Determination of ursolic acid and oleanolic acid in Mentha Haplocalyxby RP-HPLC with photodiode array detector

A new HPLC method for determination of ursolic acid and oleanolic acid in Mentha haplocalyx was developed.The Kromasil C18(250 mm×4.6 mm,5 μm) was used as analytical column with methanol-water-phosphate(90∶10∶0.2) as mobile phase.The detection wavelength was set at 210 nm with photodiode array detector.The flow rate was 0.8 mL·min-1 and the column temperature was 28 ℃.The calibration curve of ursolic acid was linear over the range of 0.67-6.03 μg,and the correlation coefficient was 0.999 62.The calibration curve of oleanolic acid was linear over the range of 0.66-5.94 μg,and the correlation coefficient was 0.999 65.The average recoveries of ursolic acid and oleanolic acid were 97.6%(RSD=1.6%) and 99.8%(RSD=2.1%) respectively.The method is simple,accurate and reproducible.It has wide linear range and can be used for the simultaneous determination of ursolic acid and oleanolic acid in M.haplocalyx.