Asperacunoid A, a new cytotoxic germacrane-type sesquiterpenoid isolated from Aspergillus aculeatinus 2022EX723.

Sesquiterpenoids have obtained widespread concern because of their intriguing molecular architecture and considerable bioactivities. In the present study of chemical diversity of Aspergillus aculeatinus 2022EX723, an endophytic species derived from the marine green algae Enteromorpha prolifera, three sesquiterpenoids including a new germacrane-type sesquiterpenoid asperacunoid A (1) and two sesquiterpenoids (2 and 3) were isolated and identified. With the assistance of spectroscopic analyses (HRESIMS, NMR, and X-ray analyses), the structures as well as the absolute configuration of 1 were successfully elucidated. Cytotoxic assays against A549, HeLa, HXO-Rb44, and MKN-45 cell lines revealed that asperacunoid A (1) was active against HXO-Rb44 and MKN-45 cells, with respective IC50s of 10.9 and 23.8 μM (compared with the positive control doxorubicin with IC50s of 11.2 μM for HXO-Rb44 and 13.3 μM for MKN-45 cells). This study indicated that the new sesquiterpenoid 1 may be served as a lead compound with high pharmacological potentiality.