Abstract: To establish a rapid and efficient method for isolation and purification of luteolin-7-O-β-D-glucuronide (L7GU) from herb of Ixeris sonchifolia (Bge) Hance,a preparative medium pressure liquid chromatography (MPLC) method was developed and used.The MPLC system consisted two-unit pumps and a glass column (φ49 mm×H310 mm) linked with cone-shaped stainless steel port and packed with C₁₈ particles (Chromatorex,MB 100-40/75).The mobile phase was methanol (A)-water (containing 0.05% acetic acid,B).The gradient elution program was as follows:0-20 min,10%A; 20-23 min,30%A;23-27 min,60%A;27-30 min,100%A.The flow rate was 50 mL/min,and the detection wavelength was set at 254 nm.The structure of isolated L7GU was subsequently confirmed by analyzing its UV,IR,TOFMS, ¹H-NMR and ¹³C-NMR.Silica gel HPTLC,polyamide TLC and HPLC analyses were performed to test and verify the purity of isolated L7GU.One single yellowish green spot under UV at 365 nm was detected in both TLC analyses.The HPLC analyses at detection wavelength of 210 nm,254 nm,290 nm and 348 nm demonstrated the purity of isolated L7GU was more than 98%.The high-purity L7GU prepared by this method can be used as reference substance for the quality control of herb of I.sonchifolia and its proprietary medicine.

Key words: Ixeris sonchifolia, Kudiezi, luteolin-7-O-&beta, -D-glucuronide, isolation, preparative liquid chromatography