Cytotoxic Illudalane Sesquiterpenes from the Wood-Decay Fungus Granulobasidium vellereum (Ellis & Cragin) Julich

Seven illudalane sesquiterpenes were obtained from the wood decomposing fungus Granulobasidium vellereum: granuloinden A, granuloinden B and dihydrogranuloinden, along with the previously known compounds radulactone, pterosin M, echinolactone A and D. Granuloinden B showed potent cytotoxic activity against the Huh7 and MT4 tumor cell lines (CC50 values of 6.7 and 0.15 mu M, respectively), whereas granuloinden A and dihydrogranuloinden had no or moderate activity.