title: N-methylated derivatives of tyramine in citrus genus plants: identification of N,N,N-trimethyltyramine (candicine).
abstract: The distribution of tyramine and its methylated derivatives, N-methyltyramine and N,N-dimethyltyramine, was investigated in tissue parts (leaves and fruits) of several plants of Citrus genus by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). In the course of our study we discovered the occurrence of N,N,N-trimethyltyramine in all citrus plants examined. This quaternary ammonium compound, known to act in animals as a neurotoxin, was recognized and characterized by mass spectrometric analysis. The substance, never described before in the Citrus genus, is also known as candicine or maltoxin. Results indicate that N,N,N-trimethyltyramine is consistently expressed in leaves of clementine, bitter orange, and lemon. Conversely, low levels were found in the leaves of orange, mandarin, chinotto (Citrus myrtifolia), bergamot, citron, and pomelo. In the edible part of the fruits, N,N,N-trimethyltyramine was found at trace levels.
authors.affiliation: Dipartimento di Biochimica, Biofisica e Patologia Generale, Seconda Università degli Studi di Napoli , Via L. De Crecchio 7, 80138 Napoli, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Servillo
authors.forename: Alfonso
authors.initials: A
authors.lastname: Giovane
authors.forename: Nunzia
authors.initials: N
authors.lastname: D'Onofrio
authors.forename: Rosario
authors.initials: R
authors.lastname: Casale
authors.forename: Domenico
authors.initials: D
authors.lastname: Cautela
authors.forename: Giovanna
authors.initials: G
authors.lastname: Ferrari
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Balestrieri
authors.forename: Domenico
authors.initials: D
authors.lastname: Castaldo
mesh_terms: D002957:Citrus / Q000737:chemistry* / Q000145:classification; D005638:Fruit / Q000737:chemistry; D008745:Methylation; D015394:Molecular Structure; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D053719:Tandem Mass Spectrometry; D014439:Tyramine / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D014439:Tyramine