HPLC analysis were performed using a liquid chromatograph (Waters, model 600E), a Rheodyne 7125 injection valve with a 20 mL loop, a 486 UV variable-wavelength detector (set at 203 nm) and a Waters 747 integrator. Ursolic acid was analyzed using a Novapack® column C-18, 4 µm, 150 mm x 3.9 mm i.d. The mobile phase consisted of a mixture, acetonitrile:water (70:30, v/v). The solution was degased in an ultrasound bath and filtered under vacuum through a membrane (Millipore, PVDF). The flow was of 1.0 mL min-1 and the sensitivity was 0.001 AUFS. The HPLC system was operated at room temperature (23 ± 1 °C).