91桃色

Abstract

Fungi are among the most important groups of eukaryotic organisms that have played a pivotal role as sources for drug leads during the last century. Different environmental factors may change the behavior of the fungi and favor the production of diverse range of secondary metabolites. Accordingly, this study involved alternative biochemical studies of some unexplored ecological niches. The first part of the study described the chemical investigation of the fungus Alternaria sp. an endophytic fungus isolated from the seeds of the traditional medicinal plant Ziziphus jujube. Twenty one metabolites have been obtained from Alternaria sp. Five of them are isocoumarin derivatives that were obtained for the first time from this genus. The remaining sixteen compounds isolated from the same fungus included alternariol derivatives and the new; 7-methoxyphathalide-3-acetic acid. The alternariol derivatives and some of the structurally related compounds showed high cytotoxic activity when tested against L5178Y mouse lymphoma cell line as well as pronounced antibacterial activities. The second part of the study was devoted to halophilic fungi as sources of bioactive metabolites. As an example Penicillium sp. isolated from the sediments of a hyper-saline lake of Wadi El-Natrun, Egypt. Eight compounds were isolated from such fungus including two new epidithiodiketopiperazine analogues named, pretichodermamide C and N-methylpretichodermamide B. The last compound proved to be highly active against the L5178Y cancer cell line. These results support the notion of an ecology based-approach to selection of fungal species for chemical studies, as this approach can be effective in the discovery of new bioactive fungal metabolites.

Biography

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