QSPR Correlation of Physico-chemical Descriptors with the Molecular Surface Area and Rf of Ten Polyphenolic Compounds, Separated from Vegetal Extracts by TLC

Polyphenols are important constituents of plants, being demonstrated that long term consumption of them have potential health benefits as antioxidant. In the experimental part of the study we separated ten polyphenolic compounds by thin layer chromatography (TLC) from hydroalcoholic hypoglycemic plant extracts (Ericaceae family). In the theoretical study part we consider important to characterize the structural properties of the substances using molecular mechanics studies. The selected physico-chemical descriptors were: HOMO and LUMO orbitals frontier, water solubility, partition coefficient, dipole moment, heat of formation, stabilization energy of the molecule and number of proton donor groups. We realized a comparative QSPR regression correlation study of molecular surface area and Rf with the selected desriptors. From studies we observed the relationship between the two parameters Rf and MSA, which correlates very well with common descriptors.

On the relation between Zenkevich and Wiener indices of alkanes

A relatively complicated relation was found to exist between the quantity U recently introduced by Zenkevich (providing a measure of internal molecular energy), and the Wiener index W (measuring molecular surface area and intermolecular forces). We now report a detailed analysis of this relation and show that, in the case of alkanes, its main features are reproduced by the formula U = ??W + ? + ??1; where ?1 is the number of methyl groups, and ?, ? and ? are constants, depending only on the number of carbon atoms. Thus for isomeric alkanes with the same number of methyl groups, U and W are linearly correlated.