METHOD OF DIHYDROQUERCETIN PRODUCTION Russian patent published in 2008 - IPC A61K36/15 A01D11/02 A61P39/06 A61P39/02 A61P9/10 A61P9/14 A61P29/00 A61P35/00 

FIELD: medicine; pharmacology.

SUBSTANCE: wood of Siberian or Daurian larch is debarked, cleaved and dried at 40-50°C to residual moisture 23-27%. Dried wood is chopped, and soluble substances are extracted with 75-85% ethyl alcohol aqueous solution at temperature 45-50°C in ratio raw material:extracting agent 1:(7-10). Further extracting agent is distilled off, and sawdust is supplied to press for additional alcohol return. Then extract aqueous part is cooled to 20-25°C within 20-30 minutes for isolation of resinous impurity accompanying dihydroquercetin (DHQ). Deresined extract aqueous part is added with methyltertbutyl ether (MTBE) in ratio 1: (0.3-0.45), and DHQ is reextracted within 2-3 hours. Extract ether part is isolated separate from aqueous part through sedimentation within 2-2.5 hours and supplied to MTBE evaporation, while target product is crystallised of hot water. Invention enables to produce DHQ with yield 2.2-2.5% of bone-dry wood mass with grade 90-96%.

EFFECT: simplification of process and production of high-quality product.

4 cl, 2 ex