Macrocyclic Trichothecene Mycotoxins from a Deadly Poisonous Mushroom, Podostroma cornu-damae

Three new macrocyclic trichothecenes(1–3) and five known related compounds (4–8) were isolated from the MeOH extract of a plate culture of the fungus Podostroma cornu-damae, a deadly poisonous mushroom. Miophytocen D (1) is a rearranged macrocyclic type D trichothecene, featuring a bicyclo-[6.5]dodecahydrocyclopenta[b]chromene scaffold, and the structures of new compounds (1–3) were delineated by the combination of 1D and 2D NMR spectroscopic experiments and HRESIMS, modified Mosher’s esterification, and quantum chemical ECD calculations. The isolated compounds (1–8) were evaluated for cytotoxicity against four human breast cancer cell lines (Bt549, HCC70, MDA-MB-231, and MDA-MB-468). Compounds 4, 6, and 8 exhibited significant cytotoxic effects against the breast cancer cell lines, with IC50 values in the range of 0.02–80 nM, which is stronger than doxorubicin, the positive control, and a structure–activity relationship was suggested.