Study on Extraction and Purification of Total Flavonoids from Lamiophlomis Rotata

Abstract

Lamiophlomis rotata (Duyiwei, DYW) is the dry aboveground part of Lamiophlomis rotata (Benth.) Kudo. The total flavonoids of DYW were extracted by ethanol heating and reflux. With rutin as the reference substance, an ultraviolet spectrophotometry was established to determine the content of total flavonoids of DYW, and the methodology was verified. Taking the yield and content of total flavonoids as the investigation index, the optimum extraction process conditions were optimized by single factor and orthogonal test. Finally, the optimum extraction conditions of total flavonoids of DYW were as follows: solid-liquid ratio 1:6 (g/mL), extraction temperature 60 ℃, extraction time 1.5h and ethanol concentration 85%. Under these conditions, the yield of total flavonoids of DYW could reach 30.24% and the purity could reach 22.78%. Different types of macroporous resins were investigated according to the static adsorption experiment, and AB-8 macroporous resin was selected. Then, the saturated adsorption capacity, pH value of loading solution and concentration of eluting solvent were investigated through the dynamic experiment to determine the method for efficient separation and purification of total flavonoids from ethanol extract. The results show that the optimum process conditions are pH = 5, dynamic saturated adsorption capacity of 3.2 g/g and elution with 80% ethanol. When AB-8 macroporous resin combined with polyamide resin was used to purify the total flavonoids of DYW, the purity was 92.86% and the yield was 69.74%.