title: Hydroxyl radical reactions and the radical scavenging activity of β-carboline alkaloids.
abstract: β-Carbolines are bioactive pyridoindole alkaloids occurring in foods, plants and the human body. Their activity as hydroxyl radical (OH) scavengers is reported here by using three different methods: deoxyribose degradation, hydroxylation of benzoate and hydroxylation of 2'-deoxyguanosine to give 8-hydroxy-2'-deoxyguanosine (8-OHdG) as assessed by RP-HPLC (MS). Fenton reactions (Fe(2+)/Fe(3+) plus H2O2) were used for OH generation, and the radical increased in the presence of ascorbic acid or 6-hydroxydopamine as pro-oxidants. β-Carbolines were scavengers of OH in the three assays and in the presence of pro-oxidants. Tetrahydro-β-carboline-3-carboxylic acids were active against the hydroxylation of 2'-deoxyguanosine. β-Carbolines reacted with hydroxyl radicals (OH) affording hydroxy-β-carbolines, whereas tetrahydro-β-carbolines gave oxidative and degradation products. On the basis of IC50 and reaction rates (k), β-carbolines (norharman and harman), and tetrahydro-β-carbolines (tetrahydro-β-carboline, 1-methyltetrahydro-β-carboline and pinoline) were good OH radical scavengers and their activity was comparable to that of the indole, melatonin, which is an effective hydroxyl radical scavenger and antioxidant.
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN), Spanish National Research Council (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain. Electronic address: therraiz@ictan.csic.es.
authors.forename: Tomás
authors.initials: T
authors.lastname: Herraiz
authors.affiliation: Instituto de Ciencia y Tecnología de Alimentos y Nutrición (ICTAN), Spanish National Research Council (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Galisteo
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000470:Alkaloids / Q000737:chemistry / Q000494:pharmacology*; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology; D001205:Ascorbic Acid / Q000737:chemistry; D002243:Carbolines / Q000737:chemistry / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry / Q000494:pharmacology*; D008550:Melatonin / Q000737:chemistry / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D016627:Oxidopamine / Q000737:chemistry
chemical_list: D000470:Alkaloids; D000975:Antioxidants; D002243:Carbolines; D017665:Hydroxyl Radical; D000080242:8-Hydroxy-2'-Deoxyguanosine; D016627:Oxidopamine; D006861:Hydrogen Peroxide; D003849:Deoxyguanosine; D008550:Melatonin; D001205:Ascorbic Acid
keywords: 1,2,3,4-Tetrahydro-beta-carboline (PubChem CID: 107838); 1,2,3,4-Tetrahydro-beta-carboline-3-carboxylic acid (PubChem CID: 98285); 1-Methyl-1,2,3,4-tetrahydro-beta-carboline (PubChem CID: 91522); 1-Methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (PubChem CID: 73530); 6-Hydroxydopamine (PubChem CID: 4624); 8-Hydroxy-2′-deoxyguanosine; Antioxidants; Ascorbic acid (PubChem CID: 54678501); Benzoate; Deoxyribose; Harman (PubChem CID: 5281404); Hydroxyl radical scavengers; Indoles; Melatonin; Melatonin (PubChem CID: 896); Norharman (PubChem CID: 64961); Pinoline (PubChem CID: 1868); Pyridoindoles; Tetrahydro-β-carbolines; β-Carboline alkaloids