One novel sesquiterpenoid from the fungus <i>Pestalotiopsis clavata</i> JSQ 12 isolated from the mushroom <i>Lanmaoa asiatica</i>

A novel sesquiterpenoid, designated as pestaloclactone (<b>1</b>), along with four previously reported compounds, namely pestaloporinate E (<b>2</b>), pestalotiopsin F (<b>3</b>), pestalotiopsin J (<b>4</b>), and pestaloporinate B (<b>5</b>), was isolated from the culture of the fungus <i>Pestalotiopsis clavata</i> JSQ 12. The structures of these compounds were elucidated primarily through a comprehensive analysis of MS, NMR, and specific rotation data. Furthermore, X-ray diffraction experiment was performed to confirm the absolute configuration of compound <b>1</b>. Notably, the skeleton structure of pestaloclactone (<b>1</b>) is reported here for the first time. The isolated compounds were evaluated for their cytotoxic and antibacterial activities. Compound <b>1</b> demonstrated stronger inhibitory effects on BV2 and SH-SY5Y cells at a concentration of 40 µM, with IC₅₀ values of 28.59 and 37.97 µM, respectively.