were identified as new natural products. Both known and new compounds were tested for their biological activities using different bioassay systems. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 05.06.2012 | |||||||
| Dateien geändert am: | 05.06.2012 | |||||||
| Promotionsantrag am: | 29.11.2008 | |||||||
| Datum der Promotion: | 01.06.2012 |
