Structure elucidation of a novel cyclic tripeptide from the marine-derived fungus DSW-2.

A novel cyclic tripeptide, sclerotiotide M (), was isolated from the culture of a marine derived fungus DSW-2, together with four known compounds (-). The planar structure of was established by 1 D and 2 D NMR data, supported by mass spectrometry, and the relative configuration was established by calculated NMR chemical shifts coupled with a statistical method (DP4+). All the compounds (-) displayed weak cytotoxic activities against cancer cell lines HPAC and BXPC3, with IC values over 20 μM.