防治植物病毒病的新型1,3,4-噁二唑衍生物的发现及作用机制初探

Recently, plant viral diseases happened and spread dramatically in our country. Because of the difficulty in preventing and controlling, it has become one of the important reasons for grain reduction and crop economic losses. It was found in the preliminary study that oxadiazole-based derivatives displayed good antiviral activity, which has the potential for further research. Herein, we will systematically design and synthesize oxadiazole-based derivatives to obtain excellent antiviral compounds. We will firstly introduce oxacyclopropane moiety onto the skeleton of oxadiazole, then using different types of nucleophiles to open the cycle to provide the target compounds or crucial intermediates. This lays the foundation for the construction of diversity target structures. All the title compounds will be evaluated against plant viruses. The quantitative structure-activity relationship (QSAR) will be discussed to summarize the structural features of highly active compounds, which will provide a direction for the modification of new compounds. We anticipated that highly bioactive compounds will be discovered, and which will exert the potential for further development. Meanwhile, the action mechanism of highly reactive compounds will be explored to search for potential targets. This proposal will provide some scientific references for new antiviral drugs innovation and the management of plant viral diseases.

近年来，植物病毒病在我国大规模发生并流行，并在全国有进一步扩散蔓延趋势，为害范围广，防治困难，是造成我国粮食减产和农作物经济损失的重要原因之一。申请者课题组前期工作发现噁二唑衍生物表现出了良好抗植物病毒活性，具有进一步研究的潜力。本申请在此基础上拟系统地构建新型噁二唑衍生物，首先在噁二唑骨架上引入环氧乙烷亚结构，然后与不同结构类型的亲核试剂进行开环反应获得目标化合物或关键中间体，为构建多样性目标结构打下基础。所合成的目标化合物进行抗病毒生物活性测试，在此基础上进行定量构效关系分析，建立QSAR模型，总结高效活性化合物的结构特征，进而深入改造和优化目标结构，力争发现活性优异且具有开发潜力的目标化合物。同时，对高活性化合物的作用机制进行初步探索，寻找高活性化合物的潜在靶标，为新抗病毒剂创制和植物病毒病的防治提供科学参考。

按计划开展了各项研究工作，以噁二唑结构为基本骨架，设计合成了多个系列新型1,3,4-噁二唑衍生物，采用半叶枯斑法测试了目标化合物的抗病毒活性，抗烟草花叶病毒（TMV）活体测试结果表明多个目标结构表现出了优异的抗病毒活性，高活性化合物抗TMV活性的EC50值可达到97.4 µg/mL，明显优于商品药剂宁南霉素和病毒唑。基于结构与活性测试结果进行了定量构效关系分析，总结了具备高效抗病毒活性化合物的结构特征，为目标分子结构的深入优化提供了参考。替换噁二唑骨架为天然阿魏酸片段、1,4-戊二烯-3-酮片段等，构建了目标分子的结构多样性，发现了多个新型抗病毒先导结构。同时采用了绿色荧光蛋白（GFP）示踪技术、实时定量聚合酶链反应（qRT-PCR）、蛋白印迹实验（western blotting）及防御酶活性测试实验等探究了高活性化合物的抗病毒机制。上述研究内容与结果为新型抗病毒先导化合物的发掘提供了线索，也为新抗病毒剂农药的研发与创制打下了科学基础。