Response Surface Methodology as an Approach to Optimize Catalpol Extraction from Radix Rehmannia glutinosa

Objective: To optimize the process parameters of solvent reflux extraction of catalpol from Radix Rehmannia glutinosa.Methods: On the basis of one-factor-at-a-time experiments,response surface methodology(RSM) was used for process parameter optimization.A regression model was established describing catalpol extraction yield as a response to various process parameters.Results: The optimal extraction conditions were 72.94% methanol aqueous solution as the extraction solvent,extraction temperature 54.8 ℃,extraction time 3.0 h and number of repeated extractions 2.Under these conditions,the catalpol extraction yield was 3.513%.Conclusion: The established regression model can accurately and conveniently predict catalpol extraction yield.The optimal extraction process obtained is efficient and feasible.