Determination of Catalpol in the Different Prepared Medical Materials of Rehmannia glutinosa by TLCS

Objective:To determine catalpol contents in the different prepared medical materials of Rehmannia glutinosa.Methods:The contents were determined by TLCS with the use of dual wavelength reflection zigzag scanning.Silica gel G was employed as the stationary phase, and a mixed solvent of EtOAc-MeOH-HAc-H 2O(10∶2∶0.5∶0.5) was used as the developer.The scanning was performed at λ S 540 nm and λ R 650 nm.Results:The difference of catalpol contents in the different prepared medical materials of Rehmannia glutinosa was obvious.The contents were in the decreasing order of raw Rehmannia (0.55%)dried Rehmannia (0.22%)prepared Rehmannia (0.13%).Conclusion:This method is simple, sensitive and repeatable.It is suitable for the quality control of rehmannia and its preparations.