Separation and Identification of Catalpol from Rehmannia and its Acute Toxicity Test

Radix Rehmanniae is one of beneficial traditional Chinese medicine.Study on the literatures of iridoid glucosides from Radix Rehmanniae shows that Catalpol has hypoglycemic effect on senile dementia and Parkinson disease.Iridoid glucosides from Radix Rehmanniae have large polarity,and it is difficult to be isolated from their similar structures.Combined the nature of catalpol with the study of literature,the following extraction process was taken: After the recirculation of Rehmanniae glutinosa by acetone,most of saccharide in acetone extracts is gotten rid of by activated carbon column chromatography,and then by silica gel column chromatography,to be crude,finally recrystallized to be catalpol.Then the thin layer chromatography(TLC) and high performance liquid chromatography(HPLC) method were used to determine the catalpol.The purity is 98% while 0.25 μg Catalpol was tested in HPLC.Rf figures and colors of Catalpol are the same with those of standard samples in TLC.Finally,the acute toxicity test of catalpol for mice show the extraction method gains a very good effect of the purification and the catalpol is of little toxicity.