新型花色苷衍生物家族的分子结构与呈色的稳定性机制及其功效评价

Anthocyanins are one class of water-soluble polyphenolic pigments widely present in plant kingdom, which possess important bioactivities and physiological functions and potential prospect for applications, however, the problems resulting from structural stability of anthocyanins are the key factors limiting their applications and popularization as well as the substitution for synthetic pigments. Pyranoanthocyanins are new anthocyanin derivatives discovered in aged fruit wines by the present applicant and others in recent years. Based on the formation mechanisms and cycloaddition reaction patterns of pyranoanthocyanins, which had been confirmed in our previous studies, and taking into account the unknown status on the relationships between the structural features and functional properties and bioactivities anthocyanin derivatives, the project is proposed to make preparations of different families of pyranoanthocyanins derivatives by taking the advantage of the electrophilic and nucleophilic reactivity between anthocyanins and intermediates during sugar fermentation and other natural phenolic compounds and by optimizing reaction conditions, which are then investigated in terms of characterization of CIELab parameters, storage stability (degradation dynamics, degradation pathways and mechanism), chromatic stability of cloring wheat gluten and starch,and antioxidant activities as well. The stabilization mechanisms and intrinsic relationships between the chemical, spatial structures of pyranoanthocyanin derivatives and their chromatic and functional stabilities will be analyzed by the establishment of a quantitative structural-activity relationship model which is based on the NMR data and molecular mechanics calculation and simulation for structural characterization, and the toxicological safety will also be assessed for high stable pyranoanthocyanins. The project will provide new approaches to the stabilization techniques of such functional natural pigments as anthocyanins and scientific foundations for deeply developing their applications during product processing and storage periods.

花色苷是植物中普遍存在的一类水溶性酚类色素，具有重要生物活性和生理功能及良好应用前景，但其本身结构稳定性问题是制约花色苷的应用推广和代替合成色素进程的关键。吡喃花色苷是申请者等发现于陈酿果酒中的新型花色苷衍生物。本项目借鉴申请者已证实其形成机制与环加合反应规律最新成果，针对结构特征与功能性质及活性的关系研究缺乏现状，利用花色苷与糖酵解产物及其他天然酚类物质的亲核亲电反应活性并经条件优化制备不同吡喃花色苷衍生物家族，系统研究吡喃花色苷CIELab颜色空间表征、贮藏稳定性（降解动力学、途径和机制）、对面筋蛋白和淀粉着色稳定性及抗氧化活性；结合NMR表征及分子力学计算与模拟建立定量构效关系模型，重点分析吡喃花色苷分子的化学、空间结构影响其色泽和功能稳定性的机理及内在关系，评价高稳定性吡喃花色苷的毒理学安全性，为此类功能性天然色素的稳定化技术研究及其在加工贮藏中深度应用开发提供新的思路和科学基础。

花色苷是植物中普遍存在的一类水溶性酚类色素，具有重要生物活性和生理功能及良好应用前景，但其结构稳定性问题是制约花色苷应用推广和替代合成色素进程的重要因素。基于花色苷的亲核亲电反应活性本项目研究了不同家族花色苷衍生物的高效制备与分离纯化方法、结构鉴定以及表征。研究了新型衍生物的颜色表征、色泽及漂白稳定性、与蛋白相互作用及着色稳定性、贮藏稳定性及其体外细胞抗氧化、抑制增殖及吸收转运等活性评价和急毒安全性评价。分析比较花色苷自身及衍生物分子的化学结构与其呈色特征、稳定性和抗氧化活性等之间关系，探讨吡喃环影响其结构与色泽稳定性的机制。本课题同时研究了新型花色苷蛋白复合物的结构表征与其稳定性，以及花色苷应用在亲水和疏水体系中的包埋稳定性。结果表明，葡萄等植物花色苷与有机酮类或苯丙烯酸类物质在适宜溶液体系经水合或微氧化等反应步骤生成不同系列衍生物。经优化制备分离纯化条件得到产物纯度均超过95%。通过摩尔消光系数、色谱-质谱或核磁光谱与计算、荧光光谱等表征其结构，为花色苷衍生物功能特性和活性评价提供样品基础。花色苷及其衍生物在酸中性范围和不同介质体系中的颜色表征参数结果表明衍生物色泽稳定性、贮藏稳定性等均高于原花色苷前体；热及光降解动力学与半衰期结果表明花色苷衍生物的结构稳定性大大提高。自由基清除及抗细胞氧化损伤的研究结果表明，不同结构花色苷衍生物均具有较强细胞抗氧化活性且呈一定浓度依赖性。急性毒性实验结果表明花色苷衍生物为实际无毒化合物。吡喃酮型花色苷衍生物的抗氧化活性、抑制肿瘤细胞增殖活性及胃壁细胞单层膜中的转运吸收效率均高于前体花色苷及其他结构花色苷衍生物。表明除花色苷B环取代基结构和母环连接糖基外，衍生物第四个吡喃D环及其连接取代基，即吡喃环酮基电子云与π电子云平行共享扩大了其形成的共轭体系，增强此类物质的结构稳定性，影响其色泽稳定性与生物活性，为花色苷的稳定化技术研究提供了思路。