Bioactive compounds from marine sponges

Several marine sponges from Okinawan waters have been examined for bioactive compounds. Further investigation with Polyfibrospongia sp. which have already yielded novel metabolites gave new hennoxazoles (6-9), of which 7 was moderately cytotoxic. Echinocluthn'a sp. furnished new pyridine alkaloids (1 0-1 2), two of which showed immunosuppressive activity. A sponge identified to be Dysidea herbacea afforded cytotoxic 20,24-dimethyldeoxoscalarin-3-one 4) along with known diterpenes. Two cytotoxic dimers (15,16) of a sesquiterpene have been isolated from Halichondria sp. Mytiloxanthin derivatives (1 8,19) were the major pigments of Phakellia stellidem. A new species of the family Niphatidae gave highly cytotoxic polyacetylenes (2 0-2 6).