Cyclic Peptides from the Soft Coral-Derived Fungus Aspergillus sclerotiorum SCSIO 41031.

Three novel cyclic hexapeptides, sclerotides C-E ( 1 - 3 ), and a new lipodepsipeptide, scopularide I ( 4 ), together with a known cyclic hexapeptide sclerotide A ( 5 ), were isolated from fermented rice cultures of a soft coral-derived fungus: Aspergillus sclerotiorum SCSIO 41031. The structures of the new peptides were determined by 1D and 2D NMR spectroscopic analysis, Marfey's method, ESIMS/MS analysis, and single crystal X-ray diffraction analysis. Scopularide I ( 4 ) exhibited acetylcholinesterase inhibitory activity with an IC 50 value of 15.6 μM, and weak cytotoxicity against the human nasopharyngeal carcinoma cell line HONE-EBV with IC 50 value of 10.1 μM.