A modified ultrasound-assisted extraction (MUAE) method and an HPLC technique were developed to identify and quantify simultaneously the amount of oleanolic acid (OA) and ursolic acid (UA) in Scutellaria barbata D. Don. The optimal conditions for MUAE were observed when the particle size was 0.2-0.5mm, the duty cycle was 75%, the extraction temperature was 55 degrees C, the ratio of solvent to raw material was 12.0:1 (mL:g), the ethanol concentration was 60%, and the extraction time was 25min. Compared to the traditional extraction method, MUAE reduced the extraction time, extraction temperature, and solvent consumption and achieved superior yields of OA and UA. Furthermore, the combined MUAE-HPLC method was successfully applied for the first time to investigate and compare the amounts of OA and UA in samples obtained from different geographical regions.
Chemical Engineering Communications, v.201 n.4, pp.482-500