Study On Extraction, Isolation And Purification Of Flavonoid From Gingko

With high medicinal value, the flavonoids have been applied widely as a natural products.There are a lot of flavonoids in ginkgo biloba leaves, how to develop and make full use of ginkgo biloba extract resources has far-reaching significance.In this paper, ultraviolet spectrophotometry and bromimetry were used for the determination of total flavonoid in ginkgo biloba leaves, rutin was select as standard substance. When detecting the content by the ultraviolet spectrophotometry, the detecting wavelength λ was 352 nm, the relationship between absorbency and concentration was A=0.0195c-0.0065 and the linear correlation coefficient R = 0.9991; when using the bromometry, the conditions are found as follows: the dosage of 6mol/L HCl,the dosage of0.1mol/L bromine reagent, the dosage of 10% KI were separetly 3.00 m L,6.00 m L and 3.00 m L,and under that condition, one molecule flavone could react with 5 molecules bromine reagent.In the process of extraction, industrial alcohol reflux method was used to extract flavonoids from ginkgo biloba. Single factor experiment were studied the industrial alcohol volume fraction, the extracting time, the temperature, the ratio of solid to liquid, the microwave time and the microwave power on the influence of extraction amount, and on that basis, through designing the orthogonal experimental, confirmed the best extraction conditions: the extraction temperature was 70℃, the extraction time was 60 min, the ratio of solid to liquid was 1:20, the microwave time was 3min, under this condition, the amount of flavonoids extraction was 84.42 mg/g, the pecking order was: the extraction temperature > the ratio of solid to liquid > the extraction time >the microwave time.The macroporous adsorption resin and polyamide resin were used to isolated and purified flavonoids, by the method of the static and dynamic experiments the process conditions were determined. Through the experiment of the static adsorption kinetics, the adsorption isotherm, the effect of the desorption agent concentration to the desorption rate and the static balance time of desorption to indicate that the balance time of the static adsorption was around 15 minutes, the result of dynamic data fitting conform to the Elovich equation and the correlation coefficient reaches above 0.95, the isothermal adsorption fit for the Freundlich equations and the adsorption process were spontaneous and thermodynamics exothermic, the amount of desorption solvent were 60% and desorption time was 60 minutes;The dynamic experiment including the impact of the concentration and flow rate on the adsorption rate, the impact of desorption agent volume fraction and velocity on the desorption rate, penetrating through experiment and dynamic desorption curve. The optimum operation isgained: the sample concentration were 50μg/m L 、 50μg/m L 、 30μg/m L for the HPD-100 macroporous adsorption resin, FL-2 macroporous adsorption resin and polyamide resin separately,the in-flux rate was 3m L/min for all, the volume fraction of desorption agent was50%, the speed of volume fraction was 3m L/min, the maximum dynamic adsorption capacity were 56.05mg/g、48.69mg/g、22.58mg/g.The seperation and purification flavone extracted from ginkgo biloba also was studied in this paper. The petroleum ether was used to extract the lipid removal from the extract solution,then the HPD-100 macroporous adsorption resin, FL-2 macroporous adsorption resin and polyamide resin were used to separating and purifing the extracting solution.After that the purity and structure of the product has been characterized by uv scanning spectrum, infrared spectrum, high performance liquid chromatogram. The study found that the method have good effect for separating and purifing flavonoids from ginkgo biloba leaves. The total yield was 75.57%.