New Bioactive Polyketides from the Mangrove-Derived Fungus Penicillium sp. SCSIO 41411

Three new polyketides, including three ester derivatives (<b>1</b>, <b>3</b>, and <b>5</b>) and a new natural product, which was a benzoquinone derivative, embelin A (<b>4</b>), together with nine known ones (<b>2</b> and <b>6</b>-<b>13</b>), were isolated from the mangrove-derived fungus <i>Penicillium</i> sp. SCSIO 41411. Their structures were determined by detailed NMR and MS spectroscopic analyses. The X-ray single-crystal diffraction analysis of <b>4</b> was described for the first time. Compound <b>9</b> displayed obvious inhibition against PDE4 with an inhibitory ratio of 40.78% at 10 μM. Compound <b>12</b> showed DPPH radical scavenging activity, with an EC₅₀ of 16.21 µg/mL, compared to the positive control (ascorbic acid, EC₅₀, 11.22 µg/mL). Furthermore, compound <b>4</b> exhibited cytotoxicity against PC-3 and LNCaP with IC₅₀ values of 18.69 and 31.62 µM, respectively.