Diterpene metabolites from two chemotypes of the marine sponge Myrmekioderma styx.

Three apparent chemotypes of the marine sponge Myrmekioderma styx exist. An acyclic diterpene, styxenol A [1], has been isolated from the shallow water chemotype, while three tricarbocyclic diterpenes 3, 6, and 7 have been isolated from the deep chemotype. The structures were elucidated based on spectral methods including homo- and hetero-nuclear 2D nmr experiments. Compounds 1, 3, and 6 exhibit moderate cytotoxicity against the P-388 murine leukemia cell line and the A549 human lung tumor cell line.