Study On The Extraction, Separation And Purification Of Ginkgolide B From Ginkgo Leaves

Ginkgo biloba is a unique woody species in our country, more than70%of theGinkgo resource in the word is located in China, mainly distributed in such provincesas Liaoning, Anhui, Guangxi, Sichuan, Hubei, Hunan, Jiangsu, Zhejiang and so on. Itsleaves, fruits and seeds have found their wide application due to the medicinal value.The chemical composition of ginkgo is relatively complex. It was reported that theremore than180species in ginkgo leaves, the mainly active ingredients are terpenelactone compounds and flavonoids. The terpene lactones compounds, that is ginkgolactone A, B, C, J, M, are the platelet activating factor antagonist, and one ofthem,ginkgo lactone B, is the most active terpene lactones with the strongestpharmaceutical effect and much higher price. More and more attention was attractedin the pharmaceutical and food industries.Ginkgo biloba from different seasons was first researched in the paper,respectively. It was found that the leaves harvested in late October had the highestginkgolide B content. After compared the extraction effect of four different solvents,ethanol was selected as a main extractant to isolate ginkgolide B from Ginkgo bilobaleaves. Orthogonal experimental design was used to determine the optimal isolatingtechnology. The result showed that the best strategy obtained were the ratio of solid toliquid (alcohol amount)1:24g/ml,3times extracting for2.5hours, the ethanolconcentration70%, then, the crude yield was about0.8912%. The significant order ofinfluencing factors was solid/liquid ratio＞extracting times＞ethanol concentration＞extracting time.In preliminary purifing stage, the different types of resin were examined forpurification of ginkgolide B. The adsorption and desorption capacity of ginkgolide Bof four kinds of macroporous resin (alkaline, acidic, anionic, cationic, respectively)were investigated detailly. The results showed that a weak polar resin, AB-8, was thebest one. The best dynamic adsorption conditions were: the adsorbing velocity2BV/h,eluting velocity2BV/h, eluting methanol concentration60%and eluting volume5BV.The purity of ginkgolide B under this condition was77.54%. Liquid chromatography was used for refining Ginkgolide B. Different mobilephases were investigated in order to determine the optimal eluting strategy. Thechromatogram showed that the best peak shape and separation efficiency wereobtained when methanol to water equals to2:8as mobile phase.The results ofanalytical HPLC showed that the purity of Ginkgolide B ws72.70%after the resinpurification, and reached to96.72%after the chromatography used. The final yield ofrefined Ginkgolide B was about0.7297%.