PTILOMYCALIN-A, CRAMBESCIDIN-800 AND RELATED NEW HIGHLY CYTOTOXIC GUANIDINE ALKALOIDS FROM THE STARFISHES FROMIA-MONILIS AND CELERINA-HEFFERNANI

Two novel pentacyclic guanidine alkaloids, celeromycalin 3 and fromiam ycalin 4, have been isolated from the New Caledonian starfishes Celeri na heffernani and Fromia monilis, respectively. Also found in Celerina heffernani are the known ptilomycalin A (1) and crambescidin 800 (2), which latter has been also isolated from Fromia monilis. The new comp ounds exhibited an high cytotoxic activity like the previous crambesci dins. These complex pentacyclic guanidines are typical sponges metabol ites and their occurence in starfishes is noteworthy. Fromia monilis a lso contained the less active component 5, made up from an hydroxysper midine residue linked to a long chain omega-hydroxyacid.