Conformational study of naringenin in the isolated and solvated states by semiempirical and AB Initio methods.

Abstract

Naringenin is a natural widespread flavanone occurring in different foodstuffs that presents several important biological activities. Although its properties are well documented, its mechanisms of action are still controversial. The present article reports a conformational analysis of naringenin, using the semiempirical AM1 and ab initio methods, at the Hartree-Fock level of theory. The 3-21G, 3-21G*, 6-31G, and 6-31G** basis sets were used. The electron correlation effects were included through the M011er-Plesset second-order perturbation theory. The solvation of naringenin has been investigated through the standard SCRF, the supermolecule (SM), and the combined SM/SCRF models. The results have shown that there are two degenerate forms of naringenin, differing mainly by the orientation of a hydroxyl group (C4'—OH). The energy barrier for the interconversion between them is ca. 6 kcal.mol-1, suggesting some conjugation between the p-system of the aromatic B ring and the hydroxyl group (C4'—OH).