Determination and structural elucidation of sesquiterpene lactones from Inula racemosa

Key words: 
• Inula racemosa /
• sesquiterpene lactone /
• igalane /
• isoalantolactone /
• alantolactone /
• HPLC /
• isomer

Abstract: Objective To establish a method of HPLC for the simultaneous quantification of three sesquiterpene lactones in Inula racemosa. Methods Agilent Zorbax XDB-C₁₈ column(250 mm×4.6 mm,5 μm) was uesed with a mobile phase consists of 55% acetonitrile and 45% water,at a flow rate of 1.0 ml/min,and detection wavelength of 210 nm. Results Three sesquiterpene lactones in Inula racemosa Hook.f.,namely igalane(1),isoalantolactone(2) and alantolactone(3) has good linear relation in 17.40～1 740.00,21.20～2 120.00,20.40～2 040.00 μg/ml with the lowest detection limit of 0.087,0.042,0.041 μg/ml respectively.The RSD of repeatability and stability were all less than 2.85%.The average recovery rate of there constituents were all less than 104.43% with RSD less than<1.20%. Conclusion The method was rapid,accurate,reliable and could be suitable as a quality control method for I.racemosa.Two minor isomers from I.racemosa were isolated by semi-preparative HPLC which structures were elucidated on the basis of NMR analysis.