Contignasterines,Anti-Inflammatory 2‑AminoimidazoleSteroids from the Sponge <i>Neopetrosia</i> cf. <i>rava</i> Collected in the Bismarck Sea

Sponges of the genus <i>Neopetrosia</i> are known for the production of a large diversity of bioactive metabolites. Contignasterines A (<b>1</b>) and B (<b>2</b>) were isolated as major metabolites of the sponge <i>Neopetrosia</i> cf. <i>rava</i> collected in the Bismarck Sea along with the known and highly bioactive steroid contignasterol (<b>3</b>) possessing a similar oxidized aglycone. Contignasterines are characterized by the presence of a 2-aminoimidazole branched on the side-chains of the oxidized steroid, and <b>1</b> also contains an unusual phosphate group at C-7. The anti-inflammatory activities of these compounds were investigated and revealed that all three compounds inhibited the production of pro-inflammatory mediators.