HPLC-UV Analysis of Flavonoid Glycosides in the Herb of Astragalus (A. dasyanthus, A. varius, A. testiculatus, A. henningii), Growing in the Volga Region

Abstract

Introduction. The search for new promising sources of biologically active substances is one of the tasks of modern pharmacognosy. Among the huge variety of species of the genus Astragalus L., only a few of them have been studied. In addition, none of them is included in the current edition of the State Pharmacopoeia of the Russian Federation. In our opinion, the study of four species of this genus of Astragalus L. (A. dasyanthus, A. varius, A. testiculatus, A. henningii) growing in the Volga region is of interest.Aim. Study of the glycoside composition of flavonoids in the astragalus herb of four species (A. dasyanthus, A. varius, A. testiculatus, A. henningii) by HPLC-UV using external standards.Materials and methods. The material was samples of astragalus grass (A. dasyanthus, A. varius, A. testiculatus, A. henningii), collected on the territory of the Saratov region in accordance with the basic rules of collection and preparation and dried to an air-dry state. Aqueous-alcoholic extracts (1 : 50) were analyzed. Qualitative and quantitative analysis of flavonoid glycosides was carried out on an Agilent 1260 chromatograph (Agilent Technologies, USA) equipped with a diode array detector, manual sample injection (Agilent G1328C manual injector, Agilent Technologies USA) and an Agilent Open Lab CDS system for collecting and processing chromatographic data. The elution gradient was selected individually using 0.1 % phosphoric acid/acetonitrile solution as solvents. Compounds were identified by retention times and UV spectra of reference standards (RS). The quantitative content of each detected component was expressed in mg/g of dry raw material. All studies were repeated five times, the results were statistically processed using MS Exсel 2010.Results and discussion. The chromatographic profiles of aqueous-alcoholic extracts from the herbs of four types of astragalus were studied. Differences were found in both the qualitative composition and quantitative content of flavonoid glycosides in the grass of the analyzed species. The largest number of compounds was found in the herb of A. varius (6 compounds), 4 compounds were identified in the herb of A. dasyanthus and A. henningii, and 3 compounds were identified in the herb of A. testiculatus. The dominant components in the herb of A. henningii are orientin and rutin, in the herb of A. testiculatus and A. varius it is cynaroside, and in A. dasyanthus it is rutin.Conclusion. A HPLC-UV method was developed for determining the quantitative content of flavonoid glycosides in extracts from the herbs of four species of astragalus (A. dasyanthus, A. varius, A. testiculatus, A. henningii) and the chromatographic profiles of the analyzed samples were studied.