bitter drimane-type sesquiterpenoids with an isocitricacid group named cryptoporicacids (CA) A-G have been isolated from the fungus Cryptoporous volvatus and their absolute stereostructures established by a combination of chemical transformation, NMR spectral data and X-ray crystallographic analysis. Cryptoporicacids strongly inhibited the release of superoxide anion radicals from guinea-pig peritoneal