Four New Cadinane-Type Sesquiterpenoids From the Roots of Fissistigma tientangense

Four new cadinane-type sesquiterpenoids, named fisscadinanes A-D (1-4), together with four known biogenetically related cadinane-type sesquiterpenoids (5-8) were isolated from the roots of Fissistigma tientangense. The structures of these sesquiterpenoids were determined by comprehensive spectroscopic analyses. Compound 1 is a 15-norcadinane sesquiterpene containing one p-π-π-system. Compounds 2-4 are cadinane sesquiterpenes. The absolute configurations of compounds 1-4 were determined via ECD calculations. The inhibitory activities of fisscadinanes A-D against the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in mouse macrophage RAW 264.7 cells in vitro were evaluated. Compounds 1 and 7 exhibited significant inhibitory activities, possessing the IC₅₀ values of 8.27 ± 0.09 and 14.66 ± 0.08 µM. The positive control, quercetin, displayed an inhibitory activity against NO production with an IC₅₀ value of 14.87 ± 0.11 µM.