Gliocladium roseum KF-1040, a marine isolate, was found to produce a series of new inhibitors of diacylglycerol acyltransferase (DGAT). Four active compounds, designated roselipins 1A, 1B, 2A and 2B, were isolated from the fermentation broth of the producing strain by solvent extraction, ODS column chromatography and preparative HPLC. The highest production of roselipins tvas observed when cultured in the medium containing natural sea water. Roselipins inhibit DGAT activity with IC50 values of 15 similar to 22 mu M a in an enzyme assay system using rat liver microsomes.