Theoretical evaluation of antioxidant activity of tea catechins

Abstract

To quickly evaluate the antioxidant activity of tea catechins epicatechin (EC), epigallocatechin (EGC), epicatechingallate (ECG) and epigallocatechinsgallate (EGCG), a semi empiric quantum chemistry calculation methods were employed to calculate many parameters, such as molecular geometry, heat of formation (ΔfH), pKa, Mulliken charges, electrostatic potential, bond dissociation enthalpy (ΔdH), orbital's energy difference (Egap), Ovality, polarizability and polar surface area (PSA). Among calculated parameters only heat of formation (ΔfH), bond dissociation energy (ΔdH) and polar surface area (PSA) were correlated well with the antioxidant activity TEAC and DPPH values and give excellent correlation coefficients of 0.95, 0.98 and 0.94 successively. The results of such cheaper calculations can suitably scaled for predictive purpose.