大花旋覆花内酯抗肿瘤衍生物合成、构效关系和作用机制研究

Natural active products play a highly significant role in the development of many areas including medicine and agriculture. To obtain higher active lead drugs, structural modification of natural active compounds is now still one of the main ways in the drug discovery and development process..1-O-acetylbritannilactone (ABL) isolated from compositae Inula species is a sesquiterpene lactone. We found that ABL has high content in Inula britannica, and had shown moderate antitumor activities against NCI H460, HeLa and HepG2 cells. In this subject, several series of derivatives with ABL as the lead compound will be designed and semisynthesized on the 1-acetyl, 6-hydroxyl and 13-exocyclic double bond of ABL by acylation, nucleophilic addition and Heck coupling reactions, respectively. In addition, the structure of ABL derivatives will be elucidated by modern spectral analysis, and their antitumor activities will be investigated through cytotoxic activity screening, and their structure-activity relationships (SAR) will be analyzed, so as to find new lead compounds with high activity and low toxicity. Moreover, the primary antitumor mechanisms will be also discussed using molecular biology techniques including apoptosis and cell cycle assays. These data will provide theoretical and experimental evidences of chemistry and pharmacology for the research of new antitumor drugs.

天然活性物质在医药和农业等领域具有重要的地位。对天然活性化合物作进一步的结构改造或修饰，使其成为更高活性的先导药物，是当今新药创制的主要途径之一。.1-O-乙酰基大花旋覆花内酯(ABL)是菊科旋覆花属植物中一个具有抗肿瘤药理活性的倍半萜类天然产物。前期细胞毒活性结果表明，ABL对三株人癌细胞（NCI H460、HeLa和HepG2）增殖具有中等抑制活性。本项目以ABL为先导化合物，分别从1-位乙酰基，6-位羟基和13-位环外双键三个位置进行结构修饰，通过酰基化、亲核加成和Heck偶联等反应半合成一系列衍生物，运用现代波谱等技术对其结构进行归属和表征，借助细胞毒活性筛选实验分析其构效关系，以期发现活性高、毒性低的新先导化合物，进而采用细胞凋亡和细胞周期干预等实验探讨高活性化合物的抗肿瘤作用机制，为新型抗肿瘤药物研究提供化学和药理学基础数据和理论依据。

本项目以天然活性倍半萜1-O-乙酰基大花旋覆花内酯（ABL）为起始化合物，通过多样性合成策略（DOS）构建了这类倍半萜内酯化合物库，得到了65个化合物，64个为新化合物。体外抗癌构效关系实验结果表明：1) 6-羟基的酯化可显著提高其活性，其中当酯基饱和脂肪链数为12个碳时，对人结肠癌HCT116细胞的IC50值最小，活性接近于阳性抗癌药物依托泊苷和5-氟尿嘧啶；2) A环14-位杂原子的引入可显著提高活性，表现出了潜在的可修饰性；3) 6-羟基的氧化和醚化，13-亚甲基的偶联和Michael加成衍生物以及A环9-位接入三唑等衍生物对提高细胞毒活性未有显著影响。进一步的抗癌机制研究发现, 高活性衍生物可诱导细胞凋亡-双染晚期凋亡、procaspase-3和PARP蛋白的磷酸化，其诱导凋亡的机制可能是p53依赖性的，此外，该化合物可阻滞细胞周期在G2/M期。这一结果为新型基于倍半萜天然药物分子的发展提供基础数据和理论依据。在该项目的资助下，已发表SCI论文4篇，正在整理投稿论文2篇；协助培养博士研究生1名，硕士生2人；参加国内学术会议2次。