Optimization of the extraction process of phenolic compounds from Strobilanthes crispus L. with the ultrasound-assisted enzymatic−Aqueous two-phase extraction method

The phenolic compounds in the extract of Keji Beling leaves (Strobilanthes crispus L.) are beneficial for human health. It can be an antioxidant, be used as cancer prevention, and be an anti-inflammatory, anti-diabetes, and anti-hyper cholesterol. Several methods of extraction that are commonly used are maceration, soxhlet, reflux, and percolation. However, these methods have several disadvantages such as low selectivity, low yield, and also causing environmental and safety problems. Ultrasound-Assisted Enzymatic – Aqueous Two-Phase Extraction (UAE-ATPE) is one of the green extraction methods used to extract, which could minimize the various shortcomings of the conventional method. In this study, the Aqueous Two-Phase System (ATPS) used, which is a two-phase solvent between salt and organic solvent, will increase the purity of the TPC (Total Phenolic Content) extract. In this research, cellulase enzyme with an enzyme concentration of 70 mg/gr of leaves powder, the 0.0885 mm size of leaf powder with a ratio of 1:20 w/v, and a solution consisting of ethanol-ammonium sulfate with a ratio of 33% and 14% in the total solution were used to determine the optimal condition that affects the TPC yield. The extraction was carried out for 3 hours using a sonicator with a frequency of 20 Hz and temperature variations of 30°C, 40°C , 50°C, and 60°C. The result shows that the TPC levels increase as the extraction time and temperature increase. However, at a certain temperature and time, the TPC levels tend to be constant. This research shows that the optimum TPC level in the UAE-ATPE extraction process was obtained at a temperature of 50°C with a time of 140 minutes, which was able to produce a TPC level of 4.21 mgGAE/g leaves.