Sesterterpene γ-hydroxybutenolide with a unique carbon skeleton isolated from the marine sponge Dysidea etheria de Laubenfels. First naturally occurring inhibitor of the protein phosphatase, cdc25; the inhibition of which blocks cell division. Isolation, activity and crystal structure: S. P. Gunasekera et al., J. Am. Chem. Soc. 118, 8759 (1996). Enantioselective synthesis: E. J. Corey, B. E. Roberts, ibid. 119, 12425 (1997). Total synthesis of racemate and preliminary biological activity: S. R. Magnuson et al., ibid. 120, 1615 (1998).