Determination of ursolic acid and ursolic acid lactone in the leaves of Eucalyptus tereticornis by HPLC

a simple isocratic hplc method has been developed for the simultaneous quantification of two bioactive triterpenes, ursolic acid and ursolic acid lactone in e. tereticornis leaves. samples were analyzed on rp-18 (4.6 × 250 mm, 5 μm) column with methanol and water acidified to ph 3.5 with tfa (88:12) at 210 nm. the method was validated and applied for the simultaneous quantification of the individual triterpenes in e. tereticornis extract. the calibration curves were linear over a concentration range of 0.05-0.3 mg ml-1 (r = 0.999 and 0.998, respectively). the limits of detection and quantification were 0.190 and 0.644 μg for ursolic acid, and 0.176 and 0.587 μg for ursolic acid lactone, while the percentage recoveries were 97.32 and 96.23% for ursolic acid and ursolic acid lactone, respectively. this is the first report on the hplc method of ursolic acid lactone with high precision and accuracy.