Study On Extraction And Purification Of Flavonoids From Mulberry Leaves

Mulberry leaves are traditional Chinese medicine,also called iron fan,and it is dry leaf of Moraceae plant,which has the effects of dispelling wind heat,improving eyesight,clearing liver,lowering blood pressure,reducing blood fat,reducing blood sugar,anti-oxidation,elimination of free radicals and so on.Mulberry leaves contain polysaccharides,alkaloids,flavonoids,amino acids,coumarins,volatile oils and other active ingredients.In this paper,the optimal extraction conditions of flavonoids from mulberry leaves,the separation of flavonoids from mulberry leaves via high-speed counter-current chromatography and structure identification of products were studied.The flavonoids from mulberry leaves were extracted by ethanol extraction and ultrasonic extraction.To determine the best technology of ethanol extraction and ultrasonic extraction conditions.Comparing the two extraction methods,we found that ultrasonic extraction is better than the ethanol extraction on the extraction time and extraction yield finally,the optimum conditions for ultrasonic extraction were: ethanol mass percentage 60%,liquid-solid ratio is 50:1(mL/g),ultrasonic time 20 min,temperature 60?,ultrasonic power is 325 W,and extraction rate is 6.13%.High-speed counter-current chromatography was used to separate and purify the flavonoids from the mulberry leaves for the first time.The effects of the molecular structure of flavonoids and the polar parameters of the solvent system on the retention rate of the fixed phase and the purity of the product were analyzed theoretically.By comparing the effects of different solvent systems and mobile phase flow rates on the retention of stationary phase,the optimal separation conditions for high-speed counter-current chromatography were determined at 800 rpm,stationary phase working flow rate of 30mL/min,mobile phase working flow rate was 5mL/min,and detection wavelength was 257 nm.V(ethyl acetate):V(n-butanol): V(water)=4:1:5 was selected as the optimum solvent system.The finally obtained separated products were concentrated and detected by high performance liquid chromatography.The detection conditions were as follows: mobile phase was V(chromatography methanol): V(0.5% phosphoric acid aqueous solution)=50:50 gradient elution,flow rate was 1mL/min,column temperature was 30?,detection wavelength was257 nm,injection volume was 30?L.The content of flavonoids in the purified solution was93.8%,and the RSD value was 1.8%(n=4).The results greatly improved the purity of activecomponents from mulberry leaves and provided a basis for the separation and purification of active components from mulberry leaves.