Bastadin 20 and Bastadin O-Sulfate Esters from Ianthella basta: Novel Modulators of the Ry1R FKBP12 Receptor Complex

Abstract
New compounds bastadin 20 (9), 15,34-O-disulfatobastadin 7 (10), and 10-O-sulfatobastadin 3 (11) were isolated from Ianthella basta collected in Exmouth Gulf, Western Australia. Compounds 10 and 11 exhibited moderate differential activity as SR Ca2+ channel agonists (EC50 13.6 and 100 μM, respectively) of the Ry1R FKBP12 complex, while the potency of 9 was almost half that of 10 (EC50 20.6 μM). The problem of dereplication of bastadins was addressed using 1H-NMR “fingerprinting” of MeO signals in the corresponding permethyl bastadin derivatives.