Abstract: In order to achieve maximum yield of volatile oil from Fructus Amomi Rotundu, the conditions for microwave-assisted extraction were optimized by response surface methodology. In single factor experiments, ethyl acetate was found to be the best solvent for the extraction of volatile oil, and extraction parameters such as solvent-to-material ratio, extraction time and microwave power were identified as main factors affecting oil yield. On the basis of the results, a 15-run Box-Behnken experimental design involving the three main affecting factors (extraction parameters) at thee levels was used to establish a quadratic regression model for oil yield, and the model was analyzed by response surface analysis to find out the optimal levels of the three extraction parameters. The results showed that solvent-to-material ratio of 10:1 (mL/g), extraction time of 153 s and microwave power of 322 W were obtained as the optimal conditions. Under the optimal conditions, the experimental extraction yield was 2.67%, which was close to the predicted one of 2.64%. Thus, this model had good prediction ability.

Key words: microwave-assisted extraction, Fructus Amomi Rotundus, volatile oil, response surface methodology