[Determination of diosgenin in Rhizoma Paridis by high performance liquid chromatography]

A method for the separation and determination of diosgenin in Rhizoma Paridis by reversed-phase high performance liquid chromatography was developed. The Rhizoma Paridis powder samples were extracted with methanol in a Soxhlet extractor. After extraction the solvent was evaporated and the extract was hydrolysed with 2 mol/L hydrochloric acid for 2 h in a boiling water bath. Then the diosgenin was extracted with petroleum ether (b.p. 60-90 degrees C). The operating conditions were Symmetry C8 column (5 microns, 3.9 mm x 150 mm) at 30 degrees C, mobile phase of V(acetonitrile):V(water) = 75:25 and UV detector at 203 nm. The linearity of the calibration curve was good in the range of 2.1-10.5 micrograms for diosgenin(r = 0.9994). The average recovery and RSD of diosgenin were 99.1% and 1.7% (n = 5) respectively. The method is accurate and reproducible and has been applied to the analysis of Rhizoma Paridis from different sources.