柘木多酚和氧化白藜芦醇的制备与其抗氧化活性研究

Preparation and Antioxidant Activities of Polyphenols and Oxyresveratrol in Stems of Cudrania tricuspidata

目的:对柘木多酚及其中主要成分进行制备和抗氧化活性研究,为其开发利用提供参考。方法:柘木茎的75%乙醇提取物采用AB-8大孔树脂精制,对其中的主成分进行分离鉴定和HPLC含量测定,采用DPPH和ABTS法测试其抗氧化活性。结果:柘木茎经精制获得柘木多酚CTP-1、CTP-2;从CTP-1进一步分离获得化合物1,经鉴定为氧化白藜芦醇。HPLC分析表明,二者中均主要含有氧化白藜芦醇。抗氧化活性测验结果表明,CTP-1、CTP-2及氧化白藜芦醇对DPPH自由基的半数抑制浓度(IC50)值分别为19. 1、25. 3、11. 2μg·m L^(-1),对ABTS自由基的IC50分别为49. 3、60. 1、29. 7μg·m L^(-1)。结论:柘木多酚具有强抗氧化活性,氧化白藜芦醇是其主要活性成分。

Objective： Polyphenols and key component of Cudrania tricuspidata and their antioxidant capacities were investigated in this study to provide reference data for their potential applications as antioxidant agent in future. Methods： The stems of C. tricuspidata were extracted with 75% ethanol, followed by AB-8 macroporous resin purification to give two frac- tions, CTP-1 and CTP-2, respectively. Key components in CTPs were separated and determined by HPLC. DPPH and ABTS tests were applied to measure their antioxidant activities. Results： Two fractions were thus obtained, and oxyresveratrol（ 1 ）was separated and identified from CTP-1, which was determined to be major ingredient of both CTPs by HPLC. As for antioxidant assay, half inhibition concentrations（ IC50 ）of CTP-1, CTP-2 and oxyresveratrol against DPPH free radicals were 19. 1, 25.3, and 11.2 μg · mL-1, respectively, their IC50 values against ABTS free radicals were 49.3 , 60. 1 and 29. 7 μ ·mL -1 , re- spectively. Conclusion： CTPs possess strong antioxidant capacities, with oxyresveratrol as the major ingredient within them.