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Franklin Turner

Posted on April 5, 2017


Date - April 5, 2017
1:00 pm


MS Thesis – 602
Title: “Isolation of Fungal Secondary Metabolites: Leporin B, Benzoisoquinoline and Related Compounds.”


Natural products have proven to be a good source of anticancer drugs since the 1940’s. In fact, they have influenced the creation of 65% of all 246 anticancer drugs since that time. Fungi in particular provide an almost untapped source of compounds with promising bioactivity. To access compounds from natural products, an extraction and purification process using flash chromatography, and high performance liquid chromatography is needed. Characterization of those compounds is done using high-resolution mass spectrometry and NMR spectroscopy. These methods were used to isolate and characterize six known compounds that were added to an in-house database. Leporin B, leporin C, austdiol and 7-epi-austdiol were all isolated from Scytalidium cuboideum strain 68345. Leporin B has specifically proven to be effective in different aspects of research including, its effect on hexokinase II and it has shown potential as a cytotoxic compound towards cancer cells.  The re-isolation of leporin B has increased the in-house supply for use in future experimentation. Through the re-isolation of leporin B, leporin C was found. Leporin C is new to natural product; however, the compound has been previously synthesized, and it only differs from the structure of leporin B by one oxygen atom. Austdiol and 7-epi-austdiol were also isolated during the search for leporin B. Fungal strain MSX74367 was also studied, and yielded, 9-O-methylbostrycoidin and 8-O-methylfusarubin. The benzoisoquinoline structure, the core structure of 9-O-methylbostrycoidin and 8-O-methylfusarubin, is new to the current in-house database of over 300 compounds isolated from fungi. Mass defect analysis and high-resolution mass spectrometry were used in an effort to isolate other benzoisoquinoline type compounds through mass guided fractionation; however, the process was unsuccessful in finding additional analogues. In total, six compounds were found from two different strains of fungi, all of which were new to an in-house database. The fungusScytalidum cuboideum, in particular, produced leporin B and leporin C, which was isolated for the first time from a natural source.