Determination of Pinoresinol Diglucoside in Eucommie ulmoides Immunoenhancement Liquids by RP-HPLC

The assay was aimed to determine the content of pinoresinol diglucoside (PDG) in Eucommie ulmoides immunoenhancement liquids. The chromatographic conditions were as follows:Inersustain^® C18 column (250 mm×4.6 mm,5 μm) was under column temperature of 35℃, the mobile phase consisted of acetonitrile-0.2% phosphoric acid(15:85)with a flow rate of 1.0 mL/min,and the UV detection wavelength was 277 nm. Ethyl acetate was used as extraction solvent. In order to determine PDG of the test solution under the chromatographic conditions, the number of theoretical plates and resolution were used as system suitability indicators. Linear regression on reference substance (PDG),linearity range and the precision, stability, and reproducibility of the analysis method, the recovery test of adding samples were all determined. The results showed that under the content determination method, the number of theoretical plates of PDG in the test solution was 8 588, and the resolution was 3.046. PDG performed good linear relation at the linear range between 6 and 192 μg/mL, and the related coefficient was 0.9996. The precision experiments showed that the relative standard deviation (RSD) of reference substance solution was 0.74%. The RSD of reproducibility and stability of PDG in the test solution was 4.50% and 2.69%, respectively. The average recovery was 98.74% with RSD 0.65% (n=9). Under the chromatographic conditions established above, the contents of PDG in the test sample were between 0.124 and 0.127 mg/mL. The conclusion was that the RP-HPLC method performed well system suitability, precision, reoroducibility, stability, and high recovery rate. Meanwhile this method was quick, simple and reliable. It could be used to determine the content of PDG in Eucommie ulmoides immunoenhancement liquids.