Cytotoxic meroterpenoids from the marine sponge <i>Dactylospongia elegans</i>

Abstract

Three new sesquiterpene quinones/hydroquinones, 20-demethoxy-20-isopentylaminodactyloquinone D (<b>1</b>), 20-demethoxy-20-isobutylaminodactyloquinone D (<b>2</b>), and 19-methoxy-dictyoceratin-A (<b>3</b>), and five known related compounds (<b>4</b>-<b>8</b>) were isolated from the marine sponge <i>Dactylospongia elegans</i>. Their structures were elucidated by spectroscopic analysis, ECD calculation, single-crystal X-ray diffraction, and comparison with the literature. Compounds <b>3</b> and <b>5</b>-<b>8</b> exhibited activities against the human cancer cell lines DU145, SW1990, Huh7, and PANC-1 with IC₅₀ values ranging from 2.33 to 37.85 μM.