红薯叶黄酮分离纯化工艺及抗氧化性研究

Extraction, Purification and Antioxidation of Total Flavonoids from Sweet Potato Leaves

本实验以红薯叶为原料,研究了黄酮类化合物分离纯化工艺,并研究了粗提物与纯化产物对羟基自由基、1,1-二苯基-2-苦基肼自由基(OPPH·)的清除作用。结果表明,红薯叶黄酮最佳提取工艺为60%乙醇水溶液90℃回流提取60min,料液比1:40,粗提物中总黄酮含量为101.3mg/g。提取液用HPD500大孔树脂进行纯化效果好,最佳纯化工艺为:吸附条件:上样原料液黄酮含量1.8mg/ml,pH3上样流速为3BV/h;洗脱条件:50%乙醇、流速3BV/h,流量4BV,在此条件下,纯化产品黄酮含量为488.7mg/g;粗提物与纯化产物均具有对自由基的清除作用,是一种有效的天然抗氧化剂新资源。

Except that few sweet potato leaves are taken as edible food or livestock feed, most of them that contain large amounts of bioactive flavonoids are discarded, which leads to a great waste of available resource. In the present study total flavonoids were extracted from sweet potato leaves using ethanol and purified using macroporous adsorption resin. The extraction and purification procedures were optimized by orthogonal array design and one-factor-at-a-time methods, respectively. Additionally, antioxidant properties of the purified total flavonoids were evaluated by assaying their · OH and DPPH · scavenging activities. The optimal extraction conditions were as follows： ethanol concentration 60%, material/liquid 1 ：40, and temperature 90 ℃ for a thermal refluxing extraction duration of 60 n-fin, and 1 g of the crude extract obtained under such conditions contained 101.3 mg of total flavonoids. The optimal purification parameters using macroporous resin HPD 500 whose adsorption and desorption performance was superior to those of other resins including AB-8, NKA-9, HPD 600 and HPD 450 were as follows： sample concentration 1.8 mg/ml, pH 3, and sample flow rate 3 BV/h; taking 50% ethanol as eluent, eluent flux 3 BV/h, and eluent quantity 4 BV, and the content of total flavonoids in the purified extract was 488.7 mg/g. Both of the crude extract and the purified product displayed a good scavenging activity to · OH and DPPH· .