DEVELOPMENT AND VALIDATION OF A METHOD FOR QUANTITATIVE ANALYSIS OF THE TOTAL CONTENT OF FLAVONOID COMPOUNDS IN THE MEDICINAL PLANT MATERIAL BIDENTIS CERNUAE HERBA

Relevance. Pharmacognostic studies of Bidens cernua L. (bur-marigold) herb samples collected in different ecological and geographical zones of Russia have shown that this species is a valuable source of biologically active compounds. Previously considered mainly as an admixture to the official species Bidens tripartita L., it is a promising plant for introduction into medical practice as a new type of raw material – a source of essential oil, polyacetylene and phenolic compounds. The aim of the study was to develop and validate a method for the quantitative determination of the total flavonoid content in bur-marigold herb. Materials and methods. Samples of the aerial part (leaves and flowers) of B. cernua were studied. Air-dried raw materials were extracted with 70% ethanol according to the procedure described in OFS.1.5.3.0006.15 of the State Pharmacopoeia of the Russian Federation, XIV edition. Spectrophotometric analysis revealed that the differential absorption spectrum of the obtained extract in the visible region with a maximum at 425 nm correlates with the absorption curve of a quercetin standard solution. Results. It was found that the maximum amount of flavonoids is extracted with 70% ethyl alcohol from raw materials ground to 1 mm particles, using a single extraction for 1 hour at a raw material to extractant ratio of 1 : 60. Based on these conditions, a methodological approach was developed and validated for the following parameters: specificity, linearity, analytical range, accuracy, and precision. The method was tested on a series of bur-marigold samples from various regions of Russia. Conclusions. A spectrophotometric method for the quantitative determination of the total flavonoids in terms of quercetin has been developed, suitable for quality control of the new type of medicinal plant material "Bur-marigold herb".