Apiosporapyrones A–E: α-Pyrone Derivatives from the Sponge-Associated Fungus Apiospora arundinis P-1 with Growth-Inhibitory Effects on MCF-7 Cells

Five undescribed α-pyrone derivatives, apiosporapyrones A–E (1–5), and ten previously reported compounds (6–15) were obtained from the marine sponge-associated fungus Apiospora arundinis P-1, isolated from a marine sponge Haliclona sp. The structures of 1–5 were elucidated by IR, NMR, and HR-ESI-MS analyses, and the absolute configurations of the stereogenic centers in 1–5 were established by single-crystal X-ray diffraction analysis or comparison between the calculated and experimental ECD spectra. Evaluation of their growth-inhibitory effects against MCF-7 human breast cancer cells identified apiosporapyrone C (3) as the most active compound with an IC50 value of 4.29 µM (IC50 of doxorubicin, the positive control, was 0.76 µM). Preliminary cellular studies showed that 3 suppressed colony formation, induced concentration-dependent apoptosis reaching 70.18% at 10 µM, and increased the G2/M-phase population. These findings expand the pharmacological profile of sponge-associated fungal α-pyrones and highlight apiosporapyrone C as a scaffold for further anti-cancer investigation.