Aspochalasin D is a potent inhibitor of mammalian tumor cell lines, first isolated from Aspergillus microcysticus by Keller-Schierlein and co-worker in 1979. While known to be an epimer of aspochalasin C, the stereochemistry was not resolved until Hayakawa and co-workers at University of Tokyo re-isolated the metabolite as a selective apoptosis inducer in Ras-dependent pathways in 2001.