Sesquiterpene Quinones from a Marine Sponge Hippospongia sp. that Inhibit Maturation of Starfish Oocytes and Induce Cell Cycle Arrest with HepG2 Cells

Bioassay-guided isolation of the marine sponge Hippospongia sp. collected at Palau led to the isolation of three sesquiterpene quinone metabolites. They were determined as ilimaquinone (1), 5-epi.-ilimaquinone (2), and 5-epi.-isospongiaquinone (3) by NMR data analysis. Compounds 2 and 3 were obtained as a mixture (ca. 4:1). The cytotoxicity on human tumor cell lines of NCI-H460, HepG2, SF-268, MCF-7, HeLa, and HL-60, inhibitory effects on starfish oocytes maturation, and cell cycle arrest on HepG2 cell line for all compounds were evaluated.