Carboxymethylnaringenin: a promising antioxidant in the aqueous physiological environment.

The synthetic naringenin derivative (2S)-8-carboxymethylnaringenin (CMN) was developed for the treatment of bacterial and viral respiratory infections. There are indications that CMN may act as an antioxidant, however, no studies have been conducted in this regard. This work is aimed at assessing the antiradical capacity of CMN against various physiologically relevant species in physiological environments by using thermodynamic and kinetic calculations. According to the results, CMN only exhibits modest HOO^• antiradical activity in lipid medium, modeled here as pentyl ethanoate solvent, with an overall rate constant (k_overall) of 2.01 × 10² M^-1 s^-1. However, significant antiradical activity is predicted for the aqueous medium (k_overall = 2.60 × 10⁵ M^-1s^-1) that is equivalent to the activity of the reference antioxidant Trolox. In a screen performed on a range of radicals, HO^•, NO₂, SO₄^•-, N₃^•, CH₃O^•, CCl₃O^•, CH₃OO^•, and CCl₃OO^• were also successfully scavenged by CMN in water at physiological pH. Therefore, other than a potent drug, CMN is also a good antioxidant in polar environments.