虾青素/环糊精超分子体系的主客体识别机理研究

Astaxanthin is a kind of carotenoids which has stronger biological activity than most of others. However, the application of astaxanthin was limited due to the low water solubility and poor stability. Our previous research showed that the problems should be partly solved by included astaxanthin into the cavity of hydroxypropyl-β-cyclodextrins. Nevertheless, the inclusion rate of the astaxanthin/hydroxypropyl-β-cyclodextrins inclusion complexes was low and the complexes easily assembled in water. The phenomena cannot be explained by the existing inclusion theory which based on the character of cyclodextrins. Therefore, this study will focus on the inclusion behavior between astaxanthin and cyclodextrins and its derivatives which have different structures and cavity sizes. Spectrum analysis technology will be applied to characterize the prepared inclusion complexes. Effect of the inclusion actions on the water solubility, stability and antioxidative activity of astaxanthin will be analysed. The inclusion law between cyclodextrins and astaxanthin will be revealed through structure-activity analysis method combined with the experimental results and quantitative parameters. Furthermore, the effect of the inclusion will be enhanced and the recognition mechanism of this supramolecular system will be revealed based on the three-dimensional inclusion model obtained by structure optimization method of quantum chemistry. This study should supplement the existing theory of cyclodextrins supramolecular system, guild the molecular design of cyclodextrins derivatives, and promote the application of astaxanthin in functional food and medicine.

虾青素是类胡萝卜素中生理活性较强的一种，但其水溶性低、稳定性差的缺点限制了其在功能性食品和医药领域的应用。本课题组的前期研究表明利用羟丙基-β-环糊精与虾青素形成包合物的方法可部分解决该问题，但还存在包合率低、水中易凝聚等现象。而现有的以环糊精为主体的包合理论在解释羟丙基-β-环糊精与虾青素间的以上包合现象时也比较困难。有鉴于此，本课题拟研究具有不同结构与孔径的典型环糊精及其衍生物与虾青素间的包合行为。运用波谱分析技术表征所得各类包合物，分析包合作用对虾青素水溶性、稳定性及抗氧化活性的影响。结合实验结果和量化参数，运用构效分析方法揭示环糊精与虾青素间的包合规律，并采用量子化学结构优化法获得二者的三维包合模型，以期提升包合效果并揭示该超分子体系的主客体识别机理。本课题对于补充现有的环糊精超分子体系理论，指导环糊精衍生物的分子设计，促进虾青素在功能性食品和医药中的广泛应用具有重要意义。

虾青素是一种抗氧化活性较强的类胡萝卜素，具有着色、提高免疫力等功效，但其水溶性低、稳定性差的缺点限制了其在功能性食品和医药领域的应用。采用以环糊精为主体的包埋技术有望解决上述问题。有鉴于此，本课题研究了具有不同结构与孔径的典型环糊精及其衍生物与虾青素间的包合行为。通过正交实验对虾青素/环糊精包合物制备工艺进行了优化，通过相溶解度法对环糊精与虾青素的平衡常数进行测试，顺序为：HP-β-CD >γ-CD >β-CD >M-β-CD >α-CD。通过紫外、红外、X-衍射、热分析和核磁共振确证了包合物的形成，并判断虾青素的端部进入环糊精空腔内。对虾青素/HP-β-CD包合物的稳定性和抗氧化活性进行了研究，发现包合能提高虾青素的稳定性，对部分抗氧化活性有所提高，羟基自由基消除能力稍有降低。通过分子结构优化和量子化学分析方法，结合实验表征结果，归纳得出结合能是二者包埋稳定性的主要量化参数，虾青素易与空腔大小适宜，结构合理的环糊精形成稳定包合物，包合时虾青素端部六元环通过C-2,3开口端进入环糊精空腔，先形成1:1包合物，如果存在过量环糊精，会对虾青素另一端进行包埋，形成1:2包合物。本课题还对与虾青素结构相近的叶黄素的HP-β-CD包合物进行了制备和表征，对虾青素和叶黄素与HP-β-CD包合物在食品中的应用进行了初步探索。本课题阐明了虾青素与环糊精包埋的机理，对于类似环糊精主客体包合物的设计和制备具有借鉴意义，有助于促进功能性食品的开发和利用。