Isolation And Purification Of Alkaloids From Lotus Leaves And Flavonoids From Euonymus Alatus By High-speed Countercurrent Chromatography

Obesity and diabetes have become a public health problem all over the world.Traditional Chinese medicine is the treasure of the Chinese nation.It has a long history of drug use.According to the related literature,lotus leaves contain a large amount of alkaloids,which have good weight loss effect.There are many flavonoids in Euonymus alatus,which has a certain hypoglycemic effect.However,it is hard in the preparative separation of target compounds from traditional Chinese medicine,which has many complex compounds.High-speed countercurrent chromatography,as a liquid-liquid partition chromatography,without the use of solid-support matrix,could eliminate the irreversible absorption,denaturation,deactivation and ensure the high recovery rate of the samples,also have the advantage of large preparation.It has been widely used in the separation and purification of natural products.While in the separation of high-speed countercurrent chromatography,the selection of solvent system is very important.Ionic liquids have received extensive attention for their unique properties of negligible vapor pressure,high thermal stability,tunable viscosity,unique solubility.They are considered as a possible solvent system modifier in high-speed countercurrent chromatography,because they can combine with water and weak or non-polar organic solvent to form a two-phase system and could significantly influence the partition of compounds in solvent system,result in a shorter analytical time and better separation.In this paper,high-speed countercurrent chromatography was applied to separate alkaloids from lotus leaves and flavonoids from Euonymus alatus.The main research results are as follows:1.An effective high-speed countercurrent chromatography method for separating alkaloids from lotus leaves was successfully established by using ionic liquids as the modifier of the two-phase solvent system.Adding a small amount of ionic liquids significantly shortens the separation time and improves the separation efficiency.The conditions of ionic-liquid modified high-speed countercurrent chromatography including solvent systems,types and content of added ionic liquids,and ionic liquids posttreatment were investigated.With a solvent system consisting of petroleum ether-ethyl acetate-methanol-water-[BMIM][BF4](1:5:1:5:0.15,v/v/v/v/v),four alkaloids pronuciferine(1.7 mg),N-nornuciferine(4.3 mg),nuciferine(3.1 mg),and roemerine(2.1 mg)were obtained with the purities of 90.53,92.25,99.86,and 98.63%,respectively,from 100 mg crude extract of lotus leaves.2.A high-speed countercurrent chromatography method for separating flavonoids from crude extracts of Euonymus alatus was established.The effects of several solvent systems on the separation efficiency of target compounds in the extracts of Euonymus alatus were studied.Finally,with the solvent system of hexane-ethyl acetate-methanol water(3:5:3:5,v/v),an active target compound was obtained with the purity of 96.80%,and other target compounds were also enriched during the separation process.