New dihydrobenzofuranoid from the marine-derived fungus Aspergillus ustus KMM 4664.

One new dihydrobenzofuran derivative (1), known depsipeptide emericellamide A (2), three known drimanes (3–5) and two artifact drimane derivatives (6, 7) were isolated from the marine-derived fungus Aspergillus ustus KMM 4664. Their structures were determined by detailed analysis of spectroscopic data and by comparison with related known compounds. The absolute configuration of 1 was determined by time-dependent density functional theory (TD-DFT) calculations of ECD spectra. Compound 7 showed significant ability of the inhibition of spermatozoa to fertilize egg-cells of the sea urchin Strongylocentrotus intermedius with IC₅₀ value 21 µM. [ABSTRACT FROM AUTHOR]