NEW CYTOTOXIC STEROIDS FROM THE MARINE SPONGE DYSIDEA-FRAGILIS COMINGFROM THE LAGOON OF VENICE

The sterol composition of the sponge Dysidea fragilis, coming from the lagoon of venice, has been investigated; our results confirmed the va riability of D. fragilis biochemistry. The sponge elaborates, in addit ion to eight usual 3 beta-hydroxy sterols, thirteen polyhydroxysterols , eight of them (6-13) were novel compounds. Their structures weve est ablished by spectroscopic data. New compounds 3 beta,5 alpha,6 beta,7 alpha-tetrahydroxy-cholest-8(9)-en-11-one (8), 3 beta,5 alpha,6 alpha- trihydroxy-9,11-secocholest-7-en-9-one (9) and 3 beta,5 alpha,6 alpha, 9 alpha-tetrahydroxy-cholest-7-ene-6-sulfate (11) were proved to be cy totoxic on two different tumor cell lines in vitro.