Determination of indigo and indirubin in Indigo Naturalis by HPLC

OBJECTIVE To determine the contents of indigo and indirubin in Indigo Naturalis.METHODS The contents of indigo and indirubin were determined by HPLC.The chromatographic column was DiamonsilTM C18(250 mm×4.6 mm,5 μm).The mobile phase was methanol-water(80:20).The flow rate was 1.0 ml·min-1 with detection wavelngth of 287 nm for indigo and 292 nm for indirubin.RESULTS The linear correlation of the indigo was good in the range of 0.07-0.52 μg and the recovery was 100.9% with RSD of 1.42%(n=6).The Linear correlation of the indirubin was good in the range of 0.02-0.20 μg and the recovery was 101.3% with RSD of 1.87%(n=6)。CONCLUSION The method can be applied to determine the contents of indigo and indirubin in Indigo Naturalis.It can ensure the stability of the quality control of Indigo Naturalis.