Four New Pyranones from the Sponge-Derived Fungus Aspergillus versicolor

Abstract

Four novel pyranone derivatives were isolated from fungi associated with the marine sponge species Aspergillus versicolor. The planar structures of these compounds were elucidated through comprehensive spectroscopic techniques, including HRESIMS, UV, IR, and 1D and 2D NMR. The absolute configuration of compound 1 was determined via X-ray diffraction, while that of compound 3a was determined using electronic circular dichroism (ECD) spectroscopy. Furthermore, all compounds were evaluated for their cytotoxic activity against human lung carcinoma cells (A549). At 30 μM, only compound 2 exhibited slight cytotoxic activity, with an inhibition rate of (46 ± 3.63)%, compared to doxorubicin (positive control, (86 ± 1.81)%). In DPPH free radical scavenging assays, compound 2 demonstrated a superior capacity than other derivatives, with a scavenging rate of (21.5 ± 3.03)% at 0.6 mg/mL, though still lower than vitamin C ((38.4 ± 2.96)%). Compounds 1, 3a, and 3b exhibited diminished scavenging activities, with rates of (16.1 ± 1.32)%, (13.6 ± 1.60)%, and (15.2 ± 2.79)%, respectively.