METHOD FOR PREPARATION OF PROANTHOCYANIDINS FROM BAST OF BIRCH-TREE BARK

摘要

FIELD: chemistry.;SUBSTANCE: method includes extraction of disintegrated bast of birch-tree bark with water at temperature 95-100°C during 1.5-2.0 hrs., hydromodulus 10-15, separation of the water solution from the bark, its concentration up to 1/4 of initial volume, saturation with sodium chloride and separation of the formed precipitate by filtering. The filtrate is thrice extracted with ethyl acetate, then ethyl acetate extract is concentrated under vacuum up to 1/12-1/18 of initial volume. Concentrated ethyl acetate solution is diluted 5-7 times with chloroform and the proanthocyanidins are separated.;EFFECT: implementation of the claimed objective.;1 ex