A new vetivane-type sesquiterpenoid with a tricyclic 7/5/5 scaffold from the endophytic fungus <i>Penicillium oxalicum</i> 2021CDF-3

Natural sesquiterpenoids possess a variety of skeleton types with intriguing biomedical activities. In this study, a comprehensive chemical study of the endophytic fungus <i>Penicillium oxalicum</i> 2021CDF-3 yielded a new sesquiterpenoid, namely penicivetivane A (<b>1</b>). The chemical structure for <b>1</b> was thoroughly ascertained by using HRESIMS and NMR spectroscopic analyses, while the stereochemistry of <b>1</b> was further verified by X-ray diffraction analyses. <b>1</b> represented a rare natural vetivane-type sesquiterpenoid with a tricyclic 7/5/5 scaffold. Penicivetivane A (<b>1</b>) displayed strong antimicrobial properties against human pathogens <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, with respective MICs of 4 and 2 μg/mL. This study provided a new vetivane-type sesquiterpenoid with a lead potency for the discovery of anti-infective drugs.