Insights into the HO· and HOO· radical scavenging activity of aryl carbamate derivative: a computational mechanistic and kinetic investigation

Aryl carbamates exhibit significant utility due to their diverse range of biological activities, including anticancer, antituberculosis, and antioxidant properties. This study will focus on a comparative evaluation of the antioxidant capabilities of two aryl carbamate derivatives, namely Methyl(Z)-(1-(hydroxyamino) ethyl)-5-(methoxycarbonyl) amino)-2-methyl-1H-indole 1 carboxylate (Compound 1) and Dimethyl (1,3-dioxo-2,3-dihydro-1H-indene-2,2-diyl) bis (4,1 phenylene) dicarbamate (Compound 2). To assess the anti-oxidant capacity, two distinct reactive oxygen species, such as highly reactive hydroxyl (HO^·) and moderately reactive hydroperoxyl (HOO^·), have been taken into consideration. Four distinct scavenging processes, including RAF, HAT, SETPT, and SPLET, have been investigated here. The RAF mechanism was determined to be the most effective anti-oxidant pathway, regardless of the compounds or free radicals investigated here. For both HO^· and HOO^·, compound 1 demonstrated more potent scavenging capabilities than compound 2. Compounds 1 and 2 react with the HO^· radical very quickly due to its extraordinarily high reactivity; in contrast, the less reactive HOO^· provides a rather moderate rate. The calculated values of overall rate constant of Comp. 1 reaction with HOO^· are 3.7 × 10³ M⁻¹ s⁻¹ (gas phase), 5.3 × 10¹ M⁻¹ s⁻¹ (water), and 3.6 × 10⁰ M⁻¹ s⁻¹ (pentyl ethanoate). With this context it is clear both of the compounds can work as strong and mild antioxidant against HO^· and HOO^· radical, respectively.