Drimane-type sesquiterpenes with a dioxabicyclooctane skeleton from the fruiting bodies of Nigrofomes melanoporus and their cytotoxicity.

Two new drimane-type compounds, nigrofomins A ( 1) and B ( 2), possessing a rare dioxabicyclooctane moiety, were purified from the fruiting bodies of Nigrofomes melanoporus. Their structures were determined using 1D-, 2D-NMR and HR-ESI-MS spectroscopic analyses. In addition, 1 was established by X-ray crystallographic studies. Both nigrofomins A ( 1) and B ( 2) exhibited cytotoxicity on acute T-cell leukemia (Jurkat), human nasopharyngeal carcinoma (NPC-TW01), and lung cancer (NCI-H661) cells with IC (50) values in the range of 99.44-246.32 µM. Furthermore, the effects of 1 and 2 on cell-cycle progression of Jurkat cells displayed a concentration-dependent accumulation in the G (0)/G (1) phase.