Chemical investigation of the Daphne genkwa has led to the isolation of four sesquiterpenes (1a/1b, 2 and 3), including one pair of sesquiterpene enantiomers (1a/1b), 1a is a new compound (+)-4-hydroxy-10-epirotundone, and twelve lignans (4-15). Their structures were elucidated by spectroscopic analysis, and the absolute configurations of 1a/1b were determined by CD analysis. All compounds were examined for their inhibitory effects on the nitric oxide (NO) production induced by lipopolysaccharide (LPS) in BV-2 microglial cells, and compounds 7-10 exhibited pronounced inhibition on NO production with IC50 values in the range of 5.8-10.2 μM, being more active than the positive control, quercetin (IC50 = 17.0 μM).
Keywords: lignan; nitric oxide; sesquiterpene.