Abstract: Ursolic acid (UA) and oleanolic acid (OA) in Rosmarinus officinalis were separated and determined by RP-HPLC-PAD. HPLC assay was performed on Kromasil C18 column (4.6 mm×250 mm, 45μm) and the two compounds were detected at 210 nm using methanol-water-phosphoric acid (88:12:0.1) as mobile phase at a flow rate of 0.8 mL/min and the column temperature was set at 30 ℃. An average recovery of 100.6% was obtained with RSD of 1.6% in the sample injection volume range of 0.10－4.00μg for UA, and an average recovery of 98.7% was obtained with RSD of 1.2% in the sample injection volume range of 0.05－2.00μg for OA. The determination results of samples showed that the method was sensitive, repeatable and accurate, and could therefore be used for the determination of the two triterpene acids in Rosmarinus officinalis.

Key words: Rosmarinus officinalis, ursolic acid, oleanolic acid, HPLC, photodiode array detector