Abstract
The current study investigates the correlation between biological
activity and physicochemical properties of a few specific estradiol
isomers. Theoretical studies on the physicochemical properties of
estradiol isomers were performed using different quantum mechanical
methods. The computational methods used in this study include the
Density Functional Theory (DFT) method, the Hartree-Fock (HF) method and
Semi-empirical (AM1) method. Some physicochemical properties such as
dipole moment, molecular weight, the energy of the highest occupied
molecular orbital (E HOMO), the energy of the lowest unoccupied
molecular orbital (E LUMO), polarizability, the octanol-water partition
coefficient (Log P), polar surface area (PSA) the number of hydrogen
bond donors (HBDs) and the number of hydrogen bond acceptors (HBAs), the
surface area, volume of the molecule, and ovality are calculated for the
isomers. However, only dipole moment values are suitable to identify a
correlation of experimental biological activity of estradiol isomers. To
the best of our knowledge, this is the first report on the relationships
between dipole moment and biological activities of estradiol isomers. It
is observed that the active compound has a significantly higher dipole
moment value compared to the inactive compound. We have also analyzed
the geometrical and graphical models of these isomers and related
compounds to evaluate the differences in the molecular charge
distributions.