Optimizing the flash extraction process for total flavonoids from Edgeworthia gardneri (Wall) Meissn and antioxidant activity of the extracts

Abstract

Abstract In order to efficiently extract natural medicines, response surface methodology (RSM)were used for the modeling and optimization of flash extraction of total flavonoids to determine the antioxidant activity of the extracts obtained from Edgeworthia gardneri (Wall). For the optimal combination of the comprehensive yield of total flavonoids (Y), the Box-Behnken design (BBD) was used to improve extract voltage (X1), extraction time (X2), ethanol concentration (X3), and liquid-solid ratio (X4). Based on the results of single factor test, the amount of total flavonoids extracted from Edgeworthia gardneri (Wall) Meissn was used as the evaluation index. The Box-Behnken experimental design was used to optimize the flash extraction process and to investigate the antioxidant activity in vitro. The results showed that the optimal extraction conditions were as follows: extraction voltage 150 V, flash extraction time 100 s, ethanol volume fraction 70%, solid-liquid ratio 1:30 mL/g, and total flavonoids extraction amount of 18.91 (mg/g). The total flavonoids of Edgeworthia gardneri (Wall) Meissn had significant scavenging ability against 2,2-diphenyl-1-picrylhydrazyl (DPPH), O2- and OH free radicals, and had good antioxidant activity. Furthermore, the HPLC separation conditions of total flavonoids of Edgeworthia gardneri (Wall) were explored. Under the set HPLC conditions (Hanbon benatach C18 250 mm × 4.6 mm, 5 μm, A: acetonitrile-B: 0.2% formic acid aqueous solution, 0→10→50→65→85 min, 5%→10%→30%→45%→90% A gradient elution, 1 mL/min, 314 nm, Column temperature: 25 ℃), the main components of total flavonoids of Edgeworthia gardneri (Wall) could achieve a good separation, which provide the separation conditions and basis for the identification of total flavonoids from Edgeworthia gardneri (Wall) Meissn.