Secondary metabolites from sponges (phylum Porifera)

Secondary metabolites of Tasmanian sponges (phylum Porifera) have been studied. This study involved bioassay, separation (mainly using chromatography), and structural determination (mainly using spectroscopy). Eleven terpenoids and one nucleoside, all of which have been structurally identified by spectroscopy, have been isolated from six sponges. Two new furanoditerpenes (26) and (28) which are related to ambliofuran have been isolated from Cacospongia sp. (sponge 89048). The known dendrolasin (66) and a new sesquiterpene (75) which are also analogous to ambliofuran have been isolated from sponge 89060. Sponge 88043 (Ircinia sp.1) gave a novel C\(_{21}\) furanoterpene (51). Compound (51) represents the first C\(_{21}\) furanoterpene having a 10 membered ring which has been obtained from a marine organism. The known C31 terpenoid quinol (52) and C\(_{31}\) terpenoid quinone (53) have been isolated from Ircinia sp.2 (sponge 90032). Variabilin (55) which was very toxic against brine shrimp and the new C\(_{24}\) chlorinated furanoterpene (54) were also isolated from sponge 90032. The known 2'-deoxyuridine (63) from Tedania sp.1 (sponge 88047) has a similar structure to spongouridine. This is the first time that this nucleoside has been isolated from a sponge. The known sesterterpenes (64) and furospinosulin-1 (65) were isolated from Tedania sp.2 (sponge 88049). Biogenetic considerations ("isoprene rule") of the terpenoids under study are discussed; they are generally constructed by the conventional head-to-tail linkage of isoprenoid units. The sponges which have been investigated were selected based on results of preliminary studies using dc and brine shrimp assays