New secondary metabolites from the marine endophytic fungus Apiospora montagnei.

The marine fungus Apiospora montagnei was isolated from the inner tissue of the North Sea alga Polysiphonia violacea. Cultivation of this fungal strain led to the isolation of several new secondary metabolites, including the diterpene myrocin A (1) and the polyketide apiosporic acid (2). Furthermore the new monomethyl ester of 9-hydroxyhexylitaconic acid (3) and the (-)-enantiomer (4) of the known (+)-hexylitaconic acid were found together with the known (+)-epiepoxydon (5), (+)-epoxydon monoacetate, R-mellein, R-8-methoxymellein, 5-hydroxymethylfuran-2-carboxylic acid, and the xanthone derivative anomalin A. The structures were elucidated mainly by 1D and 2D NMR, MS, UV, and IR spectral data. Compound 5 exhibited significant cytoxicity against human cancer cell lines.