云南烟草中新颖的倍半萜类化合物及其抗病毒活性研究

Sesquiterpenes are an important kind of phytoalexins in tobacco. The tobacco plant would make a defense against the virus and generated the antiviral sesquiterpenes when they inffected with the tobacco mosaic virus（TMV）. Our previous study found that sesquiterpenes in tobacco were very rich, and the tobacco varieties with TMV resisttance contanined more sesquiterpenes both in types and contents than those without TMV resistance. Thus, an in-depth study on targeted selection of TMV resistant varieties can be carried out to find out more sesquiterpene with anti-TMV activities. Based on this, this project will have a targeted selection of high antiviral tobacco from Yunnan's rich resources of tobacco varieties and the chemical constitutions of the selected samples will be carefully studied by modern separation technology. As a result, more than thirty new sesquiterpenes (including 3-5 compounds with new skeletons) will be isolated from these samples. The anti-TMV activity of the isolated compounds will be carefully screened, and 3-5 compounds with notable antiviral activities will be selected out. These will provide the leading compounds for the development of efficient and safe virus inhibitor to plants diseases. Furthermore, the antiviral mechanisms of some compounds with prominent activity will be studied; the mechanisms of antiviral activity, the structure - activity relationships, the biosynthetic pathways of the compounds will be discussed as well; And the chemical defense mechanism of tobacco plant under the stress of tobacco mosaic virus will also be preliminary clarified in this project.

倍半萜类化合物是烟草中的一类重要植物保卫素，当烟草受到花叶病毒浸染时，会产生具有抗病毒活性的倍半萜对病毒做出防御。我们前期研究发现烟草中倍半萜类化合物非常丰富，而且烟草植株中倍半萜类化合物的种类和含量和烟草对花叶病的抗性有关，即抗花叶病毒烟草品种中倍半萜类的种类和含量都比不抗病毒的品种高，可通有针对性的选择对花叶病抵抗力高的品种进行深入研究，以期发现更多具有抗病毒活性的倍半萜。基于这一发现，本项目将有针对性的从云南丰富的烟草资源中选择高抗病毒的烟草品种，用现代分离技术对样品中倍半萜类化合物进行深入研究。预期将从3个选定样品中发现30个以上的新倍半萜类化合物，包括3-5个新骨架，并筛选出3-5个活性显著的化合物结构，为高效、安全的植物病毒抑制剂开发提供先导化合物。同时，项目还将对部分活性好的倍半萜进行抗病毒机理研究，探讨其构效关系和生源途径，并初步阐明烟草在花叶病毒胁迫下的化学防御机制。

项目组紧扣计划任务书要求，应用植物化学研究手段，对云产烤烟样品中的倍半萜类化合物及其生物活性进行详细研究。此外，扩展性的对云产烤烟中的其它类型次生代谢产物进行系统分离；对分离得到的部分化合物进行抗烟草花叶病毒活性及细胞毒活性筛选。项目累积从不同产地的烟草植物中分离到倍半萜类化合物30个（新化合物15个）、倍半萜类衍生物39个（新化合物20个），上述倍半萜类化合物共计69个，新化合物35个，新骨架类型6个；此外，项目组还分离得到吲哚生物碱化合物类6个（新化合物5个）、异香豆素类化合物6个（新化合物2个）、新的木脂素2个，所有化合物均通过核磁共振、质谱、红外、紫外光谱等波谱技术对结构进行准确鉴定。项目组针对上述提取量符合活性筛选要求的化合物进行了抗烟草花叶病毒活性和细胞毒活性筛选，累计完成了46个倍半萜类化合物的抗烟草花叶活性筛选，完成了30个倍半萜类化合物的细胞毒活性筛选；针对4个异香豆素和5个生物碱类化合物均进行了抗烟草花叶病毒活性筛选，4个生物碱类化合物进行了细胞毒活性筛选；发现了14个抗烟草花叶病毒活性显著的化合物，对代表性倍半萜类成分的作用机理进行初步研究和构效关系总结；发现10个具有中等到弱的细胞毒活性化合物。完成的项目成果累计在SCI收录期刊发表SCI研究论文13篇，10件发明专利获得授权。