Two new chromone-derived polyketides phaseolorins, G and H (1 and 2), and one new anthraquinone derivative, phaseolorin I (3), together with three known compounds (4-6), were isolated from the deep-sea sediment-derived fungus Diaporthe phaseolorum FS431. The structures of the new compounds were determined by comprehensive analysis of their spectroscopic data, and the absolute configuration of 1 was established by quantum chemical calculations of electron capture detection (ECD). All the isolated compounds (1-6) were tested for their in vitro cytotoxic activities against four human tumor cell lines, of which compound 4 exhibited significant effect against MCF-7, HepG-2, and A549 tumor cell lines with IC50 values of 2.60, 2.55, and 4.64 µM, respectively.
Keywords: Diaporthe phaseolorum; cytotoxicity; deep-sea derived fungus; polyketides.