Arugosins G and H:: Prenylated polyketides from the marine-derived fungus Emericella nidulans var. acristata

The fungus Emericella nidulans var. acristata was isolated as an endophyte from a Mediterranean green alga. Cultivation of this fungus yielded two new compounds, arugosins G ( 1) and H ( 2), together with the known metabolites 3-9. Arugosins (1-4) are benzophenone derivatives, biosynthetically related to the xanthones 5, 6, and 9. The indole alkaloid 7 displayed antitumor activity in a panel of 36 human tumor cell lines, exhibiting a mean IC50 value of 5.5 mu g/mL in an in vitro survival and proliferation assay. Furthermore, compounds 3 and 4 showed moderate antitumor activity toward individual tumor cell lines. None of compounds 1-8 exhibited any immunostimulatory activity assessed as the capacity to induce cytokines in PBMCs from healthy donors.