【摘要】 为了探讨对DNA及其组份的电荷转移保护机理,继咖啡酸之后研究了另一个羟基肉桂酸衍生物——芥子碱的保护效应。芥子碱也属于苯基取代不饱和羧酸而且它的电子亲和势与咖啡酸非常接近,但其电离电位(ε_HOMO:-11.27eV)却明显低于咖啡酸(ε_HOMO:-11.74eV),因此芥子碱应对DNA呈现更强的保护效应。例如,当DNA—芥子碱二元体系中芥子碱的克分子比明显低于DNA—咖啡酸中咖啡酸的克分子比时低温辐照并测定的ESR波谱以及室温退火后测定的ESR波谱均呈现很强的芥子碱信号,未发现以胸腺嘧啶五位自由基的特征的任何痕迹,说明芥子碱对DNA的保护效应比咖啡酸强。更多还原

【Abstract】 In order to investigate the charge transfer protection mechanism onDNA and dTMP another hydroxy cinnamic acid derivative-sinapine has been studied.Sinapine also belongs to phenyl substituted unsaturated carboxylic acid and its EA（SLEMO: 1. 81 eV） is very close to that of caffeic acid ε_LEMO: 1.79 eV) but its IP（SHOMO:-11. 27 eV） is much lower than that of caffeic acid (ε_HOMO:-11. 74 eV), there-fore in comparision with caffeic acid sinapine exert stronger protection effect on DNA,for example, ESR spectrum from DNA-sinapine with more minor molar ratio of pro-tector to nucleotide of DNA（1:8） than that of DNA-caffeic acid （1:4） revealed thecharacteristic similar to that from sinapine alone irradiated and recorded at 77 K.After annealing at room temperature the ESR pattern changed into that from sinapinealone with clear baseline demonstrating no trace signal from 5-thymyl radical i. e.stronger protective effect by sinapine.更多还原