Discovery of natural products from marine derived fungi and endophytic fungi
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Date
2023-10
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University of New Brunswick
Abstract
Natural products are an abundant source of bioactive, complex, and diverse chemical structures. This thesis describes the isolation and structure elucidation of natural products biosynthesized by marine-derived fungi and endophytic fungi with the primary objective of the research being the discovery of new chemical structures. The thesis is divided into two parts: the discovery of new natural products and the development of a new dereplication platform. Three fungal isolates were investigated to discover new natural products. First, investigation of a Penicillium sp. fungus isolated from sea foam resulted in the discovery of a new phenalenone derivative that selectively inhibits the growth of Staphylococcus aureus and Mycobacterium tuberculosis. Second, investigation of an Aureobasidium pullulans fungus isolated from needles of Thuja occidentalis (white cedar), led to the isolation of two new C11-polyketides that inhibit the growth of Mycobacterium tuberculosis. Finally, investigation of a Tolypocladium sp. fungus isolated from the marine macroalga Spongomorpha arcta led to the isolation of two new lipopeptaibols that inhibit the growth of Gram-positive bacteria and mycobacteria. Although these five natural products are new, they are structural derivatives of previously discovered molecules rather than being structurally novel. To improve the likelihood of discovering novel natural products in the future, Structural similarity Network Annotation Platform for Mass Spectrometry (SNAP-MS) was developed. SNAP-MS utilizes molecular networking topology and structural similarity fingerprinting to generate annotations of natural product compound families to aid in the dereplication process. This platform addresses limitations of many currently existing tools, such as the lack of publicly available reference data for most natural products and provides a new tool for analyzing complex mass spectrometry experiments that will improve dereplication capabilities and improve the likelihood of discovering novel natural products.