云南烤烟中新颖的甾醇类化合物及其抗肿瘤活性研究

Natural products, as an important source of antitumor compounds with novel structures and unique action mechanisms, have played an extremely irreplaceable role in the discovery of lead compounds and new drugs. Previous study shows that steroids have significant anti-tumor activity and widely exsit as an important secondary metabolites class of tabacco. Our previous research has led to the isolation of seven new sterol compounds including one new type of C-23 sterol skeleton and a bioactive anti-tumor sterol. Based on this finding, the representative samples will be selected out from the flue-cure tobaccos of different varieties at different places by HPLC analysis and the bioactivity screening of their extract in this project, and the in-depth phytochemical study toward antitumor srerols in tobacco using modern isolation and purification technology will be carried out. As a result, more than eighteen new sterol compounds (incloding 1-3 compounds with new skeletons) will be isolated from these samples, and the compounds with high contents will be enzyme catalyzed and further separated.The antitumor biological activity of these compounds will be carefully screened, and 2-4 compounds with notable antitumor activity will be selected out. These will provide the lead compounds for the development of new anticancer drugs. Furthermore, it will be studied on the antitumor mechanism for some compounds with significant activity and the structure-activity relationships of bioactive compounds as well as the biosynthetic pathways of some novel structures.

天然产物是结构新颖和作用独特的抗肿瘤制剂的重要来源，在新药及新药先导化合物的发现中起着不可替代的作用。研究表明，植物甾醇具有显著的抗肿瘤作用，同时，甾醇是烟草中一类重要的化合物；我们前期研究从云南烤烟乙酸乙酯萃取部位正相层析氯仿段分离得到7个新甾醇化合物，其中包括一种C-23骨架的新类型甾醇和一个具有显著抗肿瘤活性的新甾醇。基于此，本项目将采集不同产地、品种的云南烤烟，通过HPLC分析结合提取物活性筛选的方法从中选出代表性样品，用现代分离技术对样品中抗肿瘤活性甾醇进行深入研究。预期将从2个选定样品中发现18个以上的新甾醇类化合物，包括1-3种新骨架，并对高含量的甾醇单体通过生物转化法进行结构修饰和改造，筛选出2-4活性显著的化合物，为新型抗肿瘤制剂开发提供先导化合物。此外，项目还将对部分活性好的甾醇类结构进行抗肿瘤机理研究，并探讨活性甾醇的构效关系以及结构新颖甾醇的生源途径。

项目组紧扣计划任务书要求，应用植物化学及生物转发研究手段，对云产烤烟样品中的甾醇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成分筛选。项目组采集了不同产地、品种的云产烤烟20种，并从中筛选出2种甾醇含量丰富样品，累积分离鉴定化合物93个，其中甾醇类化合物25个(包9个新甾醇类化合物、倍半萜类化合物23个（新化合物8个）、酚类化合物31个（新化合物14个）、生育酚类2个、三萜2个。项目组完成了32个化合物的细胞毒毒活性（25个甾醇）筛选，发现了8个具有一定细胞毒活性的甾醇，对代表性甾醇类成分的作用机理进行初步研究。对60个化合物（甾醇9个、倍半萜23个、酚类31个）的抗烟草花叶病毒活性进行筛选，从中发现了多个具有显著抗烟草花叶病毒活性的化合物。项目成果共在SCI收录期刊发表研究论文15篇，所有发表论文均标准了基金资助号；还获得了3件发明专利授权。总体上，超额完成了计划任务书规定的研究内容。