Simultaneous Determination of Ursolic Acid, Isoursolic Acid and P-coumaric Acid of Hedyotis Diffusa Willd. by HPLC

OBJECTIVE To establish an HPLC method for the simultaneous determination of ursolic acid, isoursolic acid and p-coumaric acid in Hedyotis diffusa Willd.. METHODS Diamonsil C₁₈ ODS (4.6 mm×250 mm, 5 μm) was used; mobile phase was acetonitrile and 15 mmol·L^-1 NH₄AC(12∶88, pH3.5); flow rate: 1.0 mL·min^-1; wavelength: 308 nm; column temperature: 35 ℃. RESULTS Three ingredients showed good linear relationships, ursolic acid: 0.075 7-2.271 μg (R²=0.999 6), isoursolic acid: 0.010 3-0.309 μg (R²=0.999 2) and p-coumaric acid: 0.020 2-0.606 μg (R²=0.999 6), with the mean recoveries as 99.9% (RSD=0.7%), 99.0% (RSD=1.7%) and 101.1% (RSD=0.7%), respectively. CONCLUSION This method is simple with high precision, repeatability, and stability, so it can be used to quantitative analysis and quality control of Hedyotis diffusa Willd.