DFT/B3LYP study of the substituent effects on the reaction enthalpies of the antioxidant mechanisms of Indole-3-Carbinol derivatives in the gas-phase and water

► Electron-donating substituents induce a rise in PDE and PA values in comparison to the basic structure. ► Electron-withdrawing groups cause increase in the IP, ETE and BDE values in comparison to the basic structure. ► The SPLET and HAT mechanism represents the thermodynamically favored process in water and gas phase, respectively.