Antiradical Activity of Polycyclic Compounds with Indole and Isoindole Moieties

Abstract

The antiradical activity of polycyclic compounds with indole and isoindole moieties was evaluated in vitro using a number of assays. All tested compounds, except for 3,5-di(tert-butyl)-4-hydroxybenzenecarbaldehyde N-(2-oxo-1,2-dihydro-3H-indole-3-ylidene)hydrazone, demonstrated much lower activity towards DPPH, ABTS^•+, and NO^• radicals than the well-known antioxidant ionol. All compounds showed a high radical-scavenging capacity relative to the superoxide radical anion generated in the enzymatic (NBT assay) and non-enzymatic (epinephrine autoxidation) systems. The high antiradical activity of 3,5-di(tert-butyl)-4-hydroxybenzenecarbaldehyde N-(2-oxo-1,2-dihydro-3H-indol-3-ylidene) hydrazone is attributable to the presence of 2,6-di-tert-butylphenol, indoline, and azine moieties, which promote the formation of a stable intermediate.