乙醇浸提苦荞茶和雀嘴茶中的总黄酮及羟自由基清除活性探究

Study on Ethanol Extraction of Flavonoids from Buckwheat Tea and Sparrow Mouth Tea and Scavenging Effect on Hydroxyl Radicals

优化苦荞茶和雀嘴茶中总黄酮提取的较佳实验条件,并探究总黄酮提取液对羟自由基的清除活性.以提取液中总黄酮收率为考察指标,乙醇浸提苦荞茶和雀嘴茶中的总黄酮,考察乙醇浓度、料液比、浸提温度和时间单因素对浸提液中总黄酮收率的影响,设计正交实验确定较佳的提取条件.较佳实验条件为50%乙醇水溶液,料液比0.5∶40(g·mL),浸提温度和时间分别为60℃和2.5h,苦荞茶和雀嘴茶提取液中总黄酮收率高达21.64%和19.41%;苦荞茶和雀嘴茶提取液对羟自由基清除效果优于相同浓度相同体积的BHT.乙醇浸提法是苦荞茶和雀嘴茶中总黄酮提取的有效方法,提取液中获得的总黄酮对羟自由基具有较强清除活性.

Ethanol extractions of total flavonoids from Buckwheat tea and Sparrow mouth tea were optimized and scavenging effects on hydroxyl radicals of the extracts were studied. In this paper, total flavonoids from Buckwheat tea and Sparrow mouth tea were extracted by using ethanol. The influences of four single factors on extraction ratio of total flavonoids were studied, including ethanol concentration, solid-liquid ratio, extract temperature and time. The preferred extraction conditions were ethanol concentration was 50%, solid-liquid ratio was 0.5 ： 40 g · mL^-1 , temperature was 60℃ and extraction time was 2.5 h determined by orthogonal experiment, extraction ratios of flavonoids reached up to 21.64% for Buckwheat tea and 19.41% for Sparrow mouth tea by using spectrophotometer. Antioxidant effects of flavonoids from Buckwheat tea, Sparrow mouth tea and BHT were measured to remove hydroxyl radicals by comparative experiments. It showed that Buckwheat tea and Sparrow mouth tea extracts displayed stronger scavenging effect. Ethanol extractions of total flavonoids from Buckwheat tea and Sparrow mouth tea have been proved to be an effective technique, total flavonoids extracts obtained exhibited stronger scavenging effect on hydroxyl radicals.