Novel ZE-isomerism descriptors derived from molecular topology and their application to QSAR analysis.

We introduce several series of novel ZE-isomerism descriptors derived directly from two-dimensional molecular topology. These descriptors make use of a quantity named ZE-isomerism correction, which is added to the vertex degrees of atoms connected by double bonds in Z and E configurations. This approach is similar to the one described previously for topological chirality descriptors (Golbraikh, A., et al. J. Chem. Inf. Comput. Sci. 2001, 41, 147-158). The ZE-isomerism descriptors include modified molecular connectivity indices, overall Zagreb indices, extended connectivity, overall connectivity, and topological charge indices. They can be either real or complex numbers. Mathematical properties of different subgroups of ZE-isomerism descriptors are discussed. These descriptors circumvent the inability of conventional topological indices to distinguish between Z and E isomers. The applicability of ZE-isomerism descriptors to QSAR analysis is demonstrated in the studies of a series of 131 anticancer agents inhibiting tubulin polymerization.