Development of methods for quantitation of the amount of flavonoids in the herb Аstragalus glycyphyllus L.

Aim – develop a method for the quantitative determination of the amount of flavonoids in the herb of Astragalus glycyphyllus.

Materials and methods. The object of the perennial wild herbaceous plant milk vetch – Astragalus glycyphyllus L., of the legume family – Fabaceae, harvested in the Kursk region during 2023-2024, was used as the object of the study. Differential spectrophotometry was used to quantitatively determine the content of flavonoids in plant materials. At the initial stage of the methodology development, the conditions for raw material extraction were determined, allowing for maximum extraction of flavonoids. Then, the most suitable conditions for complexation and spectrophotometry were selected empirically.

Results.  The highest yield of flavonoids from the herb of Astragalus glycyphyllus can be achieved if the following conditions are met: the degree of grinding of the raw material is 1 mm, the extractant is ethyl alcohol 70%, extraction with heating in a boiling water bath for 45 minutes. The optimal conditions for the reaction of complexation with a chromogenic reagent are the use of 2 ml of a 5% solution of aluminum chloride. Stable coloration of extracts from raw materials with aluminum chloride occurs after 15 minutes and lasts for 90 minutes. Optical density was measured at a wavelength of 405 ± 5 nm, which is the absorption maximum for this type of raw material. Since this value coincides with the absorption maximum of hyperoside with aluminum chloride, the standard sample of hyperoside from Fitopanatseya LLC was used. As the results showed, the content of the sum of flavonoids in the herb of Astragalus glycyphyllus in terms of hyperoside averages 1.11% ± 0.044%, the error of a single determination with a probability of 95% does not exceed 3.96%. Based on these values, it is recommended to establish the standard content of flavonoids in the herb of Astragalus glycyphyllus at least 1.0%.

Conclusion.  The developed methodology can be used to standardize the raw materials of "Astragalus glycyphyllus herb" by the content of flavonoids, as the main group of active substances, when developing regulatory documentation and determining the commodity characteristics of the analyzed raw materials.