Three New Cytochalasins from the Marine‐Derived Fungus Spicaria elegans KLA03 by Supplementing the Cultures with L ‐ and D ‐Tryptophan

Three new cytochalasins Z(21) -Z(23) (1-3, resp.), together with five analogs, 4-8, were isolated from Spicaria elegans KLA03 by the OSMAC (one strain-many compounds) approach with adding L- and D-tryptophan during its cultivation. The structures of new cytochalasins were elucidated on the basis of comprehensive 1D- and 2D-NMR and HR-ESI-MS analyses. Cytochalasins Z(21) and Z(22) (1 and 2, resp.), and compound 5 showed cytotoxic activities against A-549 cell lines with IC(50) values of 8.2, 20.0, and 3.1 μM, respectively.