BASTADIN-20 AND BASTADIN O-SULFATE ESTERS FROM IANTHELLA-BASTA - NOVEL MODULATORS OF THE RY(1)R FKBP12 RECEPTOR COMPLEX

New compounds bastadin 20 (9), 15,34-O-disulfatobastadin 7 (10), and 1 0-O-sulfatobastadin 3 (11) were isolated from Ianthella basta collecte d in Exmouth Gulf, Western Australia. Compounds 10 and 11 exhibited mo derate differential activity as SR Ca2+ channel agonists (EC(50) 13.6 and 100 mu M, respectively) of the Ry(1)R FKBP12 complex, while the po tency of 9 was almost half that of 10 (EC(50) 20.6 mu M). The problem of dereplication of bastadins was addressed using H-1-NMR ''fingerprin ting'' of MeO signals in the corresponding permethyl bastadin derivati ves.