【作者】 杨汝婷；

【导师】 周波；

【作者基本信息】 兰州大学 ， 有机化学， 2010， 硕士

【摘要】 羟基肉桂酸类化合物如阿魏酸(FA)、咖啡酸(CA)和芥子酸(SA)广泛存在于植物和果蔬类食品中,具有重要的生物和药理活性,包括抗氧化活性。它们在植物体内经历酶催化的氧化偶联生成相应的二聚物和低聚物。研究发现这些低聚物也具有重要的生物活性。鉴于这些低聚物在植物体内含量较低,且化学仿生合成及生物活性研究较少。因此,本文采用各种无机单电子氧化剂(Ag2O、AgOAc、CuSO4, FeCl3和K3[Fe(CN)6]),研究了羟基肉桂酸在不同条件下的氧化偶联产物。结果表明：化合物的单体结构、无机单电子氧化剂的种类和溶剂对氧化反应有着显著的影响。在Ag2O/CH3OH体系中,可以以较高的产率得到FA和SA的8-8’-双内酯二聚物(8-8’-DiFA和8-8’-DiSA)和一个新的FA三聚物(8-O-4/8-O-4-Tri-FA);而在CuSO4的CH3CN-H2O (v:v=1:2)体系中,可以以高产率得到CA的二聚物(8-8’-DiCA)。我们进一步测定了羟基肉桂酸类化合物及其氧化偶联产物清除DPPH·的能力。发现具有邻二羟基结构的化合物CA和其二聚物8-8’-DiCA具有更高的清除DPPH·的活性。有趣的是,咖啡酸的二聚物8-8’-DiCA比其单体CA活性更高,说明CA的氧化偶联进一步提高了母体分子清除自由基的能力。这些结果为设计新型的抗氧化剂药物分子提供了信息。更多还原

【Abstract】 Hydroxycinnamic acid derivatives (HCAs), including ferulic acid (FA) (1), sinapic acid (SA) (2) and caffeic acid (CA) (3), are widely distributed in the plant kingdom. These compounds have been attracted considerable attention due to their various biological and pharmacological activities including antioxidative activity. It is well known that the monomeric HCAs can undergo enzymatic catalyzed oxidative cross-coupling leading to the corresponding dehydrodimers, trimers and even higher oligomers in plants. However, there have been only few reports about biological activity and oxidative cross-coupling products via chem-biomimetic synthesis of the related oligomers.In this thesis, a nonenzymatic and efficient method for the preparation of the three dilactones (8-8’-DiFA,8-8’-DiSA,8-8’-DiCA)(?) and a new FA trimer (8-O-4/8-O-4-Tri-FA) as described. It was found that 8-8’-DiFA,8-8’-DiSA and Tri-FA can be synthesized with high yields by the reaction of the corresponding monomers with Ag2O in methanol system. Otherwise,8-8’-DiCA can be efficiently obtained with CUSO4 in acetonitrile/water(v/v=1:2) system. Furthermore, the radical-scavenging activities of Hydroxycinnamic acid derivatives and their oligomers were also evaluated by using DPPH·method. It was revealed that CA and 8-8’-DiCA bearing o-dihydroxyl groups exhibited significantly higher radical-scavenging activity than those bearing no such groups, and 8-8’-DiCA was the most active one among the compounds examined.更多还原