LC-MS/MS-based discovery of new cytochalasin from fungus <i>Rosellinia sanctae-cruciana</i>

The ethyl acetate extract of the fungus Rosellinia sanctae-cruciana was analysed using LC-MS/MS, revealing a peak at m/z 558.272 [M + H]+ with the molecular formula C30H39NO9, indicative of the cytochalasin class. The isolated compound, 18 Da higher in molecular weight than 19,20-Epoxycytochalasin-N, featured an opened diol structure at positions 5 and 6. Named Cytochalasin-Augusta, it was purified using HPLC and characterised by 1H NMR,13C NMR, HSQC, HMBC, and NOESY spectroscopy.