Ultrasound-assisted extraction of oleanolic acid and ursolic acid from Ligustrum lucidum Ait

Oleanolic acid and ursolic acid are the main bioactive compounds in fruit of Ligustrum lucidum Ait, which possess anti-inflammatory, antioxidative, antiprotozoal, antimutagenic and anticancer properties. In this study, the ultrasound-assisted extraction of oleanolic acid and ursolic acid from L. lucidum Ait was investigated with HPLC-photodiode array detection. Effects of several experimental parameters, such as type and concentration of extraction solvent, ratio of liquid to material, extraction temperature and extraction time, on extraction efficiencies of oleanolic acid and ursolic acid from L. lucidum were evaluated. The influence of experimental parameters on extraction efficiency of ursolic acid was more significant than that of oleanolic acid. The optimal extraction conditions were 95% ethanol, the ratio of material to liquid at 1:20, and extraction for 10 min at 40 °C under ultrasonic irradiation. Under the optimal conditions, the yields of oleanolic acid and ursolic acid were 6.3 ± 0.25 and 9.8 ± 0.30 mg/g, respectively. The results indicated that the ultrasound-assisted extraction is a very useful method for the extraction of oleanolic acid and ursolic acid from L. lucidum.