Objective: To develop a method for the determination for three prototype constituents into the blood from the extract of Rehmannia glutinosa. Method: The prototype constituents into the blood from R. glutinosa were confirmed by using the method of serum pharmacochemistry

and then the extracts were determined by HPLC. Inertsil ODS-SP C18 column (4.6 mm×250 mm

5 μm) was used with acetonitrile-water as mobile phase; the column temperature was kept at 35℃

and flow rate was 1 mL·min-1. The detection wavelength was set at 203 nm. Result: It was found that in rat serum catalpol

rehmannioside D and leonuride could enter into the blood in prototype forms. The calibration curves of catalpol

rehmannioside D and leonuride were within 0.32-1.60 μg (r=0.999 6)

0.406-2.03 μg (r=0.999 8)

0.8-4.0 μg (r=0.999 8). The average recoveries were 99.74% (RSD 2.53%)

96.14% (RSD 1.31%) and 100.10% (RSD 2.73%) respectively. Conclusion: The developed methods are simple

feasible and repeatable. They are used to determine three components from 12 batch extracts of R. glutinosa in Jiaozuo district

Henan Province. The maximum total content is 20.28%

and the minimum one is 11.32%. Suggestion that the total content of these three components from the extract of the R. glutinosa must not be less than 15% is provided.