title: UPLC-ESI-Q-TOF-MS(E) identification of urinary metabolites of the emerging sport nutrition supplement methoxyisoflavone in human subjects.
abstract: Methoxyisoflavone (5-methyl-7-methoxyisoflavone) is a synthetic isoflavone used by bodybuilders for its ergogenic properties. A recent study demonstrated that methoxyisoflavone metabolites can induce false-positive results in urinary immunoassay screening tests for cannabinoids, and only one metabolite has been identified. To improve the knowledge on the metabolic pathways of methoxyisoflavone, ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF) was applied. Urine samples were obtained from methoxyisoflavone regular users. After enzymatic hydrolysis and liquid-liquid extraction, the samples were analyzed by UPLC-Q-TOF fitted with an electrospray ionization source (ESI) operating under positive ion mode. Mass data were acquired with the MS(E) method. Five metabolites were identified. Those were divided into two metabolic pathways, depending on whether the B ring hydroxylation was preceded or not by the O-demethylation of the methoxy group. The MS(E) mass spectra of methoxyisoflavone and its metabolites are specific of isoflavones structures and revealed 1,3 retro Diels-Alder fragmentation and double CO loss. Losses of small neutral molecules CO and H2O, and radical CH3, typical of flavonoids, were also observed. This study illustrates the capacity of the sensitive UPLC-Q-TOF analytical system, combined with the MS(E) method of collection of fragmentation data, to rapidly elucidate the unknown xenobiotics metabolism.
authors.affiliation: Service de Santé des Armées, Service de Protection Radiologique des Armées, 1 bis rue du lieutenant Raoul Batany, 92141 Clamart, France. Electronic address: lecompte.yann@free.fr.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Lecompte
authors.affiliation: Service de Santé des Armées, État-Major de la Marine, 2 rue Royale, 75008 Paris, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Rosset
authors.affiliation: Laboratoire de Toxicologie et de Génopathies, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, boulevard du professeur Jules Leclercq, 59037 Lille, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Richeval
authors.affiliation: Laboratoire de Toxicologie et de Génopathies, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, boulevard du professeur Jules Leclercq, 59037 Lille, France.
authors.forename: Luc
authors.initials: L
authors.lastname: Humbert
authors.affiliation: Laboratoire d'Electrochimie, Chimie des Interfaces et Modélisation pour l'Energie (LECIME, UMR7575) - Chimie-Paristech, 11 rue Pierre et Marie Curie, 75231 Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Arpino
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019587:Dietary Supplements / Q000032:analysis*; D005260:Female; D005419:Flavonoids / Q000032:analysis / Q000652:urine; D006801:Humans; D007529:Isoflavones / Q000032:analysis / Q000378:metabolism* / Q000652:urine; D059625:Liquid-Liquid Extraction; D008297:Male; D008875:Middle Aged; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013177:Sports
chemical_list: C000594263:5-methyl-7-methoxyisoflavone; D005419:Flavonoids; D007529:Isoflavones
keywords: 5-Methyl-7-methoxyisoflavone; Isoflavones; Mass spectrometry; Metabolism; Urine