F-12509A, a new sphingosine kinase inhibitor, produced by a discomycete

In the course of our screening for inhibitors of sphingosine kinase, we fou nd an active compound from a culture broth of a discomycete, Trichopezizell a barbata SANK 25395. The structure of the compound, named F-12509A, was el ucidated by a combination of spectroscopic analyses, to be a new sesquiterp ene quinone consisting of a drimane moiety and a dihydroxybenzoquinone. Enz yme kinetic analyses showed that F-12509A inhibits sphingosine kinase activ ity in a competitive manner with respect to sphingosine, with a K-i value o f 18 mu M.