title: Indole-3-carbinol inhibits lipid peroxidation in cell-free systems.
abstract: Free radicals mediate toxicological and carcinogenic responses of tissues to many chemicals. Cellular defenses against radical mediated damage utilize endogenous substances such as tocopherol, ascorbate and GSH. Here we report a new antioxidant, indole-3-carbinol (I-3-C), a natural constituent of human diet. In chlorobenzene containing soy phospholipids, lipid oxidation was initiated with azobisisobutyronitrile; I-3-C inhibited formation of thiobarbituric acid-reactive material in a dose-dependent manner. Similar results were obtained in an aqueous system containing phospholipid vesicles initiated by Fe/ascorbate. For both systems I-3-C was less effective than tocopherol or BHT as antioxidant. To assess these antioxidant effects in vivo, mice were treated with I-3-C by gavage. A hepatic post-mitochondrial supernatant fraction isolated 2 hours after treatment showed dose-dependent decreases in NADPH-mediated lipid oxidation which correlated with decreases in 14C-nitrosodimethylamine covalent binding to protein. Although hepatotoxicity may not involve lipid oxidation per se, it does indicate that free radical damage had occurred. Inhibition of damage by I-3-C suggests that this dietary component has the potential to ameliorate radical mediated chemical toxicity.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D005609:Free Radicals; D006801:Humans; D007211:Indoles / Q000494:pharmacology*; D007700:Kinetics; D008054:Lipid Peroxides / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology*; D010743:Phospholipids / Q000378:metabolism
chemical_list: D005609:Free Radicals; D007211:Indoles; D008054:Lipid Peroxides; D009570:Nitriles; D010743:Phospholipids; C016517:indole-3-carbinol; C004526:azobis(isobutyronitrile)