Callyspongamide A, a new cytotoxic polyacetylenic amide from the Red Sea sponge Callyspongia fistularis.

Callyspongamide A (1), a new cytotoxic polyacetylenic amide, has been isolated from the marine sponge Callyspongia fistularis collected in the Red Sea. Callyspongamide A is an amide derivative of a C(17)-polyacetylenic acid and phenethylamine. It represents a new class of secondary metabolites within the family Callyspongiidae. Its structure was determined on the basis of 1D and 2D (COSY, HOHAHA, HMQC, and HMBC) NMR studies and high-resolution mass spectral measurement.