Quantum Mechanical Studies on Free Energy of Solution of some Vitamins and their Correlation with Bioavailability

Polarizable Continuum Model (PCM) analysis has been carried out using B3LYP method with 6-311++G(d,p) basis set for three water soluble vitamins (biotin, L-ascorbic acid and pyridoxine) and one fat soluble vitamin (phylloquinone) in ten solvents with wide range of dielectric constants. In this paper, we report electrostatic, dispersion and repulsive interaction components of Gibb's free energy of solvation along with cavitation energies for these systems. The induced dipole moments of these four vitamins in ten solvents are calculated and correlated with the dielectric constant of solvent. The interaction energies of the systems are discussed in terms of dielectric constant, index of refraction and surface tension of the solvents. Solvation energies of the four vitamins in aqueous medium are correlated with their bioavailability.