大孔树脂纯化沉香叶黄酮工艺优化及纯化前后抗氧化性比较

研究沉香叶黄酮的大孔树脂纯化工艺及其抗氧化性。通过静态和动态实验,考察树脂种类、粗提液浓度、洗脱剂、上样流速、洗脱流速对沉香叶黄酮吸附解吸性能的影响,确定最佳纯化工艺条件;采用羟自由基法、DPPH自由基和ABTS自由基法,比较纯化前后沉香叶黄酮的抗氧化性。结果表明,NKA-9大孔树脂纯化沉香叶黄酮效果最好,最佳条件为:以1.5 mL/min速度将5.0 mg/mL粗提液上柱,用70%(v/v)乙醇以2.0 mg/mL速度洗脱,此条件下沉香叶黄酮纯度提高至76.58%±3.46%。沉香叶黄酮纯化后清除羟自由基、DPPH自由基和ABTS自由基IC₅₀值分别为(0.120±0.008)、(0.016±0.009)、(0.042±0.002)mg/mL,远低于纯化前的(0.300±0.015)、(0.170±0.008)、(0.160±0.009)mg/mL,说明沉香叶黄酮纯化前后均具有较强的抗氧化性,纯化后抗氧化性明显增强。NKA-9大孔树脂适合分离纯化沉香叶黄酮。

Optimization of Purification of Flavonoids from Aloes Leaves with Macroporous Resin and Comparison of Antioxidant Capacity of Crude and Purified Flavonoids

The purification of flavonoids extracted from aloes leaves by macroporous resin and its antioxidant activity were studied. Based on the static and dynamic experiments,the influence of resin type,crude extract concentration,eluent,loading flow rate and elution flow rate on the adsorption and desorption properties of flavonoids from aloes leaves were investigated to determine the optimal purification conditions. Comparison of antioxidant activity of crude and purified flavonoids from aloes leaves was evaluated by three different methods which were hydroxyl,DPPH and ABTS free radical scavenging assay.NKA-9 was the most suitable type of macroporous resin and the optimum conditions were as follows:The optimal purification conditions were as follows:5.0 mg/mL sample concentration was applied to the column at flow rate of 1.5 mg/mL,and 70%(v/v)alcohol was used to elution with eluanting velocity of 2.0 mL/min. Under these conditions,the purity of flavonoid extracted from aloes leaves increased to 76.58%±3.46%. The IC₅₀ of the final purified product for scavenging hydroxyl,DPPH and ABTS and free radicals were(0.120±0.008),(0.016±0.009),(0.042±0.002) mg/mL respectively,they were much lower than the corresponding results which showed(0.300±0.015),(0.170±0.008),(0.160±0.009) mg/mL of crude flavonoids. The results suggested that the flavonoids from aloes leaves revealed strong antioxidant activity before and after purification,and the antioxidant activity was much stronger after purification. NKA-9 macroporous resin was suitable for separation and purification of flavonoids from aloes leaves.