title: Tetrahydro-beta-carboline alkaloids that occur in foods and biological systems act as radical scavengers and antioxidants in the ABTS assay.
abstract: Tetrahydro-beta-carboline alkaloids that occur in foods such as wine, seasonings, vinegar and fruit products juices, jams) acted as good radical scavengers (hydrogen- or electron donating) in the ABTS (2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) assay, and therefore, they could contribute to the beneficial antioxidant capacity attributed to foods. In contrast, the fully aromatic beta-carbolines norharman and harman did not show any radical scavenger activity in the same assay. During the reaction with ABTS.+ radical cation, tetrahydro-beta-carboline-3-carboxylic acid such as 1-methyl-1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (MTCA) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline-1,3-dicarboxylic acid (MTCA-COOH) were converted to harman, whereas 1,2,3,4-tetrahydro-beta-carboline-3-carboxylic acid (THCA) and 1,2,3,4-tetrahydro-beta-carboline-1,3-dicarboxylic acid (THCA-COOH) afforded norharman. These results suggest that food and naturally-occurring tetrahydro-beta-carboline alkaloids if accumulated in tissues, as reported elsewhere, might exhibit antioxidant activity.
authors.affiliation: therraiz@ifi.csic.es
authors.forename: Tomas
authors.initials: T
authors.lastname: Herraiz
authors.forename: Juan
authors.initials: J
authors.lastname: Galisteo
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D052160:Benzothiazoles; D002243:Carbolines / Q000378:metabolism / Q000494:pharmacology*; D002412:Cations; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D005504:Food Analysis; D005609:Free Radicals / Q000494:pharmacology; D008401:Gas Chromatography-Mass Spectrometry; D006247:Harmine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007202:Indicators and Reagents / Q000494:pharmacology; D008956:Models, Chemical; D013451:Sulfonic Acids / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D002243:Carbolines; D002412:Cations; D005609:Free Radicals; D007202:Indicators and Reagents; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D006247:Harmine; C009804:tryptoline; C005010:harman; C010262:norharman