Two new benzophenones and one new natural amide alkaloid isolated from a mangrove-derived Fungus <i>Penicillium citrinum</i>

<p>Two new compounds penibenzophenones A-B (<b>1–2</b>), and the synthetic <i>α</i>,<i>β</i>-unsaturated amide alkaloid (<i>E</i>)-tert-butyl(3-cinnamamidopropyl)carbamate (<b>4</b>), newly identified as a natural product, alone with three known ones (<b>3</b>, <b>5–6</b>) were isolated from the EtOAc extract of the endophytic fungus <i>Penicillium citrinum</i> HL-5126 isolated from the mangrove <i>Bruguiera sexangula var. rhynchopetala</i> collected in the South China Sea. Compound <b>1</b> was a chlorinated benzophenone. The structures of <b>1–6</b> were elucidated by extensive NMR spectral interpretation, MS data and X-ray analysis. The new compound <b>2</b> displayed cytotoxic activity against human A549 cell lines with an IC<sub>50</sub> value of 15.7 μg/mL, and <b>1</b> showed antibacterial activity against <i>Staphylococcus aureus</i> with a MIC value of 20 μg/mL.</p>