Simultaneous Determination of Indigo and Indirubin in Medicinal Material of Indigo Naturalis

Objective To establish a HPLC method for simultaneous determination of indigo and indirubin in medici-nal material of Indigo Naturalis,and to improve the quality standard of Indigo Naturalis in Chinese Pharmacopeia of 2010 edition,volume I.Methods We use suitable amount of DMF to extract indigo and indirubin from Indigo Natu-ralis simultaneously by ultrasonography for 30 min.HPLC condition were as follows :Kromasil C 18(250 mm×4.6 mm,5 μm),mobile phase of acetonitrile ∶ wate(r70 ∶ 30),column oven temperature at 30 ℃,and detection wavelength at 290 nm.The above HPLC conditions had no effect on the analysis result but could greatly shorten analysis time.Results The linear correlation of the indigo was good in the range of 29.90 ng~298.90 ng and the recovery was 101.05 %(RSD=1.81 %).The Linear correlation of the indirubin was good in the range of 6.71 ng~67.06 ng and the recovery was 99.78 %(RSD=2.52 %).Conclusion This method is simple,rapid and effective for simultaneous determination of indigo and indirubin in Indigo Naturalis,which meets the requirement of current pharmacopoeia.