Abstract: The technological conditions for extraction and purification of betulin from the outer bark of white birch were investigated. The suitable extraction conditions were determined as follows: amount of bark 30 g, the size of bark particle 0.42-1.16 mm, chloroform was used as extraction solvent, extraction time 7 h. The yield of light-yellow crude extract obtained under aforesaid conditions reached 38.5%. Betulin with high purity was obtained by recrystallization, and the suitable recrystallization conditions were determined as follows: isopropanol was a suitable solvent for recrystallization of betulin, and the ratio of crude extract/isopropanol was 1:20(g:mL); crystallization temperature -5℃, crystallization time 1 h. The yield of betulin was 41.4%, melting point was 245-254℃, and purity was 95.4%.

Key words: white birch bark, betulin, extraction, recrystallization