皂甙的三维定量构效关系研究

针对目标分子柔性大的特点,在比较分子场分析(CoMFA)方法中采用交叉验证相关系数平方R^2引导的构象选择法。对12个皂甙分子的生物活性进行了三维定量构效关系研究。探讨了几种探针对构效关系结果的影响,并选择了一种较合理的“复合”探针方案。应用该复合探针构建CoMFA模型,发现影响药效的立体场与静电场的贡献分别为40%和40%,其它能量项的贡献为20%。该模型交叉验证的相关系数平方R^2为0.653,非交叉验证的R^2为0.991,方差比F(4,7)值130.195(即置信度99%以上),活性预计的标准偏差与极差比(s/△γ)为4.2%,表明模型具有较好的预测能力。根据该模型,预计在指定位置添加位阻较大的基团活性值提高将会比较明显。

3D-QSAR studies of saponins

In this article, the R^2 guided region selection CoMFA method was used to investigate 12 saponins for their 3D-QSAR. The impact of the probes on the result of CoMFA model is analyzed including some complex probe models. The final result of CoMFA model proved that the contribution to activity from steric field is 40%, and that from electrostatic field is 40%. The cross-validated R^2 of the CoMFA model is 0.653, and the non-crossvalidated R^2 is 0.991. The variance ratio F(4,7) obtained is 130.195 with confidence level above 99%, and the ratio of standard error and extremal length obtained, s/△γ, is 4.2%. These results proved that the CoMFA model has good prediction, and some new compounds with higher activity can be disigned based on it.