红枣三萜酸大孔吸附树脂纯化特性及其抗氧化活性研究
Study on triterpenic acids purification from jujube by macroporous resins and its antioxidant activity
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摘要: 对红枣三萜酸的大孔吸附树脂纯化特性和抗氧化活性进行了研究。通过比较D101、AB-8、X-5三种大孔吸附树脂对红枣三萜酸的静态吸附和解吸特性,确定出D101大孔吸附树脂为最佳纯化树脂,进一步研究了D101大孔吸附树脂对红枣三萜酸的吸附等温线、动力学特征,并通过动态吸附解吸实验确定了最佳纯化条件。结果表明:D101大孔吸附树脂对红枣三萜酸具有良好的吸附和解吸性能,且其吸附过程符合准二级速率方程,吸附过程由多种扩散过程控制,其中薄膜扩散为主要扩散方式,吸附量随温度的升高而增大,吸附等温线方程符合Freundlich模型。D101大孔吸附树脂纯化红枣三萜酸的工艺条件为:上样体积7 BV,上样p H为7,洗脱剂为95%乙醇,洗脱剂p H为11,洗脱剂体积为5 BV。在此条件下得到的红枣三萜酸纯度由49%提高至78%。抗氧化活性实验结果表明红枣三萜酸经纯化后清除ABTS+·与·OH的能力均有提高,而清除DPPH·的能力有所降低。Abstract: The purification characteristics by macroporous resin and antioxidant activity of triterpenic acids from jujube was evaluated in this study. D101 was optimized from 3 types of macroporous resins ( D101, AB-8, X-5) for triterpenic acids purification by static adsorption-desorption experiments, and the related adsorption isotherm, adsorption kinetics and the optimal purification conditions was also investigated. The results showed that D101 macroporous resin presented good capabilities of adsorption and desorption of triterpenic acids from jujube, and the kinetics fitted the pseudo-second-order rate equation and its equilibrium adsorption data for triterpenic acids was accordance with Freundlich adsorption isothermal equation.Furthermore, the adsorption capacity was increased with higher temperature.The optimal purification condition was as follows: 7 BV of sample solution ( p H7) and then 5 BV of ethanol solution ( 95%, p H11) as eluent. Under this condition, the purity of triterpenic acids was increased from 49% to 78%. Moreover, the ability of triterpenic acids from jujube to scavenge ABTS+·and·OH was increased, while the ability to scavenge DPPH·was decreased after purification.