Sesquiterpenoids from the Mangrove-Derived Endophytic Fungus <i>Diaporthe</i> sp.

A new sesquiterpenoid, diaporol A (<b>1</b>), possessing a unique tricyclic lactone framework, eight new drimane sesquiterpenoids, diaporols B–I (<b>2</b>–<b>9</b>), and the known compounds <b>10</b> and <b>11</b> were isolated from a culture of the mangrove-derived endophyte <i>Diaporthe</i> sp. The absolute configurations of <b>1</b>–<b>5</b> were determined by low-temperature (100 K) single-crystal X-ray diffraction with Cu Kα radiation. The compounds were evaluated for cytotoxic activity; however, no compound showed significant cytotoxicity against the tested cell lines at a concentration of 20 μM