酚类菊糖衍生物的制备及抗氧化活性

Synthesis and Antioxidant Properties of Phenolic-Functionalized Inulin Derivatives

以菊糖为原料,通过改性提高菊糖的抗氧化活性,研究其结构与抗氧化活性的关系。利用溴代、亲核取代和缩合三步反应制备酚类菊糖衍生物,通过活性基团的引入达到提高菊糖抗氧化活性的目的。结果表明,菊糖衍生物的抗氧化活性,包括还原能力、Fe^(2+)螯合能力和对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基、羟自由基和超氧阴离子自由基3种自由基的清除活性都较菊糖显著提高,含有双酚的菊糖衍生物(化合物3C、3D)比含有单酚的菊糖衍生物表现出更强的自由基清除能力。其中含有双酚的菊糖衍生物对DPPH自由基清除能力的半抑制质量浓度(half maximal inhibitory concentration,IC_(50))为0.007 mg/mL,较VE的DPPH自由基清除能力高;化合物3C超氧阴离子自由基清除能力IC_(50)为0.042 mg/mL;化合物3B Fe^(2+)螯合能力IC_(50)达到0.006 mg/mL。同时通过研究电子或质子转移和中间体探讨可能的自由基清除机制。体外细胞毒性实验证实酚类菊糖衍生物有较好的生物相容性,这些结果有助于开发菊糖衍生物在抗氧化剂或自由基清除剂等方面的应用。

In this study,chemical modification was used to enhance the antioxidant properties of inulin and the relationship between the structure and antioxidant activity of the modified inulin was investigated.Phenolic-functionalized inulin derivatives were prepared by sequential bromination,nucleophilic substitution and condensation,improving the antioxidant activity of inulin by the introduction of active groups into the molecule.The antioxidant activity of the inulin derivatives in terms of reducing power,ferrous ion chelating ability,and scavenging activity toward 1,1-diphenyl-2-picrylhydrazyl(DPPH),hydroxyl and superoxide anion radical was significantly stronger than that of inulin.The inulin derivatives with diphenol(component 3C,3D)showed much stronger free radical scavenging capacity than those with monophenol,and had stronger DPPH radical scavenging activity than vitamin E with a half maximal inhibitory concentration(IC_(50))of 0.007 mg/mL.In addition,the IC_(50)for O_(2)^(-)·scavenging activity of component 3C and iron ion chelating capacity of component 3B were 0.042 and 0.006 mg/mL,respectively.Meanwhile,the possible radical scavenging mechanism was explored by studying electron or proton transfer and intermediates.The in vitro cytotoxicity test showed that the inulin derivatives had good biocompatibility.These observations will contribute to the development of inulin derivatives to be applied as antioxidants or free radical scavengers.