Study On Hydrolysis Of Ginkgo Flavone By Strong Acidic Ion Exchange Resin And Its Purification

Ginkgo flavonoids are the most important component in the pharmacologically active constituents of Ginkgo biloba leaves,and ginkgo flavonoids mainly exist in the form of flavonoid glycosides.Studies have shown that the flavonoids aglycones,the hydrolysate of flavonoid glycosides,has far more physiological activity than that of flavonoid glycosides.At present,the main hydrolysis methods,acid hydrolysis method and enzymatic hydrolysis method,have some deficiencies.Therefore,this paper chooses to study the hydrolysis of ginkgo flavonoids by solid acid,and the flavonoids aglycones obtained by hydrolysis was separated and purified.Firstly,two strong acidic ion exchange resins,732 and D61,were selected as the solid acid to catalyze the reaction,and the optimum conditions for the hydrolysis of ginkgo flavonoids by two strong acidic ion exchange resins were obtained by single factor experiments and orthogonal experiments,and the difference of recyclability and adsorption performance between the two resins catalyzed the hydrolysis of ginkgo flavonoids were compared.Secondly,the reaction kinetics of ginkgo flavonoids hydrolysis were studied by D61 resin catalyzed hydrolysis of ginkgo flavonoids.The activation energy and kinetic constant of the hydrolysis reaction were obtained.Finally,three kinds of macroporous resins were selected to purify the flavonoids aglycones,and the suitable purification process conditions were obtained by dynamic adsorption experiments and single factor experiments.The main research contents and results of this paper are as follows:1.The optimum conditions for the hydrolysis of ginkgo flavonoids by 732 and D61 strong acid ion exchange resins were obtained by single factor experiments and orthogonal experiments.The optimum conditions for the hydrolysis of ginkgo flavonoids by 732 resin were as follows:reaction time 8 h,reaction temperature 110?,ratio of the amount of catalyst to liquid 0.020 g-mL'1,ratio of material to liquid 0.8 mg-mL'1,and the hydrolysis rate of ginkgo flavonoids was 96.7%under these conditions;The optimum conditions for the hydrolysis of ginkgo flavonoids by D61 resin were as follows:reaction time 8 h,reaction temperature 100?,ratio of the amount of catalyst to liquid 0.010 g·ML-1,ratio of material to liquid 1.0 mg·mL-1,and the hydrolysis rate of ginkgo flavonoids was 92.1%under these conditions..2.The kinetic parameters of hydrolysis of ginkgo flavonoids by D61 resin were obtained by a simplified model of hydrolysis of ginkgo flavonoids,it is concluded that the process of hydrolysis of ginkgo biloba leaves follows the first-order reaction law,and the activation energy of the reaction and the reaction kinetic constant are obtained,which fit well with the calculated results.3.Flavonoids aglycones products were purified by macroporous resin.The effect of adsorption and desorption of flavonoids aglycones by AB-8,D101 and D140 macroporous resin and polyamide resin is studied by static adsorption,and it is found that D140 resin is the most suitable for purifying flavonoids aglycones.By dynamic adsorption experiments and single factor experiments,the optimum process conditions for the purification of ginkgo flavonoids aglycones by D140 resin were obtained,including the loading concentration 1 mg-mL'1,the weight of D140 resin 2 g,the loading volume 20 mL,the loading flow rate 1 mL·min-1,and 25 mL 30%ethanol and 30 mL 70%ethanol used as the two gradient elution solvents,respectively.Under the conditions,the content of flavonoids aglycones in the product can reach 45.54%,and the yield is 80.87%.?Through the above research,the relevant research results can provide theoretical guidance and technical support for the industrial design and operation of the preparation of ginkgo flavonoids aglycones.