title: Formation of tetrahydro-beta-carbolines and beta-carbolines during the reaction of L-tryptophan with D-glucose.
abstract: The reaction of L-tryptophan (Trp) with D-glucose under conditions that can occur during food processing and preparation was studied by high-performance liquid chromatography with diode array detection (HPLC/DAD). Besides the well-established glucose-tryptophan Amadori product (AP), (1R,3S)-1-(D-gluco-1,2,3,4,5-pentahydroxypentyl)-1,2,3, 4-tetrahydro-beta-carboline-3-carboxylic acid (PHP-THbetaC) was identified as an important product of this reaction. For preparation, PHP-THbetaC was obtained in high yields when Trp and D-glucose were reacted under strongly acidic conditions after heating in methanol. At elevated reaction temperatures (150 degrees C) 1-acetyl-beta-carboline (acetyl-betaC), was detected in significant concentrations. The mixtures were heated under variations of reaction time and temperature, and AP, PHP-THbetaC, and acetyl-betaC were quantified. In the presence of air oxygen or mild, food relevant oxidants, such as L-dehydroascorbic acid, PHP-THbetaC was readily oxidized to a product that was identified as the previously unknown 1-(D-gluco-1,2,3,4,5-pentahydroxypentyl)-beta-carboline (PHP-betaC). Formation of PHP-THbetaC and PHP-betaC in foodstuffs would deserve particular interest because multiple physiological activity of THbetaC and betaC derivatives has been shown previously.
authors.affiliation: Institut für Pharmazie und Lebensmittelchemie der Universität München, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Rönner
authors.forename: H
authors.initials: H
authors.lastname: Lerche
authors.forename: W
authors.initials: W
authors.lastname: Bergmüller
authors.forename: C
authors.initials: C
authors.lastname: Freilinger
authors.forename: T
authors.initials: T
authors.lastname: Severin
authors.forename: M
authors.initials: M
authors.lastname: Pischetsrieder
mesh_terms: D002243:Carbolines / Q000737:chemistry*; D002622:Chemistry, Agricultural; D005947:Glucose / Q000737:chemistry*; D014364:Tryptophan / Q000737:chemistry*
chemical_list: C583241:1-acetyl-beta-carboline; D002243:Carbolines; D014364:Tryptophan; D005947:Glucose