A New Cyclic Hexapeptide and a New Isocoumarin Derivative from the Marine Sponge-Associated Fungus Aspergillus similanensis KUFA 0013

摘要

A new isocoumarin derivative, similanpyrone C (>1), a new cyclohexapeptide, similanamide (>2), and a new pyripyropene derivative, named pyripyropene T (>3) were isolated from the ethyl acetate extract of the culture of the marine sponge-associated fungus Aspergillus similanensis KUFA 0013. The structures of the compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compound >2 the stereochemistry of its amino acid constituents was determined by chiral HPLC analysis of the hydrolysate by co-injection with the d and l amino acids standards. Compounds >2 and >3 were evaluated for their in vitro growth inhibitory activity against MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A373 (melanoma) cell lines, as well as antibacterial activity against reference strains and the environmental multidrug-resistant isolates (MRS and VRE). Only compound >2 exhibited weak activity against the three cancer cell lines, and neither of them showed antibacterial activity.