Sesquiterpenes from cultures of the fungus Phellinus igniarius and their Cytotoxicities.

Four new sesquiterpenoids, phellinignins A-D (1-4), together with four known ones (5-8), were isolated from cultures of the fungus Phellinus igniarius. The structures were established by extensive spectroscopic methods including MS, NMR, and the single crystal X-ray diffraction. Compounds 1-3 and 5-8 are tremulane sesquiterpenoids, while compound 4 possesses a new carbon skeleton that might derive from an illudane framework. Compounds 1, 2, 4, and 5 showed certain cytotoxicities to three human cancer cell lines.