In Silico Study of the Radical Scavenging Activities of Natural Indole-3-Carbinols.

Enzymatic hydrolysis of indole glucosinolates in the human body yields the Indole-3-carbinol family of compounds (I3Cs). I3Cs are implicated in the self-healing processes of the human body and thus used as over the counter dietary supplements characterized as potential antioxidants. In this study, the antioxidant activity of natural indole-3-carbinol derivatives were investigated against the HOO• radical by using thermodynamic and kinetic calculations. It was found that natural I3Cs containing only C8-H and/or N1-H bonds such as indole-3-carbinol, 4-methoxy-indole-3-carbinol, and 1-methoxy-indole-3-carbinol exhibit weak antioxidant properties. However, the presence of OH groups in the indole ring significantly increases the radical scavenging in aqueous as well as lipid media. In particular the HOO• scavenging activity of 1-hydroxyl-indole-3-carbinol far exceeds that of Trolox, 2.0 times in aqueous medium and 352.9 times in lipid (pentyl ethanoate) medium. This suggests that 1-hydroxyl-indole-3-carbinol is one of the most powerful known antioxidants in lipid environments, pointing at potential dietary application in preventive and regenerative medicine.