涩柿树皮单宁的纯化及抗氧化活性

Purification and Antioxidant Activity of Tannin from Persimmon Tree Bark

选用超声波法从涩柿树皮中提取单宁,溶剂法、大孔树脂法纯化粗提物,并考察了不同纯度的单宁对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和羟自由基(·OH)的清除作用。结果表明:涩柿树皮单宁的超声波提取率为5.6%;大孔吸附树脂纯化涩柿树皮单宁的最佳工艺参数为:以HPD-500树脂为吸附树脂,上柱流速1.5 m L/min,上样质量浓度1.2 mg/m L;洗脱流速1.5 m L/min,乙醇体积分数60%;粗提物、乙酸乙酯萃取物、大孔树脂纯化物、乙酸乙酯萃余物经大孔树脂纯化后产物、乙酸乙酯萃取物经大孔树脂纯化后产物的纯度分别为5.6%、11.5%、19.4%、47.4%、53.3%;当质量浓度为1 mg/m L时各纯度单宁对DPPH自由基有最大清除率,清除率分别为69.07%、80.19%、92.96%、94.02%、94.05%;清除DPPH自由基的IC50值分别为0.68、0.52、0.13、0.12、0.11 mg/m L;当质量浓度为0.9 mg/m L时各纯度单宁对·OH有最大清除率,清除率分别为43.04%、73.99%、83.00%、94.68%、96.23%。

Tannin in persimmon tree bark was ultrasonically extracted. The crude extract was purified by organic solvent extraction and macroporous resin adsorption. The free radical scavenging activity of tannin samples with different purities was studied using two different systems. The extraction yield of tannin in the crude extract was 5.6%. The optimum conditions for purifying the crude extract with HPD-500 macroporous resin were as follows： a sample containing 1.2 mg/m L tannin was loaded onto the column at a flow rate of 1.5 m L/min and eluted with 60% ethanol at a flow rate of 1.5 m L/min. The purity of the crude extract was 5.6%, which was increased to 19.4% after macroporous resin purification. After ethyl acetate extraction of the crude extract, the extract phase was purified to a purity of 11.5%. After further purification by macroporous resin adsorption, the purity of the raffinate and extract phases was increased to 47.4% and 53.3%, respectively. The crude extract and the resulting purified samples exhibited maximum percentage（69.07%, 92.96%, 80.19%, 94.02%and 94.05%, respectively） of DPPH radical scavenging activity at 1 mg/m L with an IC50 value of 0.68, 0.13, 0.52, 0.12 and 0.11 mg/m L, respectively. The maximum percentage scavenging（43.04%, 83.00%, 73.99%, 94.68% and 96.23%, respectively） of ·OH by the tannin samples with different purities at 0.9 mg/m L was obtained.