VALIDATION OF THE METHODOLOGY OF QUANTITATIVE DETERMINATION OF FLAVONOIDS IN THE HERBAE OF Cirsium arvense (L.)

Relevance. One of the main groups of active substances of the Cirsium arvense L. are flavonoids, among which apigenin predominates. An urgent problem is the study of new types of medicinal plant raw materials and their introduction into medical practice, which requires research on the development of methods for the quantitative determination of the main group of BAS and validation of the method. The purpose of the work. Validation evaluation of the method of quantitative determination of flavonoids in the herba of the Cirsium arvense L. Material and methods. The object of the study is samples of the herba of the Cirsium arvense L. The quantitative determination of flavonoids was carried out by differential spectrophotometry with the selection of optimal extraction conditions, and the method was validated. Results. A method for the quantitative determination of the amount of flavonoids in terms of apigenin (λmax = 388 ± 2 nm) was developed. The optimal parameters of extraction of flavonoids were determined: the extractant-ethyl alcohol 40%, the ratio of raw materials and extractant 1: 30, the degree of grinding – 2 mm, the extraction time-30 minutes, three-time extraction, the complexing agent-1 ml of 2% aluminum chloride solution, the reaction develops within 45 minutes and the complex remains stable for 1 hour. The content of the sum of flavonoids in terms of apigenin is 2.78 ± 0.09%. Validation of the method was carried out according to the following parameters: linearity, correctness and precision. It was found that within the limits of the measured concentrations (optical density 0.241–0.389), the dependence of the apigenin content on the theoretical content of flavonoids in the herba of the Cirsium arvense L. is linear. The correctness of the method was established by measuring the quantitative content of the sum of flavonoids in solutions with a known concentration of apigenin and it was found that the values lie within the confidence intervals of the corresponding average results. Precision was studied by the indicators-repeatability (convergence); intra-laboratory and inter-laboratory reproducibility, while it was found that the relative error of the average result did not exceed 10%. Conclusions. The linear nature, correctness and precision of the developed methodology for the quantitative determination of flavonoids in the herba of the Cirsium arvense L. in terms of apigenin and the possibility of its further use for the standardization of the studied raw materials are justified.