METHOD FOR MAKING NATIVE FORM OF DIHYDROQUERCETIN Russian patent published in 2009 - IPC A61K36/15 A61P39/06 

FIELD: medicine.

SUBSTANCE: invention concerns pharmaceutical, food, cosmetic industry. Wood substance of larch root is chopped to particle size 0.5-1.5 mm and at least twice extracted at temperature less than 45°C in cavitation condition at maintained ethanol concentration within 80-86%. Sawdust is separated from the extract. The prepared extract is kept within 20-30 hours and separated from recovered resins and oils. The extract is steamed to concentration 40-45% and separated from recovered resins and oils again. The extract is steamed to concentration 8-11% and separated from recovered resins and oils again. Then the extract is recrystallised by freezing to temperature -20 to -40°C within 6-8 hours. Defrosting is performed 24 to 36 h at 5-10°C. Defrosted solution is elutriated. The prepared solution is filtered and dried in nitrogen atmosphere at temperature not exceeding 40°C. Thus dihydroquercetin in native form of purity 92-96% is prepared.

EFFECT: invention allows for high-yield native DHQ per a unit of initial wood, simplified technological process, reduced consumption of organic solvents and electric power.

1 ex