Analysis of luteolin in Elsholtzia blanda Benth. by RP-HPLC.

The total luteolin content in Elsholtzia blanda Benth. extracts (EBBE) was determined using reversed phase HPLC. C18 was used as the packing material and 0.01 M phosphate buffer (pH 2)-tetrahydrofuran-isopropanol (70:30:5) as the mobile phase with detection wavelength 360 nm. The recovery of the method was 96.4%-101.8%, and the assay was linear at concentrations from 5 to 200 microg/ml (r = 0.9999). The results indicated that the content of luteolin in EBBE extracted under different conditions varied significantly. This method can be used to optimize the extraction procedure and determine the content of luteolin in Elsholtzia blanda Benth. extracts.