一种高效的白桦树皮中白桦脂醇分离、纯化方法

通过比较白桦树皮中白桦脂醇的不同的提取方法,获得一种简单、高效的白桦脂醇提取、纯化方法。通过对不同浸提时间比较、超声震荡方法及旋转蒸发仪回收提取3种白桦脂醇提取方案的比较,进一步利用甲醇-氯仿重结晶法、无水乙醇重结晶法及大孔吸附树脂层析法对获得的白桦脂醇初提取物进行纯化。获得了白桦脂醇提取及纯化的最佳方案。用95%乙醇溶液,液固比50∶1(mL∶g)浸泡白桦树皮样品120 h后,用滤纸过滤,收集滤液,将滤液50℃加热回流5 h,减压蒸馏得到米白色固体粉末。接着以70 mL乙酸乙酯为溶剂,将得到的固体加热回流90 min,趁热过滤。滤液使用坩埚50℃浓缩至干。再以无水乙醇为溶剂进行重结晶,无水乙醇∶固体=30 mL∶1 g,-20℃重结晶,重结晶产率可达38.00%,最高纯度达到99.81%。优化后的白桦脂醇提取纯化方法操作简便,产量较高、试剂安全,是一种可用于规模化提取的有效方法。

An Efficient Method for Separation and Purification of Betulin from Birch Bark

The experiment was conducted to obtain a simple and efficient method for extracting and purifying betulin from the bark of birch by comparing different methods. By comparing three extraction schemes of betulin by different extraction time, ultrasonic oscillation method and rotary evaporator recovery. And methanol-chloroform recrystallization method, absolute alcohol recrystallization method and macroporous resin chromatography were further used to purify the initial extract of betulin. The best extraction and purification scheme of betulin was obtained. The birch bark samples were soaked in 95% ethanol solution with a liquid-solid ratio of 50:1(mL:g) for 120 h. The filtrate was filtered by filter paper. The filtrate was heated and refluxed at 50℃ for 5 h. The white solid powder was obtained by vacuum distillation. Then 70 mL ethyl acetate was used as solvent, and the solid was heated and refluxed for 90 min, then filtered. The filtrate is concentrated to dry at 50℃ in a crucible. Then recrystallize with anhydrous ethanol as solvent. Anhydrous ethanol:solid=30 mL:1 g, recrystallize at -20℃. The recrystallization yield can reach 38.00%, and the highest purity can reach 99.80%. The optimized extraction and purification method of betulin is simple, high yield and safe reagent. It is an effective method for large-scale extraction of betulin.