Abstract: This work aimed to establish an efficient method for the preparation of highly pure chlorogenic acid from Lonicera confusa. Two extraction methods,conventional water extraction and alkaline water extraction at ambient temperature,were optimized by orthogonal experimental design.The purification processes using D101 macroporous resin,ethyl acetate liquid-liquid extraction,solvent crystallization were also optimized.Maximum extraction yield of 7.2% chlorogenic acid was achieved by using alkaline water at pH=10 as solvent,extraction time of 1 h,and solid-to-liquid ratio of 1:30.As to the eluent of D101 macroporous resin,eluate of best purity was achieved by using 10% aqueous ethanol,and eluate of highest chlorogenic acid content was achieved by using 30% aqueous ethanol.It was optimized to perform liquidliquid extraction for 5 times.Ethyl acetate saturated with water was the best solvent for crystallization.With the developed extraction and purification methods,chlorogenic acid at the purity of 98.7% with a yield of 1.84% was achieved.The purity and yield were better than those recorded in other reported methods.Moreover,the extraction was performed at ambient temperature in a short period of time and significantly reduced the energy consumption.Hence,it was suitable for large'scale industrial production.

Key words: chlorogenic acid, Lonicera confusa, alkaline water extraction, D101 macroporous resin, crystallization