New metabolites from sponge-derived fungi Curvularia lunata and Cladosporium herbarum

The fungus Curvularia lunata, isolated from the marine sponge Niphates olemda, yielded the new 1,3,8-trihydroxy-6-methoxyanthraquinone, which we named lunatin (1), the known modified bisanthraquinone cytoskyrin A (2), and the known plant hormone (+)-abscisic acid (3). Both anthraquinones were found to be active against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli. Two strains of the fungus Cladosporium herbarum, isolated from the sponges Aplysina aerophoba and Callyspongia aerizusa, respectively, yielded two new alpha-pyrones, herbarin A (4) and herbarin B (5), the, known compound citreoviridin A (6), and the new phthalide herbaric acid (7). All structures were unambiguously established by 1D and 2D NMR and MS data.