Spicochalasin A and New Aspochalasins from the Marine‐Derived Fungus <i>Spicaria elegans</i>

Abstract

Abstract Different culture conditions directed by the OSMAC (one strain‐many compounds) approach drastically modified the metabolites of the fungus Spicaria elegans , which yielded the novel spicochalasin A ( 1 ), five new aspochalasins M–Q ( 2 – 6 ), and two known aspochalasins ( 7 and 8 ). The gross structures of 1 – 6 were elucidated by 1D and 2D NMR and MS methods, and their absolute configurations were determined by X‐ray diffraction and the Mosher ester method. Spicochalasin A ( 1 ) has a unique pentacyclic system and was found to be moderately cytotoxic towards human leukemic HL‐60 cells with an IC 50 value of 19.9 μ M .(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)