Determination of the content of magnolin in Flos Magnoliae by microwave-assisted extraction and HPLC method

Abstract

Objective: To establish a microwave-assisted extraction and HPLC method for determinination of the content of magnolin in Flos Magnoliae from four different origins.Methods: The magnolin in Flos Magnoliae herbs was extracted by 75% ethanol in microwave for 800 s at the temperature of 76 ℃.HPLC was performed on a Shim-Pack VP-ODS column(150 mm×4.6 mm,5 μm) with mixture of acetonitrile and water(40∶60) as mobile phase.The flow rate was 0.8 ml/min.The column temperature was room temperature.The detection wavelength was 238 nm.Results:The regression equation was A=2.922 7×104 c-3 617.4(r=0.999 9),where A was the peak areas and c was the concentration of magnolin.The concentrations of magnolin in the range of 5.6-240.8 μg/ml were in good linearity with chromatographic peak areas.The precision,reproducibility and stability were all good.The average recovery rates of low,middle and high concentrations(104.87,127.42,172.51 μg/ml) of magnolin were(100.39±1.58)%,(103.82±4.04)% and(103.74±0.13)%(n=3),respectively.This method was used to determine the contents of magnolin in Flos Magnoliae from four different origions: He'nan,Hebei,Hunan and Hubei provinces and the contents were(6.59±0.39)%,(3.44±0.48)%,(2.73±0.28)% and(4.18±0.25)%(n=3),respectively.Flos Magnoliae herbs from He'nan province was found to have the highest content of magnolin.Conclusion: The method is simple,accurate,stable and can be used as a quantitative method for quality control of Flos Magnoliae herbs and its preparations.