Quantification of α-Thujone and Its Metabolites in Human Urine after Consumption of a Sage Infusion Using Stable Isotope Dilution Assays
1
Technical University of Munich, Chair of Analytical Food Chemistry, Maximus-von-Imhof-Forum 2, 85354 Freising, Germany
2
Department of Chemistry, University of Basel BPR 1096, Postfach 3350 Mattenstrasse 24a, CH-4002 Basel, Switzerland
3
Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, CH-4058 Basel, Switzerland
4
Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture and Food Innovation, the University of Queensland, Coopers Plains, QLD 4108, Australia
*
Author to whom correspondence should be addressed.
Toxins 2018, 10(12), 511; https://doi.org/10.3390/toxins10120511
Received: 21 October 2018 / Revised: 17 November 2018 / Accepted: 21 November 2018 / Published: 3 December 2018
(This article belongs to the Section Plant Toxins)
The metabolism of the monoterpene α-thujone was investigated in humans after consumption of sage tea, by analyses of its metabolites 2-hydroxythujone, 4-hydroxythujone, and 7-hydroxythujone in urine. For the quantitation of α-thujone and its metabolites, stable isotope dilution assays were developed. Using d6-α-thujone as internal standard, we quantified α-thujone by solid phase microextraction GC-MS and the hydroxythujones with d6-2-hydroxythujone, d6-4-hydroxythujone, and d6-7-hydroxythujone after glucuronide/sulfate deconjugation by LC-MS/MS in urine. After the consumption of 575.0 µg α-thujone, the 4-hydroxythujone and 7-hydroxythujone were detectable in the urine of the volunteers under study, after liberation from their glucuronides/sulfates. The 2-Hydroxythujone was not present in any of the volunteer samples above its detection limit. α-Thujone was detectable in a low amount, with a maximum concentration of 94 ng/L for the volunteer with the highest dose of 14.3 µg/kg bw.
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MDPI and ACS Style
Thamm, I.; Tiefenbacher, K.; Rychlik, M. Quantification of α-Thujone and Its Metabolites in Human Urine after Consumption of a Sage Infusion Using Stable Isotope Dilution Assays. Toxins 2018, 10, 511.
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