Determination Methods of Rehmanniae Radix by HPLC

Objectives : Rehmanniae Radix has been used to clear of latent heat and supply yin for a several thousand years. The using types of Rehmanniae Radix are fresh and dried, steam processed. We have studied on the determination methods of Rehmanniae Radix by HPLC. Methods : The Rehmanniae Radix was dried and prepared from the steaming process with diluted ethanol. The herb extract were 5 classes of difference extracting methods that were reflux and sonication in water and methanol respectively, sonication in 30%methanol. And analysis of 5- hydroxymethyl--2- furaldehyde(5~~H~,.IF) and catalpol was conducted by HPLC with reversed-phase C18 column and a LV detector at B3nm and 204nm. Elution was carried out at l.Oml/min with acetonitrile and methanol. water. Results and Conclusions : From this analysis, we found out that the content of 5-HMF was inceased with extration in reflux. Catalpol can be extracted much in water than in methanol. Sonication in 3090methanol for 2h was the better extraction method that can extracted catalpol and 5-HMF at the same time. And 3YGacetonitrile of mobile phase was good resolution and could analyze into catalpol and 5HMF at the same time.