| Fungi are chemically rich sources of secondary metabolites which possess interesting biological activities. Many important antibiotics have been isolated from terrestrial fungi including the penicillins and the cyclosporins which have dramatically improved treatments for infectious diseases. Recently, the investigation of marine fungi as a source of new bioactive compounds has contributed significantly to natural products chemistry, and the secondary metabolites reported in literature were reviewed in this study.; Due to the increasing rate of mycoses among humans, animals and plants, the search for new antifungal drugs has become an important and challenging area in natural products drug discovery. The goal of this thesis research was to develop an antifungal assay that can be used for screening a large number of chemical extracts and for determination of the antifungal activity of the compounds of interest. This was accomplished by modifying a colorimetric microdilution broth assay, generally recommended for susceptibility testing of antifungal drugs, for the purpose of screening.; The second aim of the thesis, the chemical investigation of marine fungi which exhibited antifungal activity in the screening program, led to the isolation of new sesterterpenes, which are a rare group of terpenoids. These compounds showed a broad range of biological activities including antifungal, antibacterial and cytotoxicity. This work illustrated the potential of marine fungi as a unique source for novel natural products. |
