Identification and Quantitative Determination of Flavonoids by HPLC-UV Method in the Raw Materials of Some Representatives of the Genus <i>Rumex</i> of Three Vegetation Time

Introduction. The study of the dynamics of accumulation of biologically active substances (hereinafter – BAS) in relation to the phonological phases of plant development is of great scientific and practical interest. The quantitative content of aglycones and glycosides of flavonoids depends on the life cycle of the plant and its vegetation phase. Aim. To identify and quantify flavonoids in the underground organs of Rumex confertus Willd., Rumex aquaticus L., Rumex crispus L. and Rumex obtusifolius L. harvested during different phases of vegetation. Materials and methods. Extracts from the underground organs of the studied plants, obtained according to the method from the pharmacopoeial article on R. confertus , were analyzed. Chromatographic separation and detection were performed on a Nexera-i LC-2040 high-performance liquid chromatograph (Shimadzu Corporation, Japan). The chromatograph was equipped with a column thermostat, chromatography column Grace HPLC-COLUMN 250 × 4.6mm platinum C8-EPS 5 mm (Grace, США) and Guard column Phenomenex SecurityGuard TM Cartridges Widepore C18 4 × 3,0 mm, a degasser, an autosampler (injection volume: 10 µl), and an ultraviolet detector. Detection was carried out at a wavelength λ = 365 ± 2 nm. Mobile phase contains 0.1 % phosphoric acid in water (v/v) (eluent A); acetonitrile (eluent B) with flow rate: 0.9 ml/min. Results and discussion. All studied objects were analyzed. The authenticity of the substances contained were confirmed using the external standard, and their quantitative content was determined. The discovered and quantified substances were: 3-O-rutinoside of quercetin (rutin), 3-O-rutinoside of isorhamnetin (narcissin), 3-O-glucoside of kaempferol (astragalin), luteolin, kaempferol and isorhamnetin. 7-O-glucoside of luteolin (cynaroside) and 7-O-beta-D-glucoside apigenin (cosmosiin) were not found. The aglycone luteolin had the biggest share in the total quantitative content of flavonoids. It is noted that this aglycone is contained in larger quantities in relation to other flavonoids in all studied objects, regardless of the phase of vegetation. Conclusion. In the process of the research, a method for the quantitative determination of flavonoids in alcohol-water extracts was developed. Aglycones and glycosides of flavonoids were identified and quantified in the underground organs of R. confertus Willd., R. aquaticus L., R. crispus L. and R. obtusifolius L. of three different vegetations.