Furanocoumarins from the root of Angelica dahurica

Five furanocoumarins including a new one were isolated from the root of Ang elica dahurica by repeated silica gel column chromatography. Their chemical structures were determined to be isoimperatorin (1), oxypeucedanin hydrate -3"-butyl ether (2), imperatorin (3), knidilin (4), and oxypeucedanin hydra te (5). This represents the first study in which the compound 2 has been is olated and identified. The long-range coupling ((5)J) in the H-1-NMR spectr um observed in the linear furanocoumarin skeleton was also investigated in detail.