Optimizing Process of Radix Salvia Miltiorrhiza Ethanol Precipitation by Response Surface Methodology

OBJECTIVE To optimize the process of ethanol precipitation of extraction of protocatechua-ldehyde. METHODS An effective two-phase statistical approach to enhance extracting rate. In the first phase, Plackett-Burman design was undertaken to evaluate the effects of the eight factors: namely density of Radix Salvia Miltiorrhiza extract, first ethanol precipitation rate, ethanol concentration of first alcohol precipitation, density of condensed alcohol precipitation, second ethanol precipitation rate, ethanol concentration of second alcohol precipitation, concentration of sodium hydroxide solution and pH. By regression analysis, density of Radix Salvia Miltiorrhiza extract, density of condensed alcohol precipitation and pH were found to be important for extraction of protocatechualdehyde. In the second phase of the optimization process, a three-level three-factor Box-Behnken design was used to optimize the above critical internal factors. RESULTS The results showed that the maximum experimental value of protocatechualdehyde (0.487 mg·mL^-1) can be obtained. CONCLUSION This extraction technology could be used for the extraction of protocatechualdehyde in the process of Radix Salvia Miltiorrhiza ethanol precipitation.