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Title:Structure Elucidation and Biosynthesis of Selected Bioactive Marine Natural Products (Bromophenols, Aplysina, Fistularis, Kelletia)
Author(s):Tymiak, Adrienne Anne
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Organic
Abstract:The biosynthesis of bromophenols in Aplysina fistularis has been reinvestigated, making use of liposome-encapsulated precursors. The incorporation of both phenylalanine and tyrosine into two antimicrobial sponge metabolites, 2,6-dibromo-4-hydroxy-2,5-cyclohexadienone-4-acetamide and 4,6-dibromohomogentisamide, was demonstrated for the first time. Also, {('15)N,('14)C}phenylalanine was shown to be a precursor of the former metabolite, thus providing evidence for the intermediacy of oximes in the conversion of amino acids to other sponge metabolites of biological interest. A biosynthetic pathway consistent with these experiments has been proposed.
Anomalous "Aplysina spongelii" sponge samples have been studied. Bioactive components of one specimen (later reclassified as Smenospongia aurea) were isolated and identified as 5-bromo- and 5,6-dibromo-N,N-dimethyltryptamines and a sesquiterpenoid hydroquinone, aureol. In addition, spectroscopic evidence for two new aplysinopsin derivatives, 6-bromo-aplysinopsin and 6-bromo-4'-N-de-methylaplysinopsin was obtained. Different arrays of these five metabolites were found during a chemotaxonomic survey of morphologically similar Caribbean sponges.
Kelletinins I and II, {erythrityl tetrakis(p-hydroxybenzoate) and 2-deoxy-D-ribityl tetrakis (p-hydroxybenzoate)}, two novel and antibacterial metabolites of the marine mollusk Kelletia kelletii, have been isolated and their structures have been elucidated. Assignments of the structures were based on high-field NMR and mass spectrometric data and were confirmed by spectral comparisons of derivatized natural products and synthetic compounds. Other bioactive metabolites have been found to be structurally related, but less polar, less bioactive and less abundant, analogs of the kelletinins. Kelletinins I and II provide a new class of antimicrobial marine natural products and are among the very few antimicrobial compounds isolated from hard-shelled mollusks.
Issue Date:1983
Description:134 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
Other Identifier(s):(UMI)AAI8310020
Date Available in IDEALS:2014-12-15
Date Deposited:1983

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