Illudalane sesquiterpenoids from the soft coral Alcyonium paessleri: The first natural nitrate esters

Fifteen illudalane sesquiterpenoids, alcyopterosins A-O (1-15) have been is olated from the subAntarctic soft coral Alcyonium paessleri which was colle cted at a depth of 200 m near the South Georgia Islands, and their structur es were elucidated by spectroscopic techniques. Eight of these compounds (2 , 3, 5-8, 10, and 13) are the first natural nitrate esters, while the other four (1, 4, 11, and 12) are chlorinated. These compounds are as well the f irst illudalane sesquiterpenoids to be isolated from the marine environment . Compounds 1, 3, 5, and 8 showed mild cytotoxicity toward human tumor cell lines.