Chemical Composition And Bioavailability Of Polyphenols And Saponins From Astragalus And Hedwig

Astragali radix(AR)and Hedysari radix(HR)are the two most widely used Chinese medicinal herbs and also medicine and food homology.They can be used as tonics,antioxidants,immune stimulants,etc.,and have broad clinical application prospects with antioxidant,hypoglycemic,anti-inflammatory and antiviral functions.According to the 2015 Pharmacopoeia of the People’s Republic of China,AR and HR have the same effect.In Traditional Chinese Medicine,AR and HR were undistinguished in medication.Non-extractable polyphenols(NEPP)are the non-extractable fraction in aqueous and organic solvent or bound to macromolecules such as dietary fiber,and also the main component of dietary polyphenols.Extractable polyphenolics(EPP)are generally researched more hence NEPP have been ignored.In the present study,response surface methodology(RSM)was used for optimizing conditions of flavonoids and triterpene saponins extraction and separation.The EPP and NEPP of AR and HR were characterized by HPLC profiling and chemometrics.Furthermore,DPPH radical scavenging activity(DPPH assay),ABTS radical scavenging activity(ABTS assay)and ferric-reducing antioxidant power(FRAP assay)of EPP and NEPP in AR and HR were investigated.In addition,an in vitro digestion of AR and HR was performed to evaluate the bioaccessibility of polyphenols and systematic comparison of the polyphenol flavonoid monomers before and after digestion of EPP and NEPP in AR and HR.The main results are showed as following:1.Box-Behnken design method(BBD),ultrasonic assisted aqueous two-phase extraction(UAATPE)were used to optimize the optimal extraction conditions of flavonoids and triterpene saponins extraction and separation,liquid-to-solid ratio of 45 mL/g,ultrasonic power 415 W and extraction time of 36 minutes to maximize the total flavonoid content(TF)(4.86 ± 0.05 mg RE/g DW)and total saponins content(TS)(45.74±1.44 mg AE/g DW),while the corresponding variables with a maximum total polyphenol content(TP)(2.43 to 0.02 mg GAE/g DW)are 40 mL/g,412 W of ultrasonic power and extraction time of 37 minutes,and the separation rate is also the highest,which is fully illustrated by the verification test.HR residue after UAATPE by the electro-mirror scan results compared to the same particle size under the raw materials,ultrasonic auxiliary water,and ultrasonic auxiliary ethanol lift shows that the tissue was seriously damaged,indicating that the extracted active ingredients are more abundant.The HPLC analysis also showed that,under the best conditions,the top phase of the HR extract detected a concentration of ten representative flavonoid monomer components,and in the bottom phase of the extract detected two main saponins,namely Astragaloside Ⅳ and Astragaloside Ⅰ.In addition,compared with ultrasonic-assisted water extraction or ultrasonic-assisted ethanol extraction,UAATPE is used to extract and separate HR flavonoids with higher antioxidant activity,with higher antioxidant activities than conventional extraction method and is beneficial to the release of related active ingredients.2.EPP and NEPP in AR and HR have been determined,and found that the content of AR and HR is not much different.The content of EPP and NEPP in AR is relatively high than HR,and the ratio of EPP content to NEPP content in AR and HR is 1:1 to 2:1.In both two materials,the main components of EPP are Epicatechin,Ononin,Calycosin,Genistein,Isoliquiritigenin,and Formononetin,while the main components of NEPP are Gallocatechin,Catechin,Epicatechin,Ononin,and Formononetin.EPP showed higher antioxidant activity in AR and HR,but antioxidant activity of NEPP was low.The content of polyphenols in AR and HR showed a positive correlation with antioxidant activity.The contents of amaio acid and total sugar(TS)were different in AR and HR.The content of Asp was highest and Cys was not detected and the content of other amino acids is basically the same.Finally,the content of total sugar in AR is higher than HR.3.The total polyphenol-extract and residue fluid of AR and HR are digested through the mouth,stomach and intestines.The release of their monomer component was reduced;however another composition was gradually released through the mouth and gastrointestinal digestion.They were mainly released in the stomach digestion.Main polyphenols of AR and HR was released after in vitro digestion:EPP:Gallocatechin,Catechin,Epicatechin,Calycosin-7-0-beta-D-glucoside,Calycosin and Formononetin,while the content of Hyperoside and Genistein were least.After digestion,high antioxidant activity was shown in the stomach and antioxidant activity of digestion fluid in different parts showed a positive correlation with the content of tea polyphenols in the digestion fluid.Bio-transmittance of AR and HR was overed 30%.