Sesquiterpene Quinones/Hydroquinones from the Marine Sponge <i>Spongia pertusa</i> Esper

Nine new sesquiterpene quinones/hydroquinones (<b>1</b>–<b>7</b>, <b>10</b>, and <b>12</b>), three solvent-generated artifacts (<b>8</b>, <b>9</b>, and <b>11</b>), and three known compounds, 5-<i>epi</i>-smenospongine (<b>13</b>), smenospongine (<b>14</b>), and smenospongiadine (<b>15</b>), were isolated from the marine sponge <i>Spongia pertusa</i> Esper. The planar structures of the new compounds were elucidated on the basis of spectroscopic analyses. Their absolute configurations were determined by comparison between the calculated and experimental ECD spectra. In the cytotoxicity bioassay, compounds <b>13</b>–<b>15</b> exhibited activities against the human cancer cell lines U937, HeLa, and HepG2, with most potent cytotoxicities to U937 cells with IC₅₀ values of 2.8, 1.5, and 0.6 μM, respectively. In addition, compound <b>6</b> displayed CDK-2 affinity with a <i>K</i>_d value of 4.8 μM in a surface plasmon resonance assay