A NEW EGF-ACTIVE POLYMERIC PYRIDINIUM ALKALOID FROM THE SPONGE CALLYSPONGIA-FIBROSA

An inhibitor of the epidermal growth factor (EGF) receptor was isolated from an extract of the Micronesian sponge Callyspongia fibrosa. The structure of the EGF-active compound was first proposed, on the basis of ion-spray mass spectrometry, to be the cyclic dimer 1 (n = 2) but comparison of a sample produced by an efficient synthetic route revealed that hypothesis to be incorrect. The EGF-active constituent must therefore be a large oligomer or a polymer of the same repeating subunit 1.