Abstract: Objective: To establish a HPLC method to determine the contents of oleanolic acid (OA) and ursolic acid (UA) in different organs of Paeonia lactiflora Pall.. Method: Oleanolic and ursolic acids were extracted from samples with ethanol under the assistance of ultrasonic. The chromatographic separation was conducted on a Lichrospher C18 column (250 mm × 4.6 mm, 5μm) using a mobile phase made up of methanol and 0.1% phosphoric acid solution (85:15, V/V) at a flow rate of 1 mL/min. The column temperature and the detection wavelength were set as 30 ℃ and 210 nm, respectively. Results: The linearity of OA and UA was in the range of 25－100μg/mL with a correlation coefficient over 0.998 (n = 5). The overall intra-day and inter-day variation coefficients were 1.46%－2.84% and 1.33%－3.32% for OA and 1.27%－2.96% and 1.97%－3.64% for UA, respectively. The accuracy of determination of OA and UA was 1.28%－3.52% and 0.96%－2.88%, respectively. Conclusion: The method is convenient, rapid and accurate, and can thus be used to separate and quantify OA and UA in different organs of Paeonia lactiflora Pall..

Key words: high performance liquid chromatography (HPLC), Paeonia lactiflora Pall., oleanolic acid, ursolic acid