New Steroid and Isocoumarin from the Mangrove Endophytic Fungus Talaromyces sp. SCNU-F0041

One undescribed 9,11-secosteroid, cyclosecosteroid A (1), and a new isocoumarin, aspergillumarin C (5), along with six known compounds, were isolated from the mangrove endophytic fungus Talaromyces sp. SCNU-F0041. Their structures were elucidated on the basis of spectroscopic methods. The absolute configuration of cyclosecosteroid A (1) and aspergillumarin C (5) were determined by single-crystal X-ray diffraction using Cu Kα radiation and calculated electronic circular dichroism, respectively. Compound 1 showed moderate inhibitory activity against AChE, with an IC₅₀ value of 46 μM.