大黄总蒽醌的提取精制工艺研究

Extraction and purification techniques of total anthraquinones in rhubarb

目的:优选大黄总蒽醌的提取精制工艺。方法:以大黄总蒽醌的转移率为指标,采用单因素法确定提取工艺,通过正交试验确定阴离子交换树脂精制大黄总蒽醌的工艺。结果:最终确定的工艺为大黄药材用10倍量的30%乙醇浸泡,加热回流提取3次,时间分别为1,0.5,0.5 h,合并提取液,减压回收乙醇得浓缩液,将浓缩液用4%NaOH调pH到10,过处理好的阴离子交换树脂柱,用去离子水洗至流出液呈中性,用2 mol·L-1盐酸酸化,用10倍量体积的85%以上乙醇解析,回收乙醇,将析出的沉淀过滤,50℃以下干燥,得黄棕色粉末,总蒽醌含量54.5%,转移率34.6%。结论:制备得到的总蒽醌含量较高,采用阴离子交换树脂提取纯化大黄总蒽醌的工艺可行。

OBJECTIVE To study extraction and purification techniques of total anthraquinones （TA） in rhubarb. METHODS Transfer rate of TA in rhubarb was set as the index, factors such as ethanol concentration, heating time, and decoction times, which influenced the extraction were investigated. Crude extraction of rhubarb was purified with 201 × 4 anion exchange resin. Factors influencing purification of TA were also investigated. Process of refining TA from rhubarb was determined by orthogonal test. RESULTS Processes of extraction and purification of TA were determined as following： rhubarb was im mersed in 30% alcohol, with weight of 10 times rhubarb, and extracted by heating reflux for three times, for 60 min, 30 min and 30 min, respectively. Extract fluid was then filtered, and ethanol was concentrated by reduced pressure recovery. The pH value of concentrated fluid was adjusted to 10 with 4% NaOH, handled with anion resin column, elutriant of 85% ethanol was collected and concentrated to get refined TA, which was dried at 50 ℃. Powder of TA was yellow brown. TA content was 54. 5%, and extraction rate was 34. 6%. CONCLUSION Purification process to get TA in rhubarb is feasible.