水解法制备石榴皮鞣花酸工艺研究

Study on preparation of ellagic acid by hydrolysis from pomegranate peel

建立了以60%乙醇超声提取石榴皮粉末,粗提物经石油醚萃取除去脂溶性物质,乙酸乙酯萃取,萃取物用酸水解法水解制备鞣花酸的方法。采用超高效液相色谱-质谱法(UPLC-MS)确定了乙酸乙酯萃取部位的主要成分为粟木鞣花素、安石榴苷、石榴亭A、鞣料云石素、石榴亭B、鞣花酸,并鉴定酸水解产物为鞣花酸。采用毛细管电泳法(CE)监测了乙酸乙酯萃取物的酸水解历程,结果表明,随着水解时间的增加,乙酸乙酯萃取物的电泳峰不断减少,而水不溶物鞣花酸的质量不断增加。正交实验考察了水解时间、水解温度、酸浓度对鞣花酸得率的影响,最优水解条件为:水解时间6h、温度100℃、硫酸浓度1.0mol/L,鞣花酸得率达32.7%。

Preparation of ellagic acid from pomegranate peel by hydrolysis was developed. Pomegranate peel powder was extracted with 60% ethanol by means of ultrasonic-assisted extraction to obtain crude extract. After removal of lipophilic ingredients by extracting with petroleum ether,crude extract was extracted with ethyl acetate,and the ethyl acetate fraction was hydrolyzed to produce ellagic acid. With the ultra performance liquid chromatography-mass spectrometry,the main ingredients in the ethyl acetate fraction were identified as castalagin,punicalagin,granatin A,corilagin,granatin B and ellagic acid,and the hydrolysis product was identified as ellagic acid. The hydrolysis process of the ethyl acetate fraction was monitored by capillary electrophoresis. It had been found that with the increase of hydrolysis time,the number of peaks in electropherogams was reduced ,while the weight of ellagic acid increasing. With the orthogonal experiment,the influences of hydrolysis time,hydrolysis temperature,as well as acid concentration on the ellagic acid yield was investigated. It turned out that optimum conditions of hydrolysis were as follows：hydrolysis time of 6h, hydrolysis temperature at 100℃,and sulfuric acid of 1.0mol/L,with the ellagic acid yield of 32.7%.