Development and validation of a procedure for the quantitative determination of polysaccharides in linden flowers

Introduction. Linden flowers are pharmacopeial medicinal plant raw material (MPRM), containing polysaccharides. Nowadays, according to the current regulatory documentation, the assessment of the content of biologically active substances (BAS) is carried out only for flavonoids. To improve the standardization of linden flowers, the development and validation of the spectrophotometric procedure of polysaccharides determination with anthrone reagent is proposed to be relevant. Objective: To develop and validate a procedure for the quantitative determination of polysaccharides in linden flowers. Material and methods. In the development and validation of the procedure we used the method of differential spectrophotometry based on the complexation reaction of linden hydrolysate sugars with an anthrone reagent. The resulting complex has an absorption maximum of 625±2 nm, the reference standard (RS) of glucose was used as a comparison solution. The influence of extraction conditions on the yield of polysaccharides from raw materials was studied: the size of raw material particles, the ratio of raw material and extractant, the duration of extraction, as well as the selection of optimal conditions for the complexation reaction. Validation of the procedure was carried out according to the indicators: specificity, linearity and representativeness, trueness, repeatability, intermediate precision (reproducibility). Results. The optimal parameters of polysaccharides extraction from raw material were determined (three-stage extraction with distilled water on a water bath, the ratio “raw material – extractant” – 1:30 for 30 minutes, the size of raw material particles – 2,0 mm). The conditions of complex formation reaction were selected (ratio “extract – complexing agent” – 1:2, complexing agent is anthrone reagent, appearance of stable coloring of the solution in 25 minutes). During the validation of the developed procedure, it was found that the validation characteristics are within the criteria of acceptability. In the analysis of linden flowers, it was found that the content of reducing sugars in the polysaccharide composition was 1,9–3,1%. Conclusion. Optimal parameters of polysaccharide extraction from raw materials were determined, conditions of complex formation reaction were selected, and the procedure validation was carried out. The total content of reducing sugars in the polysaccharide composition in terms of absolutely dry raw material in linden flowers using differential spectrophotometry was determined.