Abstract: Corosolic acid is clinically proven to activate cell glucose-transporter “shuttles” and thus helps balance blood glucose levels. A method was developed for the determination of corosolic acid in Eriobotrya japonica leaves by reversed-phase high performance liquid chromatography (RP-HPLC). The peak of corosolic acid in Eriobotrya japonica leaves was qualitatively analyzed by comparing the retention times and mass spectra of corosolic acid standard and the extract on HPLC-mass spectrometry (MS). Eriobotrya japonica leaves were extracted thrice for 3.0 h at 90 ℃ with 90% ethanol. The extract was concentrated and deposited by water to remove the impurity which interfered the determination. The deposit was dissolved by methanol and separated on an ODS column (250 mm×4.6 mm i.d., 5 μm). Methanol-1.0%acetic acid (88∶12, v/v) was used as the mobile phase with a flow rate of 0.8 mL/min. The detection wavelength was 215 nm. The linearity was good within the range of 1.0-6.0 μg (r=0.9999). The corosolic acid content of Eriobotrya japonica leaves from Huangshan was 0.36%. The average recovery of corosolic acid was 99%. The method is simple, rapid, accurate and reliable for the determination of corosolic acid in Eriobotrya japonica leaves.

Key words: corosolic acid, Eriobotrya japonica leaves , reversed-phase high performance liquid chromatography(RP-HPLC)