Cytotoxic and Antibacterial Preussomerins from the Mangrove Endophytic Fungus <i>Lasiodiplodia theobromae</i> ZJ-HQ1

Two new chlorinated preussomerins, chloropreussomerins A and B (<b>1</b> and <b>2</b>), together with nine known preussomerin analogues, <b>3</b>–<b>11</b>, were obtained from the endophytic fungus <i>Lasiodiplodia theobromae</i> ZJ-HQ1. Their structures were elucidated by a combination of spectroscopic analyses. The absolute configurations of <b>1</b> and <b>2</b> were both determined by single-crystal X-ray diffraction using Cu Kα radiation. Chloropreussomerins A and B (<b>1</b> and <b>2</b>) are the first chlorinated compounds in the preussomerin family, and preussomerin M (<b>3</b>) is reported for the first time as a natural product. Compounds <b>1</b> and <b>2</b> showed potent <i>in vitro</i> cytotoxicity against A549 and MCF-7 human cancer cell lines, with IC<sub>50</sub> values ranging from 5.9 to 8.9 μM, and compounds <b>4</b>–<b>7</b> exhibited significant bioactivity against A549, HepG2, and MCF-7 human cancer cell lines, with IC<sub>50</sub> values of 2.5–9.4 μM. In the antibacterial assay, compounds <b>1</b>, <b>2</b>, <b>5</b>–<b>7</b>, and <b>11</b> exhibited significant activities against <i>Staphylococcus aureus</i>, with MIC values between 1.6 and 13 μg/mL.