Current Search: Hall, Andrew (x)
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Title
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Natural Product Studies of Marine Organisms from the Western Atlantic.
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Creator
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Hall, Andrew, West, Lyndon, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Chemistry and Biochemistry
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Abstract/Description
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The projects described in this dissertation are focused on compounds derived from marine organisms collected from the western Atlantic marine environment. Chapter 1 provides an introduction to the study of natural products chemistry, marine natural products, and overview of the research undertaken from natural product chemists. Chapter 2 describes the isolation and structure elucidation of a series of rare diterpenoids from the gorgonian Briareum asbestinum, together with their conformational...
Show moreThe projects described in this dissertation are focused on compounds derived from marine organisms collected from the western Atlantic marine environment. Chapter 1 provides an introduction to the study of natural products chemistry, marine natural products, and overview of the research undertaken from natural product chemists. Chapter 2 describes the isolation and structure elucidation of a series of rare diterpenoids from the gorgonian Briareum asbestinum, together with their conformational analysis and biosynthetic interconversions. These rare diterpenes from Briareum asbestinum are linked by an unusual transannular oxa-6π electrocyclization which is described in detail and this work demonstates the biomimetic hemisynthesis of briareolate esters L (19) to B (22) achieved via an intermediary, briareolate ester G (2), through a controlled set of photoinduced isomerizations and a unique photochromic transannular oxa-6π electrocyclization. This work focuses largely on the mechanistic understanding of the photochemical production of these briarane diterpenoids and illustrates a unique UVA/UVC, photochromic switch which induces a transannular oxa- 6π electrocyclization. Chapter 3 describes the assay-guided isolation of marine antioxidants. This chapter focuses on the screening of marine organism extracts using the Ferric Reducing Antioxidant Power (FRAP) assay for antioxidant activity guided isolation of marine natural products. The chapter concludes with the activity guided isolation and structural elucidation of 1-O-palmitoyl-2-O-myristoyl-3-O-(6-sulfo-α-D-quinovopyranosyl)- glycerol (40) to show direct antioxidant potential through FRAP analysis. Chapter 4 describes the isolation, structural elucidation and pharmacological evaluation of the novel secondary metabolites iso-PsA(45), Iso-PsC (46), iso-PsD (47) as well as known Pseudopterosins A(41), B(42), C(43), D(44), K(48), K2’OAc(49), K2’OAc(50). These secondary metabolites were evaluated for both cytotoxicity. The chapter concludes with the screening of these compounds as αβ-amyloid fibril modulators utilizing atomic force microcopy (AFM).
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Date Issued
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2016
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PURL
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http://purl.flvc.org/fau/fd/FA00004666
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Subject Headings
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Marine natural products., Diterpenes., Marine metabolites
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Format
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Document (PDF)
