New antifungal tetrahydrofuran derivatives from a marine sponge-associated fungus Aspergillus sp. LS78

Abstract

Two new tetrahydrofuran derivatives named aspericacids A and B (1 and 2) were isolated from the metabolites produced by the sponge-associated Aspergillus sp. LS78. They represented an unusual type of tetrahydrofuran derivatives, possessing 2,5-disubstituted tetrahydrofuran ring coupled with a chain unsaturated fatty acid. The planar structures of 1 and 2 were determined by HRESIMS, 1D and 2D NMR spectroscopy. The absolute configuration of 1 was assigned using both experimental and computational electronic circular dichroism (ECD). In addition, aspericacid A (1) exhibited in vitro antifungal activity (MIC = 50 μg/mL), but 2 showed not significantly activity against any of the tested strains with the MIC values of 128 μg/mL.

Keywords: Antifungal; Aspergillus; Aspericacid; Sponge-associated; Tetrahydrofuran derivatives.