New cassane-type diterpenoids with anti-inflammatory activity from the seeds of <i>Caesalpinia sinensis</i>

Three undescribed cassane diterpenoids, caesall FA/FB (<b>1/2</b>) and caesalpin LO (<b>3</b>), along with known pterolobirin G (<b>4/5</b>), were separated from the seed kernels of <i>Caesalpinia sinensis</i>. 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 <b>1/2</b> and <b>4/5</b> exerted excellent anti-inflammatory efficacy with IC₅₀ values of 5.8 and 7.1 μM.