Abstract: The extraction process of dihydroartemisinic acid (DHAA) from the remainder of Artemisinin extract was optimized.Taking the yield of extract and the purity of dihydroartemisinic acid in the extract as indexes,the influencing factors such as the types and concentrations of extraction solvents,extraction temperature,the types and concentrations of alkali liquor for increasing the solution pH were investigated,a L₉(3⁴) orthogonal experiment was applied to explore the optimal process.The results indicated that,the mass of extract obtained by ethanol as solvent was obviously greater than that of acetone as solvent.The optimal process parameters were as follows:applying 80% (V/V) ethanol as solvent and the extraction temperature at 50 ℃;applying 1% (w/w) sodium hydroxide solution as alkali liquor.Under these conditions,more than 70% dihydroartemisinic acid in the remainder of Artemisinin extract was recovered,the purity of the product reached 98% analyzed by HPLC analysis

Key words: Artemisia annua L., dihydroartemisinic acid, artemisinin, extraction remainder, process optimization