Marine microbes are regarded as one of the worthiest treasures for bioactive chemical Scaffolds. To search for anti-microbial secondary metabolites from marine environment, we isolated a marine-derived fungus Aspergillus terreus (MB14-HBr) from the sponge Haliclona species, Collected from Dongsha Atoll, Taiwan in May 2014. The isolated fungus was further cultured in laboratory and fungal metabolites were extracted by ethyl acetate (EtOAc). Preliminary anti-microbial assay indicated that EtOAc extract of MB14-HBr could inhibit the bacterial pathogen Acinetobacter baumannii and the fungal one Candida albicans, respectively. Besides interestingly, we also discovered that the crude EtOAc extract, fraction as well as pure compounds including dihydrogeodin (A-01), butryolactone II (A-02), Butryolactone I (A-06), Terrelumamide A (A-11) and Methyl 3,4,5-trimethoxy-2-(2-nicotinamido)benzamido)benzoate (A-15) exhibited siderophore-like (iron-chelating) effects in Chrome-azurol S (CAS) assay. Due to natural iron clutching properties of sidherophores, they have impending applications in cancer chemotherapy. Acinetobacter baumannii is an opportunistic human pathogen which is easy mutant to be several clinical antibiotics and very famous due to cause of nosocomial infection in human. Moreover, three compounds, butryolactone II (A-02), Butryolactone I (A-06) and methyl 3, 5 dichloro-asterric acid (A-03) showed activity in luciferase assay, suggested that these components might block Transforming Growth Factor (TGF)-β-induced transcriptional responses. The objective of this study is to isolate the bioactive components from the strain Aspergillus terreus. In order to isolate bioactive components, the EtOAc extract was subjected to Sephadex LH-20 column chromatography and reversed phase high performance liquid chromatography. As a result, a total of fifteen known compounds have been isolated from this fungal extract, including dihydrogeodin (A-01) butryolactoneII (A-02), methyl 3,5 dichloro-asterrric acid (A-03), 3R-methyl-6-hydroxy-8-methoxy isocoumarin (A-04), terretonin C (A-05), butryolactone I (A-06), geodin hydrate (A-07), 6,7-dimethoxy-4-hydroxymellein (A-08), butryolactone V (A-09), asterric acid (A-10), terrein (A-12) asterrelenin (A-13), terretonin (A-14) and methyl 3,4,5-trimethoxy-2-(2-nicotinamido)benzamido)benzoate (A-15). Moreover, we isolated one are peptide named terrelumamide-A (A-11). The structures of these isolates were elucidated on the basis of 1D and 2D NMR, Mass spectrometry, as well as literature data.
Key words: Aspegillus terreus, Anti-microbial activity, Acinetobacter baumannii, luciferase assay activity, MTS cell viability effect, Iron chelating effects.