Secondary metabolites from the roots of Astragalus maximus

Abstract

Background and objectives: Astragalus is one of the most abundant genera of flowering plants in Iran. There are a few reports on phytochemical investigation of this valuable genus. Saponins, flavonoids and polysaccharides have been reported as the most important metabolites in Astragalus species. In the present research, we aimed to identify the foremost constituents of Astragalus maximus. Method: Phytochemical analysis of the ethyl acetate (EtOAc) fraction of Astragalus maximus roots was performed using different methods of chromatography such as HPLC, SPE and preparative TLC. The structures of the isolated compounds were elucidated on the basis of extensive spectral evidence from 1D and 2D NMR including DQF-COSY, HSQC, HMBC, and DEPT, in comparison with reported values in the literature. Results: Analysis of the extract yielded three flavonoids namely liquiritigenin, formononetin, isoquercitrin and one acylated cycloartane-type saponin, astragaloside I. Conclusion: According to the results of our study, cycloartane-type saponin and flavonoids were the important metabolites in A. maximus.