HPLC Determination of Diosgenin in Dioscorea Zingiberensis

Dioscorea zingiberensis was refluxed with dil.H2SO4 to liberate diosgenin from the sample,and after neutralization with dil.NaOH solution,the sample solution together with the insoluble residue was extracted with methanol as solvent using the ASE200 Extractor.The methanol extract was diluted to 50 mL with methanol in a volumetric flask and a 10 μL aliquot was taken for HPLC determination.Chromatographic separation was carried out on the YWG C18 column using methanol-H2O (95+5) as mobile phase.UV-detection at the wavelength of 210 nm was adopted in the determination with external standard method.Linearity range of the method was from 0.01 to 2.93 g·L-1,with detection limit of 0.2 mg·L-1.Values of recovery of this method were found in the range of 97.1%-99.8%,and values of RSD′s (n=7) obtain from the results of analysis of 4 substantial samples were in the range of 1.1%-1.5%.