Extending the record of meroditerpenes from Cacospongia marine sponges.

A new meroditerpene, (+)-isojaspic acid (1), along with two known meroditerpenes, cacospongin D (2) and jaspaquinol (3), have been isolated from a marine sponge Cacospongia. Comprehensive taxonomic identification distinguished this Cacospongia apart from morphologically similar Psammocinia. The absolute stereochemistry of 1 was elucidated on the basis of extensive 1D and 2D NMR techniques and analysis of the optical rotation versus (+)-zonarol (8), (+)-isozonarol (9), (-)-dactylosponol (10), and (+)-hyatellaquinone (11). Furthermore, bioactivity evaluation showed that the meroditerpenes isolated significantly inhibited Staphylococcus epidermidis.