Study on Isolation and Purification of Ginkgolide A from Ginkgo Leaves

Objective:To establish a simple method of extraction,isolation and purification for ginkgolideA from ginkgo leaves.Methods:The ginkgolideA in ginkgo leaves was extracted,isolated and purified by extracting with alcohol-water solution and ethyl acetate,by macroporous resin′s adsorption and elution,as well as by crystallization and recrystallization.The optimum conditions of the process were studied by taking the yield and purity of ginkgolideA as index.Results:The optimum conditions of the process were confirmed as follows:the pH value of ethanol extract from ginkgo leaves was adjusted to 3 before extraction with ethyl acetate;the pH value of ethyl acetate extract was adjusted to 3 and then NM100 macroporous resin was used to adsorb the ethyl acetate extract,with the flow rate of 1 mL ·min-1;The column was eluted with 30% and 50% ethanol respectively,and then the 50% ethanol eluant was collected and concentrated;The 50% ethanol eluant was crystallized at 4 ℃,and then the macrocrystal was recrystallized in ethanol-water system with the ratio of 2:1.The purity of the ginkgolide A prepared in this process was above 99%,with the yield of 60%.Conclusion:The process is stable and feasible.It can be applied to industrial production.