Doctor of Philosophy (Ph.D.)
Degree Granting Department
Bill J. Baker, Ph.D.
Valerie J. Harwood, Ph.D.
James W. Leahy, Ph.D.
Edward Turos, Ph.D.
Alcyonacean, Epigenetic modifications, Marine Natural Products, Metabolomics, Penicillium
Considered the pulse controlling the biological interactions and contributing to the ecological survival of organisms, natural products have intrigued, challenged, and stimulated the scientific and non-scientific minds for millennia. Drug resistance and the lack of suitable potent drugs against neglected tropical diseases further motivate the biological activity assessment of these secondary metabolites, when possible.
This thesis describes the chemical investigation of two marine organisms and the elucidation of eight novel structures.
The study of a deep sea Antarctic coral unveils six novel terpenoid structures from three different molecular classes: sesquiterpenoid alcyopterosins, a triterpene steroid, and three prostaglandins. While mass availability made it possible for the steroid and the prostaglandins to be tested for biological activity against the Leishmania donovani and the Plasmodium falciparum parasites, the potency of the novel alcyopterosin compounds could not be evaluated. However, a structure-activity relationship study comparing two of the known isolated alcyopterosin isolated along the process of investigation was feasible and contributed to the extension of the biological activity knowledge of these molecules.
The epigenetically modified culture of a tropical mangrove fungal endophyte yielded a potent antileishmanial novel sesterterpene. The originality and exclusivity of the molecular framework offered by this compound drove the research exploration to find conditions enhancing the compound production. The investigation methodology incorporated hyphenated liquid chromatography-mass spectrometry methods to evaluate the most favorable culture conditions and optimize the chemical isolation and purification of the compound of interest through dereplication methods. Despite some inconclusive results, serendipity on the research path led to the isolation of another novel sesterterpene.
Natural products research entails the alliance of various fields including organic, physical, and analytical chemistry with biology, ecology and medicine. This thesis illustrates these collaborations through the chemical investigation of marine organisms for the purpose of drug discovery.
Scholar Commons Citation
Limon, Anne-Claire D., "Antarctic Deep Sea Coral and Tropical Fungal Endophyte: Novel Chemistry for Drug Discovery" (2019). USF Tampa Graduate Theses and Dissertations.