Bisphenols analogues derived from natural phenols: synthesis and evaluation of antioxidant capacity

Abstract

A series of symmetric methylenebisphenols based on sesamol (1), 2-methoxybenzene-1,4-diol (2), eugenol (3), carvacrol (4), and thymol (5) was synthesized using the condensation reaction between these phenols and paraformaldehyde. We carried out a comparative evaluation of the antioxidant properties of both parent compounds 1–5 and the products derived from them. The conversion of sesamol (1), eugenol (3), and thymol (5) to the corresponding methylenebisphenols is associated with a significant increase in the antioxidant activity (AOA) of the synthesized compounds, measured by the degree of inhibition of Fe²⁺/ascorbate-induced fatty acid oxidation of mouse brain lipids. The derivatives are superior to the original natural phenols in terms of their ability to improve the survival of red blood cells (RBCs) of lab mice and protect their hemoglobin from oxidation under the conditions of hemolysis induced by 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) or hydrogen peroxide. In terms of several parameters, the activity of the synthesized products exceeded that of the synthetic antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT).

Graphical abstract