METHOD OF OBTAINING PURIFIED POLYSACCHARIDE COMPLEX FROM BURDOCK LEAVES Russian patent published in 2024 - IPC C08B37/18 

FIELD: pharmaceuticals.

SUBSTANCE: method of obtaining water-soluble polysaccharides from leaves of burdock is performed using three-fold extraction of raw materials crushed to 0.5 mm with purified water, heated to boiling point at a ratio of 1 g of raw materials: 10 ml of extractant. Extraction is performed in an ultrasonic bath with a frequency of 30 kHz for 10 minutes at a temperature of 80°C. The extracts are combined, the plant material is separated by filtration, water-soluble polysaccharides are precipitated with a threefold amount of an aqueous solution of ethanol relative to the aqueous extract, with stirring, cooling in a freezer at a temperature of -18°C for 30 minutes. The resulting precipitate is filtered through a pre-dried ashless paper filter under vacuum, the precipitate is washed on the filter sequentially with a mixed solution of ethyl alcohol and purified water, taken in a volumetric ratio of 3:1, respectively, with a ratio of raw material:ethanol solution equal to 1 g:10 ml, respectively, and a mixture of ethyl acetate and ethyl alcohol, taken in a volumetric ratio of 1:1, with a ratio of raw material:solution of ethyl acetate and ethanol equal to 1 g:10 ml, respectively. The filter is dried with sediment at a temperature of 100 to 105°C to constant mass. Before the washing stage, the sediment is cleaned of impurities by dissolving this sediment in a purified water heated to 90°C at the ratio raw material:water 1 g:10 ml, then adding finely dispersed aluminum oxide powder to the resulting solution at a mass ratio of raw material:aluminum oxide equal to 1:0.5, keeping the mixture for 30 minutes and filtering under vacuum. Then the resulting filtrate is passed sequentially at a speed of 50 ml/min through ion exchange columns with an anion exchange resin in the hydroxyl form AB-17-8 and a cation exchange resin in the hydrogen form KU-2-8, taking into account the capacity of the ion exchange resins until the eluate pH is 6.5–7.5 and to a degree of purity of the polysaccharide complex equal to 98.5%. Next, the complex of water-soluble polysaccharides is precipitated by adding again to the eluate a threefold amount of ethanol relative to the aqueous solution of the eluate with stirring, cooling in the freezer at a temperature of -18°C for 30 minutes. Then the resulting precipitate is filtered through a pre-dried ashless paper filter under vacuum. At the same time, at all stages of sediment filtration, filtration is carried out under vacuum at a residual pressure of 0.3–0.6 atm, and at all stages of obtaining a complex of water-soluble polysaccharides, an aqueous solution of ethanol is used at a concentration of 96%.

EFFECT: invention is aimed at extracting a purified water-soluble polysaccharide complex from burdock leaves with a degree of purity equal to 98.5%, with a yield of the target product of up to 10.05% in terms of absolutely dry raw materials in the absence of the use of hazardous and toxic substances.

1 cl, 3 dwg, 1 ex