New cassane-type diterpenoids with anti-inflammatory activity from the seeds of Caesalpinia sinensis

Three undescribed cassane diterpenoids, caesall FA/FB (1/2) and caesalpin LO (3), along with known pterolobirin G (4/5), were separated from the seed kernels of Caesalpinia sinensis. Their structures were unambiguously identified in the light of extensive spectroscopic data. Bioactively, all the compounds were evaluated for their inhibitory effects against overproduction of NO in LPS-simulated RAW 264.7 cells by the Griess reaction. Compounds 1/2 and 4/5 exerted excellent anti-inflammatory efficacy with IC₅₀ values of 5.8 and 7.1 μM.