Optimization of Ultrasound Assisted Extraction of Phenolic Compounds and Anthocyanins from Perilla Leaves Using Response Surface Methodology

Ultrasound assisted extraction (UAE) was used to extract phenolic compounds and anthocyanins from perilla leaves. Response surface methodology (RSM) was used to optimize the extraction conditions. The optimal conditions were as follows: ethanol concentration of 76.58%, liquid-to-solid ratio of 22.15:1, extraction temperature of 52.75 degrees C and extraction time of 53.84 min. Under these optimal conditions, total phenolic content (TPC) and the total anthocyanins content (TAC) were 63.11 mg gallic acid equivalent (GAE)/g dry weight (DW) and 6.44 mg cyanidin-3-glucoside equivalent (CGE)/g DW, respectively. The experimental data are consistent with the predicted values, confirming that the model was valid for optimization of the extraction conditions. In addition, perilla extract was purified using XAD-7 resin. The antioxidant activity of purified extract was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-ethyl-benzo-thiazoline-6-sulphonate (ABTS) methods (50% inhibition values of 19.88 mu g/mL by DPPH and 81.75 mu g/mL by ABTS). The results indicated that purified extract exhibited potent antioxidant capacity.