Orthogonal test design for optimization of the isolation and purification of total favonoids from Artemisia frigida Willd using macroporous resin chromatography

In the present study, the authors aimed to use an orthogonal test design to optimize conditions for isolating and purifying total flavonoids from Artemisia frigida Willd (A. frigida) using macroporous resins. An orthogonal L9(3)4 test design was applied to select the optimum isolation and purification parameters, including the volume of sample solution, flow rate of adsorption and eluent concentration and volume. The efficiency of isolation and purification was evaluated by measuring the concentration of total flavonoids with an ultraviolet (UV) spectrophotometer. The qualitative analysis of the extracted flavonoids was carried out using infrared absorption spectroscopy (IR) and nuclear magnetic resonance (NMR). The crude extract from A. frigida was successfully isolated and purified by macroporous resin chromatography under the optimum conditions (the volume of sample solution, 40 mL; the flow rate of adsorption, 3.0 mL/min; the eluent concentration, 90% ethanol; the eluent volume, 40 mL). The positive reactions to Molish and HCl~Mg tests suggested that the extracted compounds were flavonoids. Furthermore, FTIR and NMR measurements also confirmed the presence of flavonoids in the extracts. The D101 macroporous resin is the most effective one for large-scale isolation and purification of flavonoids from A. frigida, and it meets industrial needs. Key words: Artemisia frigida Willd, total flavonoids, orthogonal experiment design, ultraviolet (UV) spectrophotometer, macroporous resin.