A Computational Modeling of the Structure, Frontier Molecular Orbital (FMO) Analysis, and Global and Local Reactive Descriptors of a Phytochemical ‘Coumestrol’

Abstract

Coumestrol is an estrogenic isoflavonoid which belongs to the class of phytochemicals known as coumestans, with interesting therapeutic applications such as antioxidant and anticancer properties. Coumestrol is widely spread in leguminous plants, alfalfa, ladino clover, strawberry, soya bean, sprouts, pea silage, and beans. The structure of coumestrol is closely resembles to the (E)-4,4’-dihydroxystilbene derivatives, which have promising pharmacological activity, and is responsible for the estrogenic activity of coumestrol. The present work, deals with the computational investigation of the structural analysis of coumestrol, by using M06 as level of theory and 6–31++G (d, p) as basis set in Gaussian 09 software package. The stable conformer of coumestrol has been identified through the potential energy scan (PES) and the lowest energy conformer is selected for further investigation. Before going to the deep knowledge of bioactivities shown by the title compound, one must have in-depth knowledge about the molecular structure of the compound. The most robust computational tool, density functional theory (DFT) has been 42enhanced to a great extent, especially for the structural analysis of organic compounds, a computational exploration into the structural analysis of the title compound is particularly relevant. Detailed structural analysis has been done using H1 and C13 NMR as well as UV-visible spectroscopy. Moreover, the reports showing the detailed structural characterization of coumestrol is found to be rare and the reported papers are mostly focused on its bioactivities. In this scenario, the present work aims to explore a detailed computational approach towards the structural characterization of coumestrol. The work clearly explains the molecular structure, spectral characterizations, and frontier molecular orbital analysis. In addition, the global reactive and Fukui indices of the title compound have also been explained. The work can be extended to detailed bioactivity analysis, molecular docking analysis, QSAR/QSPR studies, etc.