Cytotoxic Ergosteroids from a Strain of the Fungus Talaromyces adpressus

Nine new ergosteroids ( 1 – 9 ) and seven known ones ( 10 – 16 ) were isolated from Talaromyces adpressus . Their structures and absolute configurations were determined by the interpretation of NMR spectroscopic data, HRESIMS, ECD calculations, and single-crystal X-ray diffraction analyses. Structurally, compound 1 was an ergosteroid with two epoxy and a 3 α -OH group at ring A, while compounds 8 and 9 had a contracted ring A with a peroxy bridge between C-3 and C-9, which were reported for the first time. Compounds 2 – 6, 9, 11, and 15 displayed cytotoxic activities with IC 50 values ranging from 0.4 to 32 μ M, and compound 7 exhibited an immunosuppressive effect against LPS-induced B lymphocyte proliferation with an IC 50 value of 8.6 μ M. The structure–activity relationships of these compounds are briefly discussed.