Cyclopentenone and wickerol derivatives from the marine algicolous fungus A-YMD-9-4.

A new cyclopentenone derivative, 4-hydroxyhypocrenone A, and a new naturally-occurring wickerol derivative, 8-acetoxywickerol A, as well as two known compounds, hypocrenone A and wickerol B, were purified from A-YMD-9-4, an endophytic fungus isolated from the marine red alga . The structures and relative configurations of two new isolates were established by a combination of 1 D/2D NMR, IR, and mass spectroscopic methods, and the absolute configuration of was assigned on the basis of ECD data analyzed by quantum chemical calculations. Compounds and exhibited weak inhibition of one or two marine phytoplankton species.