New anti-mesothelioma compounds, paramyfurans and paramylactone, produced by Paramyrothecium sp. BF-1049

Two new 2-benzylfuran compounds, designated as paramyfurans A (1) and B (2), and a new dihydrocoumarin compound, designated as paramylactone (3), along with abscisic acid (4), were isolated from the culture broth of the fungal strain Paramyrothecium sp. BF-1049. The planar structures of 1, 2, and 3 were elucidated based on spectroscopic analyses, including 1D and 2D NMR. Compound 3 was further separated into its enantiomers, namely (+)-paramylactone ((+)-3) and (-)-paramylactone ((-)-3), by HPLC using a chiral column. Their absolute stereochemistry was determined by comparing calculated and experimental ECD spectra. Compounds 1-4 exhibited cytotoxic activity against three mesothelioma cell lines (NCI-H2452, NCI-H2052, and Y-MESO-27), with IC₅₀ values ranging from 0.68 to 19.86 μM.