Burdock Leaves Chlorogenic Acid Extraction And Purification

Arctium lappa L. is a member of the composite family,and is a kind of 2-year borne giant herb. Arctium lappa L. contains many bioactive substances and secondary metabolites,it hardly infected with pathogen. Arctium lappa L. is of specific and important physiological action and pharmacological function.It is a Chinese herb,and also a kind of vegetable.Chlorogenic acid is one of the main effective components in the leaves of Arctium lappa L..It has the functions of antagonizing pathogenic micro-organism,antivirus,declining fever, hoisting leucocyte, protecting liver, adjusting immune function, antagonizing tumour, lowering blood-lipid, scavenging oxygen free radicals and so on. So it has economic signification that extraction and purification of chlorogenic acid from abundant leaves of Arctium lappa L.In this paper, extraction and separation of chlorogenic acid were reviewed. Alcohol-extractive and then resin adsorption method was further studied. Through studying the effects of extractive solution, extractive time, ratio of solvent to material, extractive temperature and pH value of the solution, the optimum condition are determined. Resin adsorption method was used to enrich and isolation chlorogenic acid from the extraction solution. By comparing five different macroporous resins, NKA-9 was selected to separate chlorogenic acid. In order to find out the optimum conditions, the factors of effecting adsorption and elution were also researched, such as pH value , speed of adsorption, effluent speed and eluting agent. Results showed:1. Extraction process of Chlorogenic acidThe process on extraction and separation of chlorogenic acid from Arctium lappa L. leaves was studied in the paper. The max absorption wave length of chlorogenic acid was determined by ultraviolet spectrophotometer, it showed that its max absorption wave length was 328nm. Main factors influencing the extraction of chlorogenic acid from the leaves of Arctium lappa L. were studied by single factor and orthogonal experiments as well as multiple analysis. The results showed that the determination method of ultraviolet spectrophotometer was acute, precise and exact. The optimized conditions for the extraction of chlorogenic acid in leaves of Arctium lappa L. were obtained: the leaves of Arctium lappa L. were extracted by 60% ethanol at 70℃for 3h with a ratio(material to solvent)of 1:14. In this condition, the final yield of chlorogenic acid is 1.82%.2. Isolation & purification process of chlorogenic acidThe optimum condition and parameters of purifying chlorogenic acid from Arctium lappa L. leaves with macroporous resin were studied. Absorption and elution capacities of five resins for chlorogenic acid were determined and compared, the results showed that NKA-9 resin was better than the other resins . The adsorption parameters are: the content of chlorogenic acid is 0.259mg per mL adsorption solution, the acidity of adsorption solution (in terms of pH) is 4, the adsorption velocity of flow is 4BV/h, the eluent is 50% ethanol, the eluting speed is 2BV/h and the acidity of eluention solution (in terms of pH) is 4. In the optimal adsorption condition, content of chlorogenic acid is above 26.3%, the gained rate of chlorogenic acid inexcess of 72.5%.3. A new practical method to isolate chlorogenic acid have been developed and the cost of the production has been considerably reduced.