Sulphated furanosesterterpenes from two sponges of the genus Ircinia

Together with the previously described (18R)-variabilin (1a), its 13Z-isomer 2a, ircinin 1 (3a) and ircinin 2 (4a), the corresponding sulfates 1b-4b were isolated from sponges of the genus Ircinia, collected in the Northern Adriatic Sea. The structural elucidation and biological activity of these compounds are reported.