大黄素衍生物抗肿瘤活性的神经网络模型

目的:建立大黄素衍生物抗肿瘤活性的神经网络模型。方法:采用量子化学的AM1算法,计算了12个大黄素衍生物分子的结构参数,并用逐步回归分析,筛选结构参数。结果:利用筛选后的结构参数,建立大黄素衍生物抗肿瘤活性的神经网络模型。结论:抽一法交叉预报结果表明,本文建立的大黄素衍生物抗肿瘤活性的神经网络模型,预报结果可靠,具有一定的应用价值。     

支持向量机回归方法用于黄酮类化合物醛糖还原酶抑制活性的QSAR研究

用支持向量机回归(SVR)方法研究了48个黄酮类化合物醛糖还原酶抑制活性的定量构效关系。建模过程中利用留一法交叉验证(LOOCV)优化了核函数的类型、惩罚系数C和不敏感函数ε.所建模型最终采用了227个变量中的7个:dChivps9, ESHaaCH,EsssCH2,n2pag[1,2],degree2,I'3和I'4。所得SVR模型的预测相对误差为0.0622,小于多元线性回归(MLR)和偏最小二乘法(PLS),以及文献报道模型的预测相对误差。     

5′-甲硫腺苷核苷酶抑制剂的QSAR研究

通过构建33个甲硫腺苷(MTA)类似物的化学结构模型,并使用Molconn-Z统计的电子拓扑指数、形状指数和分子连接性指数作为受试化合物分子结构参数,结合多元线性回归(MLR)方法对MTA类似物的抑制活性进行了QSAR研究。所得模型的R和R2adj分别为0.862和0.711,表明该模型具有较好的预测和反映真实情况的能力。模型表明,MTA类似物的抑制活性与其所含硫和氮原子的电子拓扑指数以及分子形状指数相关,这为预测其他类似物的活性和设计新的抑制剂提供了理论依据。     

A topological sub-structural approach to the mutagenic activity in dental monomers. 2. Cycloaliphatic epoxides

The topological sub-structural molecular design (TOPS-MODE) approach has been introduced for the study of mutagenic properties. The mutagenicity of 15 dental monomers was studied with this approach obtaining a good quantitative structure-toxicity model. For purposes of comparison, we employed seven different weights in the diagonal entries of the bond matrix in order to select the best TOPS-MODE model. In addition, our best model was compared with a model previously reported in the literature, and proved to be superior. Finally, the TOPS-MODE approach was used to derive the contribution of different fragments to the mutagenicity of all the compounds studied.     

A topological sub-structural approach to the mutagenic activity in dental monomers. 3. Heterogeneous set of compounds

The topological sub-structural molecular design (TOPS-MODE) approach has been applied to the study of mutagenic properties in a heterogeneous set of dental monomers. A model able to describe close to 90% of the experimental variance in the values for mutagenic activity of 41 dental monomers through genetic algorithm was developed with the use of the mentioned approach. Also, a study for the determination of the optimal number of variables in the equation and potential outliers was carried out. Finally, the TOPS-MODE approach was used to derive the contribution of different fragments to the mutagenic activity.     

香豆素磺酰脲类化合物降血糖活性的定量构效关系研究

目的：研究新型香豆素磺酰脲化合物降血糖作用与化学结构之间的关系,为进一步设计合成该类化合物提供理论依据。方法：选择10个降血糖活性较强的化合物,利用MM!分子力学和CNDO／2量子化学方法计算有关结构参数并进行定量构效关系研究。结果：香豆素-6-磺酰脲类化合物的降血糖活性与磺酰脲基与母核的二面角呈负相关;与母核1位碳原子LUMO轨道本征矢量负相关;与化合物分子的偶极矩正相关。结论：推测分子中7-位甲基的引入不利于磺酰脲基与香豆素母环共平面,降低化合物的降血糖活性;香豆素母环上引入供电子基团不利于增加降血糖活性,可尝试引入吸电子基团;化合物分子偶极矩的增加对降血糖活性有利。