Studies On Saponins Constituents From Astragalua Membranaceus(Fisch.) BGE. And The Structure Modification Of Astragaloside Ⅳ

Astragalus is one species of Astragalus genus, which belong to Family Legumin osae, the Astragalus membranaceus (Fisch.) Bge. var. mongholicus (Bge.) Hsiao and Astragalus membranaceus (Fisch.) Bge. were definited as the medicine in the2010v ersion of "Chinese Pharmacopoeia"(The1st). The roots of A.membranaceus, known as Huangqi in China, is the most important tonic in the traditional Chinese medicine, t o strengthen the superficial resistance, and to promote the growth of new tissue and the discharge of pus. The author of the paper has studied the constituents of A.memb ranaceus.Astragaloside Ⅳ, one typical compound of cycloastragenol-type triterpene glycosi de, which has significant features of cardiac, strengthen the immune, and so on. But astragaloside Ⅳ explained poor solubility and dissolution, and it has a high molecula r weight and low lipophilicity, which restriction its exploitaion. This is why we shoul d develop the derivatives of astragaloside IV. There is poor research about pharmacol ogy of astragaloside IV derivatives. To development the astragaloside IV derivatives, i n this study, we have modified the structure of astragaloside IV, and identified the st rcture of products.The constituents were extracted with ethanol、separated and purified with D101resin、silicon and Sephadex LH-20chromatography methods and their structures were elucidated by spectroscopic methods and chemical analysis. Ten compounds have bee n isolatesd from Astragalus membranaceus, and eight of them were identified as:dau costerol, astramembrannin Ⅱ, astragaloside Ⅰ, isoastragaloside Ⅰ, astragaloside Ⅱ, iso astragaloside Ⅱ, astragaloside Ⅲ, astragaloside Ⅳ.In this study, three ways have been used to modify the structure of astragaloside IV, they are acid hydrolysis, enzymatic hydrolysis and acetylation. The products were elucidated by TLC and spectroscopic methods, the product of acid hydrolysis is astragenol, which enzymatic hydrolysis is brachyoside B, and acetylation products are astragaloside I, isoastragaloside Ⅰ, astragaloside Ⅱ and isoastragaloside Ⅱ.