Validation of the method of quantitative determination of the amount of flavonoids in the herb Astragalus dasyanthus L

The main group of active substances of Astragalus dasyanthus are flavonoids, among which hyperoside predominates. Therefore, we made an attempt to standardize the raw Astragalus dasyanthus woolly flowering in the content of flavonoids, in terms of hyperoside. The development of a fairly accurate and simple method for the quantitative determination of flavonoid content, as well as its validation, is an urgent problem. Therefore, the aim of our work was to validate the method for quantitative determination of the amount of flavonoids in the herb of Astragalus dasyanthus. Material and methods. The object of the study was herb Astragalus dasyanthus, harvested in 2019 - 2020 in the Kursk region during the period of mass flowering of the plant. The herb was dried to an air-dry state and ground to a particle size of 1 mm. When developing the methodology, optimal conditions were established for extracting the sum of flavonoids from raw materials: the degree of grinding of the raw material is 1 mm, the extractant is ethyl alcohol 70%, the ratio of raw material to extractant 1: 100, heating for 45 minutes. When studying the conditions of spectrophotometry, it was found that the use of 2 ml of a 5% solution of aluminum chloride is optimal. Results. Validation of the methodology was carried out according to the parameters of linearity, repeatability, reproducibility and correctness of the methodology. Based on the results obtained, it was found that within the concentration measurements (starting from an optical density of 0,33 to an optical density of 0,89), the dependence of the content of hyperoside on the mass of a sample of raw materials is linear. Repeatability of the method was determined on one sample of raw materials in 6 replicates. The acceptance criterion was expressed by the standard deviation relative value, which should not exceed 10%. It amounted to 4,38%, which testifies to the precision of the technique under repeatability conditions. Determination of reproducibility of the method was performed by 2 researchers. The study was carried out on 3 samples in 3 replicates. As a result of our studies, the relative standard deviation was 4,67%, which indicates the precision of the technique under reproducibility conditions. The correctness of the technique was established by measuring the content of hyperoside in solutions obtained by adding the required amount of a standard solution of hyperoside (0,25 ml, 0,5 ml) to the test solution. In the developed methodology, the recovery percentage ranges from 9,15% to 102,35%, its average value is 100,36%. There is no systematic error in the methodology, the relative uncertainty at a confidence level of 0,95 does not exceed 2,89%. Conclusion. The developed method of quantitative determination of flavonoids in the herb of Astragalus dasyanthus can be used for standardization of raw materials «Herb Astragalus dasyanthus» the content of flavonoids.

Astragalus dasyanthus L, flavonoids, spectrophotometric method, validation of the method