Extractian And Purification Of Flavonoids In Silybum Marianum

Silybum marianum is a annual or biennial herb of the genus Silybum in the composite family.Except fonding the cool and dry environment,it is resilient and lax to water and edaphic requirement such as Saline alkali soil,wasteland and farm.Silybum marianum has been introduced from the Europe in the early 70 ’s and planted as the liver medicinal plant that the flavonoids of Silybum marianum is the active ingredient.The flavonoids and complex have the high biological activities and the good curative effect on liver cirrhosis,fatty liver,alcoholic hepatitis and metabolic toxic hepatitis.At present the method using 2,4-dinitrophenylhydrazine is adopted to evaluate the extraction of the flavonoids from Silybum marianum.This experiment regards silybin as contrast caliber and determines content of total flavonoids in extract by UV spectrophotometry.In order to more evaluate the extraction effects which are affected by different solvent and different methods of extraction,this experiment also determines content of the silybin by HPLC.The results show that these two methods are simple,accurate,reproducible,and can be used for the determination of the content of total flavonoids and silibinin.In this experiment,the examine of extracting the flavonoids uses four methods of soxhlet extraction,accelerated solvent extraction,alkali extraction and acid precipitation,and extraction tank circulation.After screening the orthogonal experiment,the better extraction technology are established as a basis for improvement.Silibinin is the component with the highest activity and content of silybum marianum,as the standard substance in the determination of the content of flavonoids.We can get two compounds with the following methods.Firstly,using AB-8 macroporous adsorption resin column chromatography.Secondly,three different concentrations ethanol solution were used to eluent.Then,combined components and separated with thesilica gel column chromatography,ODS column chromatography and HPLC.Finally,the Chemical structure of two compounds can be identificated by analysising the physico-chemical properties and their spectral datas.Consider with the factors of the yield,safety,price and conditions,the optimal method refining silibinin was obtained by the traditional methods.The optimum conditions of the recrystallization of silibinin is as the following.First,10.0g milk thistle were refluxed with ethanol,standed and filtered,then obtained crude product.1.0g crude product were refluxed with ethanol refluxing,standed and filtered,then obtained pure product,weighted 0.46g.The yield of crude product is 17.2%,and the yield of pure produc yield is 46%.