Bolinaquinone: A novel cytotoxic sesquiterpene hydroxyquinone from a Philippine Dysidea sponge

Abstract

Sesquiterpene hydroxyquinones and hydroquinones have been isolated from various sponges.3-16 The sesquiterpene moiety of these metabolites usually have the normal drimane skeleton, as exemplified by spongiaquinone (1),3 a rearranged drimane skeleton, as in ilimaquinone (2)4 and isospongiaquinone (3),3.5 or a monocyclic sesquiterpenoid skeleton, as in metachromin C (4)6 (Chart 1). Recently, Patil and co-workers isolated related sesquiterpene derivatives, frondosins A−E, which feature a 6,7-bicyclic skeleton, as exemplified by frondosin A (5).7 We report here the isolation and structure determination of a cytotoxic sesquiterpene hydroxyquinone, bolinaquinone (6), which showed a rearranged drimane skeleton but with a different position for the hydroxyquinone moiety.