| The contents of this dissertation describe the chemical investigations of various Indo-Pacific marine sponges with the hope of finding novel compounds that possess compelling cytotoxicity. The first study included the examination of multiple Psammocinia spp. in an effort to find more psymberin, a compound that was undergoing further biological evaluation at the Josephine Ford Cancer Center (JFCC) and National Cancer Institute. The second study involved investigation of the marine sponge, Hyrtios sp. which resulted in the isolation of two new compounds, and the third sponge investigation of a Jaspis splendens resulted in the isolation of one new compound.;The first chapter introduces marine natural products chemistry, and how to successfully isolate and identify new compounds. The chapter discusses challenges faced during the following studies, and how they were overcome. This chapter ends with concluding remarks on future approaches to studying marine natural products. The chapters following the introduction discuss the results from the above mentioned studies. The contents of chapter two explore and develop a biogeographical study of the marine sponge Psammocinia which led to the successful isolation of more psymberin. During this study, a new compound named psymbamide A (2) was isolated. The second chapter discusses elucidation of compound 2, results from the biological assessment of 1, and the structure activity relationship of psymberin to date.;The third chapter discloses two new compounds from a Hyrtios sp., 15-oxo-puupehenoic acid (3) and 20-epi-hydroxyhaterumadienone (4), collected in Papua New Guinea. Puupehenones are a class of compounds that possess a wide range of bioactivities which are outlined in chapter 3, including the assessment of 3 and 4 in a human lipoxygenase assay. Chapter four has both significant structure and biological contributions to the cytotoxic compound class of jasplakinolides. A new compound, jasplakinolide R (5), introduces the first marine sponge derived quinazoline-containing compound and we report the first example of a jasplakinolide analog (jasplakinolide B (6)) possessing potent nM cytotoxicity without microfilament reorganization. |
