RESUMEN
Objective To study the chemical constitutents of Fomes officinalis and their inhibiting (effect) on thrombin. Methods Compounds were separated by column chromatography with silica gel and polyamide, whose structures were elucidated by spectral analysis and chemical evidence. Results Seven compounds were isolated from the chloroform extract. Their structures were identified as: 3-keto-dehydrosulfurenic (Ⅰ), dehydroeburicoic acid (Ⅱ), eburicoic acid (Ⅲ), sulphurenic acid (Ⅳ), dehydrosulphurenic acid (Ⅴ), dehydroeburiconic acid (Ⅵ), versisponic acid D (Ⅶ). The inhibitory rate of compound Ⅶ on thrombin was 45.36% but others were not obvious. Conclusion Compounds Ⅴ, Ⅶ are isolated from the fungus for the first time. Compound Ⅶ is effective to anti-thrombin at higher concentration, while the remainders are not obvious.