2. Academic Validation
  3. UPLC-ESI-Q-TOF-MS(E) identification of urinary metabolites of the emerging sport nutrition supplement methoxyisoflavone in human subjects

UPLC-ESI-Q-TOF-MS(E) identification of urinary metabolites of the emerging sport nutrition supplement methoxyisoflavone in human subjects

  • J Pharm Biomed Anal. 2014 Aug 5:96:127-34. doi: 10.1016/j.jpba.2014.03.031.
Yannick Lecompte 1,  Martine Rosset 2,  Camille Richeval 3,  Luc Humbert 3,  Patrick Arpino 4
Affiliations

Affiliations

  • 1 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.
  • 2 Service de Santé des Armées, État-Major de la Marine, 2 rue Royale, 75008 Paris, France.
  • 3 Laboratoire de Toxicologie et de Génopathies, Centre de Biologie Pathologie, Centre Hospitalier Régional Universitaire, boulevard du professeur Jules Leclercq, 59037 Lille, France.
  • 4 Laboratoire d'Electrochimie, Chimie des Interfaces et Modélisation pour l'Energie (LECIME, UMR7575) - Chimie-Paristech, 11 rue Pierre et Marie Curie, 75231 Paris, France.
PMID: 24742771 DOI: 10.1016/j.jpba.2014.03.031
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.

Keywords

5-Methyl-7-methoxyisoflavone; Isoflavones; Mass spectrometry; Metabolism; Urine.

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