Coumarinolignoids and Taraxerane Triterpenoids from Sapium discolor and Their Inhibitory Potential on Microglial Nitric Oxide Production

Seventeen compounds, including three new pairs of coumarinolignoid enantiomers, (7′S,8′S)-sapiumins A–C (1a–3a) and (7′R,8′R)-sapiumins A–C (1b–3b), six new taraxerane triterpenoids, sapiumic acids A–F (4–9), and five known taraxerane triterpenoids (10–14), were isolated from an ethanol extract prepared from the stems and leaves of Sapium discolor. The structures of 1–9 and their relative configurations were determined by spectroscopic data analysis, and the absolute configurations of the coumarinolignoids 1a/1b–3a/3b and triterpenoids 6–9 were assigned using experimental and calculated ECD data. Compounds 1a/1b–3a/3b are the first coumarinolignoids to be reported from the genus Sapium. Among all the isolates, compounds 1b, 2a/2b, 3a/3b, and 6–9 inhibited nitric oxide production in lipopolysaccharide-stimulated BV-2 microglial cells, with IC50 values of 1.7–15.3 μM.