Objective: To determine two main active constituents

dihydromyricetin and myricetin

in Tengchasu extracts which are derived from Ampelopsis Grossdentatae Caulis

and to provide scientific basis for the development and utilization of Ampelopsis Grossdentatae Caulis. Method: ODS was used as stationary phase

the mobile phase consisted of methanol and 0.1%H3PO4 water solution

and a gradient elution was used. The detection wavelengths were set at 291 nm for dihydromyricetin and 375 nm for myricetin. Result: The content of dihydromyricetin in the extract from the tender leave was higher than that from the aerial parts

and simple stir-fried can make the content of dihydromyricetin in the extract from the tender leave increased

but as the decocting time extended

the content of dihydromyricetin in the extract decreased. Conclusion: The preparation methods and decocting time have great influences on the content of the active ingredients in tengchasu extracts.