Simultaneous Determination of Oleanolic Acid and Ursolic Acid in Leaves of Paulownia by HPLC

A quick and accurate HPLC method has been developed for the simultaneous quantification of two bioactive triterpenes, ursolic acid and oleanolic acid in Paulownia leaves. The samples were analyzed on a Shim-pack ODS-CLC (M) (4.6 mm × 250 mm, 5 μm) column kept at 21 °C, using the methanol and aqueous phase containing 0.05%phosphoric acid with the volumetric ratio of 91.7:8.3 as the mobile phase at a flow rate of 0.6 mL/ min, and the detection wavelength was set at 210 nm. The method was validated and applied to the simultaneous quantification of the two triterpenes in Paulownia leaf extract. The standard curves were established in the range of 0.44 ~ 8.75 μg for oleanolic acid and 0.92 ~ 18.37 μg for ursolic acid. The contents of oleanolic acid and ursolic acid in leaves of Paulownia were determinated using the HPLC method and the contents were 3.87 mg/g and 13.61 mg/g, respectively.