Abstract Scrophulariaceae plant to Radix Rehmanniae is an important commonly used traditional Chinese medicine replenishing, catalpol as the main component in yellow, are iridoid glycosides category. Documents show that its research on experimental diabetes have hypoglycemic effect. Fresh Huang iridoid glycosides compounds structurally similar, more polar, but poor stability, the more difficult separation. This subject to Chinese herbal medicine and Huang were used as raw material methanol return macroporous resin adsorption; methanol dissolved, ultrasonic extraction; ethanol gradient elution methods such as extraction, activated carbon adsorption, and Huang discussed in extracting the best catalpol Process. A high performance liquid chromatography analysis to identify, through Catalpol yield, reached the following conclusions: three times the volume of 80 percent ethanol, ultrasonic extraction 45 minutes, extracts of using macroporous resin D101 adsorption, and Ethanol gradient elution, condensed, dry, Catalpol the yield: 0.32 percent.
Key words: fresh yellow; Catalpol; macroporous resin; activated carbon and diatomite; HPLC;