Quantitative determination of tannins by titrimetry and spectrophotometry in raw materials of some representatives of the genus Rumex of three growing seasons

Introduction. Study of the chemical composition of medicinal plant raw materials and comparative analysis of the dynamics of accumulation of biologically active substances in related medicinal plants is necessary for the creation of highly effective and safe drugs. Similar metabolome to the officinal representative of the genus Rumex (hereinafter referred to as R .) – R. confertus – the metabolome of species widely distributed in Russia: R. crispus , R. obtusifolius , R. aquaticus , which determines the perspectivity of studying these species. Scientific and practical interest is represented by the study of the group of biologically active substances possessing antibacterial activity – tannins at different phenological stages of plant development. Aim. Quantitative determination of tannins by permanganatometry and spectrophotometry methods in underground organs of R. confertus , R. crispus , R. obtusifolius , R. aquaticus , harvested in different phases of vegetation: regrowth, flowering and withering periods. Materials and methods. Aqueous extracts from underground organs of the studied Rumex species were analyzed. Extractions and solutions obtained during the study were analyzed by permanganatometry, spectrophotometry and HPLC. The compounds from the group of tannins were identified by the wavelength of absorption maximum. Results and discussion. The quantitative content of tannins was evaluated by permanganatometry, spectrophotometry and HPLC. Conclusion. Tannins were detected and quantified in extracts from underground organs of R. confertus , R. crispus , R. obtusifolius , R. aquaticus and the dependence between their quantitative content and vegetation phase was analyzed.