Anti-inflammatory activities of furanoditerpenoids and other constituents from Fibraurea tinctoria.

Five new furanoditerpenoids, epi-8-hydroxycolumbin (1), fibaruretin B (2), C (3), E (5), and F (6), were isolated from the stems of Fibraurea tinctoria, as well as fibaruretin D (4) from the natural source for the first time, and 39 known compounds. The structures (1-6) were elucidated on the basis of spectroscopic analysis. All the isolated furanoditerpenoids (1-16) were examined for their in vitro activity and some were in vivo anti-inflammatory activity. Compounds 8 and 9 showed significant anti-inflammatory action administered at a dose of 100mg/kg of reducing carrageenan mice paw edema, whereas compound 7, 9, 10, 14, and 16 were more potent to inhibit NO production. The inhibitory effects of these compounds are dose-dependent (1-4 microg/ml).