樫木属植物中新型PTP1B抑制剂的发现及其分子作用机制研究

PTP1B is closely related to insulin resistance, which runs through the whole process of diabetes. Because of the negative charge group in structure, the electivity and cell membrane permeability of the existing PTP1B inhibitors were poor. Our team showed that seven new diterpenoids from Dysoxylum lukii, which structures were different from those of the existing PTP1B inhibitors, possess the PTP1B inhibitory activity and selectivity for the first time. These results suggested that the novel leading compounds inhibiting PTP1B will be found form the plants of Dysoxylum genus. So, on the base of our previous works, in order to establish a library of diversiform structure compounds, the diterpenoids from three plants of Dysoxylum genus will be systematic separated and high-content compounds will be derived through chemical synthesis. The works screening bioactivity compounds will be carried out with two models and the better activity compounds will be re-assay with the rat model. The kinetic and thermodynamic parameters, the binding site, the binding mode, and the binding processes of the active compounds were studied by means of simulation calculation and experimental verification. When all studies are completed, a new structure, high selectivity, and clear mechanism leading compound inhibiting PTP1B will be found in this project. Our research results will lay the foundation for the creation of new PTP1B inhibitors with independent intellectual property rights.

胰岛素抵抗贯穿糖尿病发展的全过程，蛋白酪氨酸磷酸酶1B（PTP1B）与胰岛素抵抗密切相关。现有PTP1B抑制剂多为带有强负电荷的类肽类，选择性和膜通透性差。本项目首次从多脉樫木中分离出7个具有PTP1B抑制活性的新二萜类成分，其结构与以往PTP1B抑制剂的相差较大，且具有选择性。因此樫木属植物可能是发现新型PTP1B抑制剂的重要资源。本项目拟开展以下探索：1）对前期初步判断二萜含量丰富的三种樫木属植物进行分离，并对量丰化合物进行结构改造，合成系列衍生物，建立化合物库；2）从分子-细胞-动物三个层次，依次递推，筛选出高活性化合物并研究其选择性；3）将模拟计算与实验验证相结合，研究强活性化合物与PTP1B结合位点、结合方式及作用力，探讨作用机制。以上研究不仅有望发现选择性高、作用机制明确的抑制PTP1B的先导化合物，更为创制具有自主知识产权的新型PTP1B抑制剂奠定基础。

胰岛素抵抗贯穿糖尿病发展的全过程，蛋白酪氨酸磷酸酶1B（PTP1B）与胰岛素抵抗密切相关。本课题开展了4种樫木属植物的化学研究，评价了它们对PTP1B抑制活性，并探讨了3个化合物作用行为。取得如下进展： (1) 分离得到化合物99个，化合物结构主要为二萜、倍半萜、三萜，新化合物17个，新化合物包括结构罕见的2，3位开环，然后2位降解的甘遂烷三萜化合物和罕见具有过氧桥的prenyleudesmane二萜类化合物，并推导了它们的生物合成假说。其次大部分化合物均从相应植物中首次得到，为这些植物的开发提供研究基础。 (2) 以p-NPP为底物的比色法模型评价库内各单体化合物体外抑制PTP1B和TCPTP的效果，发现20个化合物具有抑制PTP1B活性，其中二萜6个、倍半萜4个、三萜10个；发现2个倍半萜和1个二萜具有选择性抑制PTP1B活性。 (3) 两种胰岛素抵抗细胞模型的活性验证有选择性抑制PTP1B活性的3个化合物具有促进葡萄糖消耗作用。（4）采用DOCK6、Amber 20、荧光光谱等方法研究了3个化合物与PTP1B结合的行为，确定了结合位点和抑制行为。上述结果为针对PTP1B进行药物设计提供了重要的活性化合物及理论基础。