Determination of catalpol in radix rehmanniae from different sources by HPLC

Objective To determine the content of catalpol in radix rehmanniae from different sources.Methods Catalpol in radix rehmanniae was determinated by high performance liquid chromatography.The mobile phase consisted of methyl alcohol-0.1% phosphoricacid(1∶ 99) with the flow rate of 1.0 ml·min-1.The detection wavelength was at 210 nm and column temperature was 35℃.Results Good linearities were obtained over the range between 25 and 250 mg·L-1 for catalpol.The average recovery of glycyrrhizic acid was 95.66%(RSD=1.52%,n=9).Conclusion Content of catalpol is variant in different sources.The content of catalpol in radix rehmanniae is higher than that of radix rehmanniae preparata.