New metabolites from the sponge Spongia agaricina.

The sponge Spongia agaricina from Tarifa, Cadiz, Spain, contains two new 9,11-secosterols, [3-0-deacetylluffasterol B (1) and 3-0-deacetyl-22,23-dihydro-24,28-dehydroluffasterol B (2)] and two new sesterterpenoids [12,16-di-epi-12-0-deacetyl-16-0-acetylfuroscalarol (3) and 16-epi-scalarolbutenolide (4)], in addition to the known compounds 5-15. The structures of all compounds were elucidated by interpretation of' spectroscopic data. The metabolites 1-3 showed significant cytotoxicity against four tumor cell lines (C50 1 microgram/mL).