Bioactive Pyranones Isolated From the Mangrove-Associated Endophytic Fungus Aspergillus sp. H6a.

Chemical investigation of the mangrove endophytic fungus Aspergillus sp. H6a led to the isolation of six new compounds, including four naphtho-γ-pyrone dimers, aurasperones I-L (1-4), a monomeric precursor, rubrofusarin C (5), and a coumarin, ascoumarin A (6), along with 12 known analogues (7-18). Their structures and absolute configurations were established by spectroscopic data, ECD analysis, and the modified Mosher's method. Compounds 1-17 were evaluated for their cytotoxicity against A549 cancer cells using the CCK-8 assay. Compound 10 showed the most potent activity, with an IC50 value of 11.27 µM, comparable to cisplatin (DDP) (14.35 µM). In DDP-resistant A549/DDP cells, compound 10 retained potent activity with an IC50 value of 12.58 µM, markedly lower than that of DDP (40.19 µM), and further enhanced the inhibitory effect of DDP when used in combination. These findings expand the chemical diversity of mangrove-derived Aspergillus species and offer a candidate for overcoming DDP resistance.