Abstract
Six previously undescribed sesquiterpenoids, aurantiophilanes A-F (1-6), along with six identified analogues (7-12), were isolated from the fungus Aspergillus aurantiobrunneus. Among these, compounds 1 and 3 were identified as highly oxygenated eremophilane sesquiterpenoids, with compound 1 featuring a rare ketone functional group at C-1. The structures of all compounds were unambiguously elucidated using comprehensive spectroscopic analyses, including HRESIMS, NMR, and UV spectroscopy, supplemented by electronic circular dichroism (ECD) analyses and single-crystal X-ray diffraction. All identified compounds were evaluated for immunosuppressive activity; none showed significant effects at concentrations up to 40 µM.