大叶秦艽总环烯醚萜苷3种提取工艺优化及其抗氧化活性研究

Optimization of three extraction processes for total iridoid glycosides from Gentiana macrophylla and their anti-oxidant activity

目的 优化大叶秦艽总环烯醚萜苷回流提取、超声提取、超声-回流提取工艺,并评价其抗氧化活性。方法 在单因素试验基础上,以乙醇体积分数、液料比、回流时间、提取次数、超声时间、超声功率为影响因素,总环烯醚萜苷含量为评价指标,响应面法优化3种提取工艺,再测定提取物对DPPH、OH~-自由基的清除率。结果 最优回流提取工艺为乙醇体积分数75%,液料比20∶1,回流时间100 min,提取次数2次,总环烯醚萜苷含量为62.75 mg/g;最优超声提取工艺为乙醇体积分数78%,液料比20∶1,超声时间42 min,超声功率204 W,总环烯醚萜苷含量为70.25 mg/g;最优超声-回流提取工艺为乙醇体积分数76%,液料比17∶1,超声时间29 min,回流时间72 min,总环烯醚萜苷含量为76.49 mg/g。超声-回流提取工艺所得提取物对DPPH、OH~-自由基的清除率高于其他2种提取工艺所得。结论 超声-回流提取工艺更适合大叶秦艽总环烯醚萜苷的提取。

AIM To optimize the reflux extraction, ultrasonic extraction and ultrasonic-reflux extraction processes for total iridoid glycosides from Gentiana macrophylla Pall. and to evaluate their anti-oxidant activity.METHODS With ethanol concentration, liquid-solid ratio, reflux time, extraction frequency, ultrasonic time and ultrasonic power as influencing factors, total iridoid glycosides content as an evaluation index, the three extraction processes were optimized by response surface method on the basis of single factor test. Then the scavenging rates of extracts on DPPH and OHfree radicals were investigated.RESULTS The optimal reflux extraction process was determined to be 75% for ethanol concentration, 20∶1 for liquid-solid ratio, 100 min for reflux time and 2 times for extraction frequency, the total iridoid glycosides content was 62.75 mg/g. The optimal ultrasonic extraction process was determined to be 78% for ethanol concentration, 20∶1 for liquid-solid ratio, 42 min for ultrasonic time, and 204 W for ultrasonic power, the total iridoid glycosides content was 70.25 mg/g. The optimal ultrasonic-reflux extraction process was determined to be 76% for ethanol concentration, 17∶1 for liquid-solid ratio, 29 min for ultrasonic time, and 72 min for reflux time, the total iridoid glycosides content was 76.49 mg/g. The extract obtained by ultrasonic-reflux extraction process demonstrated higher scavenging rates on DPPH and OHfree radicals than those obtained by the other two extraction processes.CONCLUSION Ultrasonic-reflux extraction process is more suitable for the extraction of total iridoid glycosides from G. macrophylla.