Development of methods for obtaining polysaccharides from birch leaves (Betula Pendula Roth., Betula pubescens Ehrh.)

Abstract

The development of a complex technique for the extraction and purification of polysaccharides from birch leaves (Betula pendula Roth., Betula pubescens Ehrh.) (PSfB) was the purpose of this study. The following characteristics were used as criteria for evaluating the effect of the parameters studied on the production of target substances: yield of PSfB (gravimetric method), protein content (spectrophotometric method), molecular weight distribution (high performance exclusion chromatography) and degree of purification from low molecular weight impurities (LMWI) (IR) spectroscopy). During the experiment, the optimal parameters were determined at various stages of obtaining the PSfB: degree of raw materials grinding - 1.2-3 mm, pH of the extradant (purified water with pH=7), the ratio of raw materials: extradant (1: 20), extraction temperature (50 °C), temperature and degree of evaporation (50 °C; 4 times), the ratio of concentrate: ethanol(1: 3) and the method of purification from the LMWI (ultrafiltration). The result of this work is an optimized method for obtaining PSfB, allowing to achieve high yield without loss of product quality (minimum allowable content of low molecular weight impurities with the highest content of high molecular weight fractions). This technique is the basis for the development of laboratory regulations for obtaining an active pharmaceutical substance based on polysaccharides from birch leaves.