Abstract:

This study investigated the ethanol extraction and the purification using macroporous adsorption resin of ursolic acid from hawthorn fruits. An orthogonal array design involving 16 experiments of four crucial factors at four levels was employed to maximize the ethanol extraction. The optimal macroporous adsorption resin and solvent for purifying ursolic acid were determined and the dynamic adsorption and desorption of ursolic acid on macroporous adsorption resin AB-8 were investigated. The optimum extraction conditions of ursolic acid were as follows: using 90% ethanol as the extractant and a ratio of solid to liquid of 1:10, extraction at 80 ℃ for 2.5 h, and the extraction yield of ursolic acid was 1.07% under these conditions. The optimum purification conditions with macroporous adsorption resin AB-8 were as follows: ursolic acid concentration 3.01 –4.01 mg/ml and eluent pH 10.0 for a stepwise elution with water and different concentrations of ethanol solution at a flow rate of 1.5 ml/min. A purity of 97.0% and a recovery of 98.1% were achieved under the optimized purification conditions. An ursolic acid product with high purity and yield can be obtained by this extraction and purification process and therefore it is a promising approach for the industrialized production of ursolic acid.

Key words: hawthorn, separation and purification, ursolic acid, macroporous adsorption resin