Isolation and simultaneous determination of coumarin compounds in Radix Angelica dahurica

For the first time simple rapid and systematic methods have been established for preparative,, isolation and purification of coumarin compounds in an important traditional Chinese Medicine, Radix Angelica dahurica, and for simultaneous determination of several of the compounds in the medicine. Bergapten, imperatorin, and cnidilin, three of the biologically active coumarin compounds, were isolated from the chloroform-soluble fraction of the ethanol extract of Radix Angelica dahurica. After further purification by open column ODS chromatography the purified components were simultaneously determined, with two other coumarins (osthole and isoimperatorin), by reversed phase high-performance liquid chromatography (RP-HPLC) on a C-18 column, with methanol-water, 66:34 (v/v), as mobile phase at a flow rate of 0.8 mL min(-1). The compounds were detected by UV absorption at 310 nm. Calibration plots for all the coumarins had correlation coefficients close to unity. Limits of detection (S/N = 3) were < 92 ng mL(-1) and limits of quantification (S/N = 10) were < 259 ng mL(-1). Mean recovery of the coumarins was in the range 96.7-101.9% and the intra-day and inter-day precision, as relative standard deviation, was < 2.3 and < 2.9%, respectively. This simple, sensitive, and reproducible method can be used for quality control of Radix Angelica dahurica.