新鲜枸杞叶中黄酮提取工艺的优化及抗氧化性分析

Optimization of Extraction Technology and Analysis of Antioxidant Activity of Flavonoids from Fresh Lycium barbarum Leaves

为了合理利用新鲜枸杞叶中的有效成分,获得其中更多的活性物质,试验对新鲜枸杞叶中黄酮的提取工艺进行优化,采用单因素、响应曲面设计确定新鲜枸杞叶中黄酮的最佳提取工艺参数,并探讨黄酮提取液对DPPH、·OH以及ABTS自由基的影响。单因素试验结果表明,超声温度、料液比、乙醇体积分数、超声功率等各因素均对新鲜枸杞叶中黄酮提取率有较大的影响。经过响应面法优化,得到新鲜枸杞叶中黄酮的最佳提取条件为超声温度60℃、料液比1∶30、乙醇体积分数65%、超声功率300 W,在此条件下,新鲜枸杞叶中黄酮实际提取率可达7.742 1%,高于理论值(7.706 1%)。抗氧化活性研究发现,不同提取液对自由基的清除影响不同,当新鲜枸杞叶黄酮提取液质量浓度为5 mg/mL时,对各项自由基均有显著的清除效果。通过响应面法优化新鲜枸杞叶黄酮的超声提取工艺,所提取的枸杞叶中黄酮具有显著的体外抗氧化活性。

In order to rationally utilize the active ingredients in fresh Lycium barbaru leaves and obtain more active substances. In this study, the extraction technology of flavonoids from fresh Lycium barbarum leaves was optimized. The optimal extraction parameters of flavonoids from fresh Lycium barbaru leaves were determined by single factor and response surface design, and the effects of flavonoids extract on DPPH,·OH and ABTS free radicals were investigated. The results of single factor experiments showed that the factors such as ultrasonic temperature, solid-liquid ratio, ethanol volume fraction and ultrasonic power had great influence on the extraction rate of flavonoids from fresh Lycium barbaru leaves. After optimization by response surface methodology, the optimal extraction conditions of flavonoids in fresh Lycium barbarum leaves were obtained as follows: 60℃ of ultrasonic temperature, 1: 30 of solid-liquid ratio, 65% of ethanol concentration, and 300 W of ultrasonic power. Under these conditions, the actual extraction rate of flavonoids in fresh Lycium barbaru leaves was higher than the theoretical value(7.7061%), reaching 7.7421%. Antioxidant activity studies showed that different extracts had different effects on scavenging of free radicals. When the mass concentration of flavonoids extract from fresh Lycium barbaru leaves was 5 mg/mL,it had significant scavenging effects on various free radicals. Through optimization of the ultrasonic extraction process of flavonoids from fresh Lycium barbaru leaves by response surface methodology, the flavonoids extracted from Lycium barbaru leaves had obvious in vitro antioxidant activity.