| Marine organisms represent a rich source of bioactive secondary metabolites. These bioactive compounds are often present in trace quantities in the organism and their clinical development has been hampered by lack of an available supply. The supply problem can be addressed by a chemical synthesis or through biological methods such as aquaculture, cell culture or enzymatic means. The overall goal of this research was to conduct biosynthetic studies of the marine alkaloids ET 743 and stevensine, and the diterpenes fuscol and fuscoside A-D. The motivation for this is that biosynthetic data could be used to develop a biotechnological production method.; ET 743, an anti-cancer agent, is the main alkaloid produced by Ecteinascidia turbinata. Since DKP of DOPA is a key intermediate in ET 743 biosynthesis and since the chemical synthesis of DOPA derivatives is problematic, we developed an enzymatic production method using tyrosine hydroxylase as a tool to oxidize DKP of tyrosine to DKP of DOPA.; Stevensine and oroidin are bromopyrrole alkaloids isolated from the marine sponge Axinella corrugate. Stevensine exhibits antimicrobial activity as well as cytotoxicity in vitro against murine leukemia cells. We were able to develop an enzyme based method to identify the amino acids precursors for Stevensine and oroidin using a cell-free extract of the sponge.; Fuscosides are diterpene arabinose glycosides isolated from the Caribbean soft coral Eunicea fusca. They and the aglycone fuscol are potent anti-inflammatory compounds with long-lasting effect and have a selective inhibitory action against leukotriene production in murine models of inflammation. We identified and confirmed the intermediary of the diterpenes cyclase product using radioactivity-guided isolation. Furthermore, we completed the elucidation of fuscol biosynthetic pathway. We provided evidence for the use of these diterpenes as oxygen scavengers in the organism. In addition, we investigated the biosynthetic source of the diterpenes in E. fusca and we provided direct evidence for their production by the microbes (bacteria or fungi) present in the organism. |
