Therefore, the solid-liquid ratio of 1:20 was chosen for further optimization studies.Figure selleck kinase inhibitor 2Effect of extraction solvent on TPC and chlorogenic acid yield (solid-liquid ratio, 1:15; extraction time, 30min; number of extractions, 1; n = 5).2.3. Effect of Ultrasonic Time on Yield of TPC and Chlorogenic AcidIn order to obtain the maximum yield of TPC and chlorogenic acid from the root of I. helenium, ultrasound-assisted extractions were performed at five extraction time (20, 30, 40, 50 and 60min). The effect of different extraction time on yield of TPC and chlorogenic acid is shown in Figure 3. It was reported that long period of extraction time favors the phenolic compounds production [20]. Likewise, at constant ethanol concentration and solid-liquid ratio, increasing the extraction time significantly increased the yield at the initial stage.

But further increased in the ultrasonic time did not show any increase in the total phenolic content when the extraction was more than 40min. Accordingly, 40min was chosen as the extraction time in succeeding experiments.Figure 3Effect of solid-liquid ratio on TPC and chlorogenic acid yield (ethanol concentration, 25%; extraction time, 30min; number of extractions, 1; n = 5).2.4. Effect of Number of Extractions on Yield of TPC and Chlorogenic AcidIn order to evaluate the number of extractions on yield of TPC and chlorogenic acid, four different numbers of extractions were applied to the extraction experiments, respectively.

It can be seen from Figure 4 that the yield of TPC and chlorogenic acid was first increased with increasing extraction times, and a relatively high yield of TPC and chlorogenic acid was achieved when the samples were extracted for 3 times. Figure 4Effect of ultrasonic time on TPC and chlorogenic acid yield (ethanol concentration, 25%; solid-liquid ratio, 1:20; number of extractions, 1; n = 5).2.5. Orthogonal Design Experiment An orthogonal array of four factors and three levels was constructed to optimize UAE conditions. The experimental design and data analysis are shown in Table 1. The Km (m = 1�C3) values are the averages of TPC or chlorogenic acid of every factor at each level. R value is the range of K value. According to the R value, it can be observed that there were great differences between each factor.

The number of extractions Carfilzomib was found to be the most important factor, afterward followed by ethanol concentration, ultrasonic time, and solid-liquid ratio. Therefore the maximum yield of TPC and chlorogenic acid was obtained when the conditions were C2A3D2B2, namely, number of extractions 2 times, 30% ethanol as the solvent, ultrasonic time of 40min, and solid-liquid ratio of 1:20, respectively. Through confirmatory test, the yield of TPC and chlorogenic acid was 6.13 �� 0.58 and 1.32 �� 0.17mg/g, respectively.