Isolation,Identification,Antioxidant Evaluation And Pharmacokinetic Study Of The Major Chemical Constituents Of Ephedra Sinica

Ephedra sinica Stapf is a plant in Ephedra?genus?,Ephedraceae?family?.The original plants of the herbal medicine Ephedrae Herba in Chinese Pharmacopoeia include E.sinica Stapf,E.equisetina Bge.and E.intermedia Schrenk et C.A.Mey.The plant's dry herbaceous stems are the medicinally used part.As a traditional Chinese medicine,Ephedrae Herba is usually used in the form of decoction for sweating,dispelling cold,ventilating lung and relieving asthma,and diuretic deswelling.Mongolian medicine uses E.sinica powder in compound prescription for treatment of liver diseases etc.In this paper,the chemical constituents of E.sinica were extracted,separated,purified,and structurally identified.The effects on DPPH free radical scavenging,?-glucosidase inhibition and other biological activities of the extracts,fractions and purified compounds were evaluated.Pharmacokinetic properties of the major chemical constituents of E.sinica the plant powder and in E.sinica combined Terminalia chebula fruit as used in Mongolia medicine were also studied to provide theoretical and experimental bases for the traditional application of E.sinica.Sephadex LH-20,ODS and prep-HPLC were used to isolate and purify the chemical constituents of E.sinica.Ten compounds were identified by NMR and HPLC-MS data as ephedrine?1?,pseudoephedrine?2?,catechin?3?,epicatechin?4?,gallocatechin?5?,epigallocatechin?6?,ephedrannin Te₁?7?,rutin?8?,4'-methoxy isovitexin-2"-O-?-L-rhamnopyranoside?9?andapigenin-6,8-di-C-?-D-glucopyranoside?vicenin-2,10?.Among them,compounds 1 and 2 are alkaloids,compounds 3-7 are flavan-3-ols,and compounds 8-10 are flavonoids.The biological activities of the 70%acetone extract,four fractions Fr1-Fr4 from Sephadex LH-20 column and 10 compounds isolated from E.sinica were tested for DPPH free radical scavenging,?-glucosidase inhibition,etc.Among them,the extract and Fr1-Fr4 had inhibitory activities on?-glucosidase;The extract,Fr1-Fr4 and compounds 3-10 had DPPH scavenging activity;Fr4 and compounds 6-7 had maltase inhibitory activity.A quantitative method for the 10 chemical constituents of E.sinica in rat plasma was established,and 9 compounds were detected in the plasma after gavaging E.sinica to rats.Among them,Ephedra alkaloids?1-2?were most well absorbed as highest concentration of the alkaloids was observed in plasma.Mongolian medicine usually uses the powder of herbal medicines,and Gurigumu-7 contains E.sinica and T.chebula fruit.Therefore,the pharmacokinetic properties of these Ephedra chemical constituents were investigated after gavaging to rats of E.sinica powder,and the results were compared with that after gavaging a mixture of E.sinica and T.chebula fruit powder.When E.sinica powder alone was administered,9 compounds showed shorter T_maxax and higher blood concentration than the combination of E.sinica and T.chebula fruit were gavaged.However,the combination displayed these chemical constituents of E.sinica in plasma at notable concentrations for longer time.The results indicated that T.chebula fruit slowed down the absorption speed of the chemical constituents of E.sinica,and consequently,reduced the possible reverse effects of E.sinica alkaloids.In the group gavaged with E.sinica,the flavan-3-ol monomers showed second absorption peaks with time,indicating that the tannin polymers in E.sinica was decomposed into flavan-3-ol monomers and absorbed into blood again.In brief,this research isolated and purified the major chemical constituents,especially the phenolic compounds from E.sinica,evaluated their biological activities and pharmacokinetic properties.The obtained results provided experimental bases for further study of E.sinica in the Mongolian compound medicine Gurigumu-7.It also provided theoretical bases for better development and use of E.sinica resources.