SEPARATION AND PURIFICATION OF BETULIN BY TETRAHYDROFURAN-BENZENE EXTRACTION

Betulin extracted from bark of birch ( Betula platyphylla Suk.) was purified by several kinds of mix-solvents.Purification effects and structure of betulin were analyzed by UV and FT-IR spectra respectively.Quantitative analysis of betulin was performed by HPLC.Yield of crude betulin extracted from bark of birch was 34.52 % by weight.The most excellent mix-solvent was tetrahydrofuran-benzene.At the ratio of tetrahydrofuran to benzene 1:2 by volume,and ratio of betulin to mix-solvent was 1:30 (g:mL),yield of purified betulin was 31.19 %,with a purity of 94.53 % .Melting point of purified betulin was 248.9 - 251.3 ℃ and IR analysis conformed to literatures of the standard betulin sample.Comparing with the methods applied in the past,tetrahydrofuran-benzene extration is a simple and high efficient method to separate and purify betulin from birch bark.