Optimization of Microwave-assisted Extraction of Ursolic Acid from Ligustrum lucidum Ait Using Response Surface Methodology

The processing for microwave-assisted extraction of ursolic acid(UA)from Ligustrum lucidum Ait were optimized. Based on the results of single-factor tests,four factors including ethanol concentration(V/V),microwave power,solid-to-liquid ratio and extraction time were identified as main variables that affected extraction efficiency. The extraction efficiency of ursolic acid as the response was analyzed by response surface methodology. The results showed that optimum extraction conditions were as follows:Ethanol concentration of 88%,microwave power of 480 W,solid-to-liquid ratio of 1:23 g/mL,and extraction time of 166 s. Under these conditions,the yield of ursolic acid was(4.653±0.087) mg/g,which was 99.53% of the predicted value.