Extraction Of Bioactive Components From Cardamine

As a natural super-selenium-rich plant,Cardamine is rich in a variety of beneficial bioactive ingredients.The in-depth study of its beneficial components will contribute to improve its bioavailability.Traditional extraction of bioactive components from plants often uses organic solvents,which causes environmental pollution and unsustainable problems,so it is necessary to explore a greener extraction method.As a new green solvent,deep eutectic solvent（DES）has the advantages of easy degradation,abundant sources,simple preparation and sustainability.In this paper,DES was used as the extraction solvent to extract selenoprotein,seleno-amino acids and flavonoids from Cardamine,and their contents were analyzed by different detection methods.The specific research contents are as follows:（1）Twelve kinds of DES were prepared with choline chloride and betaine as hydrogen bond acceptors and citric acid,sorbitol,ethylene glycol,glycerin,glucose and urea as hydrogen bond donors,respectively.It was found that DES prepared with choline chloride and urea（1:4）at a preparation temperature of 60°C and water content of 50%had the best extraction effect on selenoprotein.Single factor experiment and response surface design was used to optimize the extraction conditions.The results showed that the optimum extraction conditions of selenium-rich protein from Cardamine were as follows:temperature 47℃,liquid-solid ratio 54 m L/g and time 21min.Under these conditions,the extraction rate of selenoprotein from Cardamine was10.76%.Selenoprotein in the extract was precipitated by ethanol quadruple volume precipitation method,the precipitation rate was 85.32%,and the purity of dried crude protein was 61.47%.（2）Free seleno-amino acids in Cardamine extracted by ultrasonic assisted DES were analyzed by HPLC with fluorescence method.The results showed that the free seleno-amino acids in Cardamine were mainly Se-（methyl）-selenocysteine（Se Me Cys）and selenocystine（Se Cys₂）.The extraction effect of DES prepared by choline chloride and ethylene glycol（1:2）was the best when the water content was 30%.At the same time,the extraction conditions optimized by single factor experiment and response surface design.The results showed that the optimal extraction conditions of Se Cys₂ and Se Me Cys in Cardamine were as follows:liquid-solid ratio 50 m L/g,temperature 40℃,and time 45 min.Under the optimum conditions,the content of Se Cys₂ is 356μg/g,and the content of Se Me Cys is 147μg/g.（3）The contents of flavonoids in DES extract were quantitatively analyzed by UV-Vis spectrophotometry.The results showed that choline chloride and urea（1:2）had the best extraction rate of flavonoids from Cardamine at the preparation temperature of40℃,the water content of 50%.Single factor experiment and response surface design was used to optimize the extraction conditions.The results showed that the best extraction conditions of flavonoids from Cardamine were as follows:extraction time25 min,extraction temperature 52℃and liquid-solid ratio 25 m L/g.Under these conditions,the extraction rate of flavonoids was 1.33%.The selenium content in the extract was determined by fluorescence spectrophotometry under the optimal extraction conditions,and it was found that the total selenium content in the extract was 642μg/g,the extraction rate was 48.34%,the organic selenium content was 634μg/g and the extraction rate was 72.62%.