Study On The Extraction And Purification Process Of Ursolic Acid From Eriobotrya Japonica Leaves

Eriobotrya japonica leaves is a kind of Chinese traditional herb with widespread application value in medicinal field,which is usually applied for the treatment of ronchitis, lung heat. Ursolic acid, as the main active ingredient in eriobotrya japonica leaves, is a kind of pentacyclic triterpe compound with high content in eriobotrya japonica leaves. Ursolic acid is widely applied in medicine and functional foods. Ursolic acid is known to have a wide variety of pharmacological properties, including anticancer, antiviral, antioxidant properties, and therefore ursolic acid has wide application prospect.The ursolic acid was extracted from eriobotrya japonica leaves by using ethanol refluxing. Extraction parameters were optimized by the method of single factor. Content of ursolic acid was detected by HPLC. With the rate gained, the optimized process parameters were acquired as follows: alcohol-water ratio 95%, temperature 85℃, treatment time 2.5 h, and liquid-solid ratio 10:1 (mL:g). On the basis of single factor experiments, the extraction process parameters was optimized by Box-Behnken design and surface response method, and then multiple regression equation with predictive analysis was established. The results showed that the order of the effect of factors on the rate turned out to be:extraction time>liquid-solid ratio>extraction temperature. Optimized extraction process parameters were as follows:alcohol-water ratio 95%, temperature 85℃, treatment time 2.8h, and liquid-solid ratio 15:1 (mL:g), and under these conditions the extraction rate can reach 93.3%, the extraction volume 8.78 g/kg.We applied surface molecular imprinting technique by making silica gel as the carrier, ursolic acid as template molecular, and methylacrylic acid as functional monomer to prepare the molecular imprinting polymers possessing selectivity of adsorption for ursolic acid by cross-linking polymerization. The molecular imprinting polymers was characterized by IR and SEM. The results showed that the surface prepared by boltting ursolic acid molecules can be imprinted with polymer molecules with the goal of mutual recognition ursolic acid in the "hole".The static adsorption test proves its high selectivity and high affinity for ursolic acid and therefore the molecular imprinting polymers can be used to separate and rich ursolic acid.The purification of ursolic acid firstly used acid and alkali method taking advantage of the different solubility in solution of different pH value, the result was that making the solution pH=11,then pH=4. aqueous solution with pH=4 as the same volume was added. Ursolic acid was obtained with the purity of 32.3%. Then we used AB-8 macroporous resin as adsorption to separate ursolic acid and the results are as follows:adsorption solvent alcohol-water ratio 60%, desorption solvent alcohol-water ratio 90%, adsorption time 2.5 h. Ursolic acid was obtained with the purity of 54.6%. Molecular imprinted polymer was used as SPE filler and the purity of ursolic acid reached 95.8%. The research of extraction and purification in this paper, makes a reference for comprehensive utilization of Eriobotrya japonica leaves and extraction, enrichment, purification of ursolic acid in large scale production.