Study On The Extraction Of Major Flavonoids From Scutellaria Baicalensis Georgi By Microwave Assisted Eutrophic Solvent

In the present study, developing new green solvents is one of the key subjects in Green Chemistry. Deep eutectic solvents (DESs) were used to extract flavonoids (baicalin, wogonoside, baicalein and wogonin) in Radix Scutellariae. It is a rather interesting project that DESs solution as solvent is applied in an efficient microwave-assisted extraction (MAE) of various useful substances from solid samples. The process for purification of flavonoids (baicalin, wogonoside, baicalein and wogonin) in Radix Scutellariae by macroporous absorption resin, and antioxidant activity of crude extracts was studied respectively. The results as follows:1. A HPLC-UV method for determination of baicalin, wogonoside, baicalein and wogonin was developed as follow:The chromatographic column:Luna C18(250mm×4.6mm I.D.5μm); flow rate:1.0mL/min,column temperature:30℃and detection wavelength:276nm; njection volume:5μL;mobile phase:0.10%formic acid (A)-acetonitrile (B). The following gradient elution program was used for separation:0～8min,25～45%(B);8～10min,45～45%(B);10～15min,45～52%(B);15～20min,52～70%(B).2. A range of based DESs with different solvents to choline chloride (ChCl) mixing ratios were used for extraction using MAE extraction methods. Other factors, such as temperature, time, water addition and liquid/soid ratio, were examined systematically using a response surface methodology (RSM). To select the optimal method for extracting flavonoids in Radix Scutellariae and optimize the extraction parameters. The optimum extraction process was as follows: Deep eutectic solvents (DESs):System choline chloride(ChCl):lactic acid ChCl/lactic acid ratio1/2(mol/mol) DESs/water ratio20%Microwave-assisted extraction method:extraction temperature60℃liquid/soid ratio15:1mL/g extraction time12min Under the above optimized conditions, the extraction yield of baicalin, wogonoside, baicalein and wogonin was33.10±1.02mg/g,8.32±0.34mg/g,9.21±0.36mg/g,1.637±0.060mg/g (n=3).3. The optimum process for the purification of flavonoids (baicalin, wogonoside, baicalein and wogonin) in Radix Scutellariae from DESs was obtained firstly, and antioxidant activities the results were as follows: Separation of flavonoids (baicalin, wogonoside, baicalein and wogonin) in Radix Scutellariae by macroporous adsorption resins was studied and the optimum adsorption and desorption parameters on the optimal ME-2resin were obtained, the yield of flavonoids (baicalin,wogonoside,baicalein and wogonin) were84.08%、79.51%、84.96%、81.83%。The antioxidant activities of extracts of SA-3、NAK-9、ME-2、AB-8, accoding to the FRAP and ABTS assay. The extracts of ME-2antioxidant activities with FRAP of0.659mmol Fe(Ⅱ)/g; The extracts of ME-2antioxidant activities with TEAC of0.426mmol/g, respectivelyThe results of this study fully proved the DESs was very applicable for efficient extraction of flavonoids (baicalin, wogonoside, baicalein and wogonin) in Radix Scutellariae due to high the extraction efficiency, high the throughput, low the equipment expenditure and energy consumption. This study provides a scientific basis for the comprehensive development and utilization of Radix Scutellariae.As a potential eco-friendly technology, it is promising for extensive industry applications in the nature product extraction fields.