Application of response surface methodology to optimise ultrasonic-assisted extraction of four chromones in Radix Saposhnikoviae.

INTRODUCTION: Radix Saposhnikoviae is one of the most famous Chinese herbal medicines with many pharmacological activities towards inflammatory symptoms and antioxidation. Chromones are considered as one of the effective components. It is important to find a reasonable method to extract the chromones in S. divaricata. OBJECTIVE: To develop an ultrasonic-assisted extraction (UAE) to extract chromones in Radix Saposhnikoviae and to optimise extraction conditions. METHODOLOGY: Four chromones (prim-O-glucosylcimifugin, cimifugin, 5-O-methylvisammioside and sec-O-glucosylhamaudol) were extracted by the UAE method combined with response surface methodology (RSM). Box-Behnken design (BBD) was applied to evaluate the effects of three independent variables (ethanol concentration, extraction time and extraction temperature) on the chromones yield of Radix Saposhnikoviae. RESULTS: Correlation analysis of the mathematical-regression model indicated that a quadratic polynomial model could be employed to optimise the extraction of chromones by UAE method. The optimal conditions to obtain the highest chromones yield of Radix Saposhnikoviae were a solvent of 75% ethanol, an extraction time of 48 min and an extraction temperature of 67°C. CONCLUSION: Under these optimal conditions, the experimental values agreed closely with the predicted values. The analysis of variance indicated a high goodness of model fit and the success of RSM method for optimising chromones extraction in Radix Saposhnikoviae.