Phytochemical analysis and antioxidant activity of the herb of four types of astragalus belonging to the section Dissitiflori DC.

Introduction. According to numerous studies, it is known that representatives of the genus Astragalus L. contain a variety of biologically active compounds: alkaloids, flavonoids, triterpene saponins, nitrogen-containing compounds, including amino acids, phenolic acids and their esters, coumarins, higher fatty acids, polysaccharides, vitamins B, C, E, PP, salts of glycyrrhizic acid, trace elements, tannins, essential oils, gums, etc. It is relevant to conduct a phytochemical analysis of herbs of new species of the genus Astragalus L., as well as screening the antioxidant activity of their extracts. The types of astragalus belonging to the Dissitiflori DC section can be a promising source of biologically active substances with an antioxidant effect.

Aim. To conduct a comparative phytochemical analysis and scoring of the antioxidant activity of aqueous extracts from the herb of four species of astragalus section Dissitiflori growing in the Saratov region.

Materials and methods. The objects of the study were dried herbs of Astragalus macropus Bunge, Astragalus zingeri Korsh., Astragalus varius S.G. Gmel. and Astragalus ucrainicus Klok. et M. Pop., collected in the Saratov region in 2023 and dried to a residual moisture content of no more than 14 %. The quantitative assessment of the content of tannins was carried out by the permanganometric method (titrant – 0.02 M potassium permanganate solution). The quantitative content of ascorbic acid was established by direct titration using a 0.0001 M solution of sodium 2,6-dichlorophenolindophenolate as a titrant. Antioxidant activity was determined by permanganometric titration in an acidic medium according to a patented technique. The antioxidant activity index was calculated in terms of flavonoid compounds known for their antioxidant activity: rutin, quercetin (mg/ml). Antiradical activity was assessed using the DPPH test. All analyses were performed in triplicate, the data were processed using standard statistical methods, using MS Excel packages, 2021.

Results and discussion. During the experiment, the herb of the genus Astragalus L. section Dissitiflori was analyzed for the content of tannins and ascorbic acid, and the antioxidant activity of extracts from the herb was determined by two methods. It was found that the highest content of tannins is observed in the herb A. macropus Bunge (2.27 ± 0.06 %) and A. zingeri Korsh. (2.23 ± 0.05 %); the highest content of ascorbic acid is in the herb A. varius S.G. Gmel. and A . zingeri Korsh. (0.04 ± 0.001 %). The highest antioxidant activity was observed in the extraction of A. ucrainicus Popov et Klok. from grass, which contains 23.03 ± 0.57 mg/g and 15.71 ± 0.39 mg/g of oxidizing substances in terms of rutin and quercetin, respectively, and antiradical activity in A. zingeri Korsh. (IC₅₀ 465.20 ± 12.2 mcg/ml).

Conclusion. Analysis of the grass of four species of the genus Astragalus L. section Dissitiflori revealed a high content of tannins and ascorbic acid, as well as the presence of pronounced antioxidant activity in extracts from the grass of the analyzed species.

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