(-)-Frondosins A and D, HIV-Inhibitory Sesquiterpene Hydroquinone Derivatives fromEuryspongiasp

(-)-Frondosins A and D, two sesquiterpene hydroquinone metabolites, were isolated and identified from the HIV-inhibitory organic extracts of the marine sponge Euryspongia sp. In contrast to the decalin rings found previously in bicyclic marine sesquiterpene quinones and quinols, (-)-frondosins A and D possess the less common bicyclo[5.4.0]undecane sesquiterpene ring system.