Lycopene bioavailability and metabolism in humans: an accelerator mass spectrometry study

• Published in: The American journal of clinical nutrition Vol. 93; no. 6; pp. 1263 - 1273
• Main Authors: Ross, Alastair B, Vuong, Le Thuy, Ruckle, Jon, Synal, Hans Arno, Schulze-König, Tim, Wertz, Karin, Rümbeli, Robert, Liberman, Rosa G, Skipper, Paul L, Tannenbaum, Steven R, Bourgeois, Alexandre, Guy, Philippe A, Enslen, Marc, Nielsen, Inge Lise F, Kochhar, Sunil, Richelle, Myriam, Fay, Laurent B, Williamson, Gary
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01-06-2011; American Society for Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: Adult; Biological and medical sciences; Biological Availability; Biopsy; Breath Tests; Carbon Dioxide - metabolism; Carbon Isotopes - metabolism; Carotenoids - blood; Carotenoids - metabolism; Carotenoids - pharmacokinetics; Feeding. Feeding behavior; Functional foods & nutraceuticals; Fundamental and applied biological sciences. Psychology; Humans; Isomerism; Lipoproteins - blood; Lycopene; Male; Mass spectrometry; Mass Spectrometry - methods; Metabolism; Middle Aged; Phytochemicals; Skin - metabolism; Studies; Triglycerides - blood; Urinalysis; Urine; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Human; Bioavailability; Metabolism; Mass spectrometry; Lycopene
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.110.008375

Background: To our knowledge, there is no direct information on lycopene metabolism in humans.Objective: The objective of this study was to quantify the long-term human bioavailability of lycopene in plasma and skin after a single dose of 14C-lycopene and to profile the metabolites formed.Design: We preselected 2 male subjects as lycopene absorbers and gave them an oral dose of 10 mg synthetic lycopene combined with ≈6 μg [6,6′,7,7′-14C]lycopene (≈30,000 Bq; 92% trans lycopene). The appearance of 14C in plasma, plasma triacylglycerol–rich lipoprotein (TRL) fraction, urine, expired breath carbon dioxide, and skin biopsies was measured over 42 d. The 14C in lycopene-isomer fractions from plasma and TRL fraction was measured to assess the isomerization of lycopene in vivo.Results: We quantified 14C from 14C-lycopene in plasma, the plasma TRL fraction, expired carbon dioxide, urine, and skin. The time to maximum concentration (tmax) of total 14C-lycopene in plasma was 6 h, and the elimination half-life (t1/2) was 5 d, which were different from the tmax and t1/2 of unlabeled lycopene (0.5 and 48 d, respectively). 14C-Lycopene was extensively isomerized after dosing as a 92% all-trans isomer at dosing but changed to 50% trans, 38% 5 cis, 1% 9 cis, and 11% other cis isomers after 24 h. A similar pattern of isomerization was seen in plasma TRL fractions.Conclusions: Lycopene was extensively isomerized after dosing and rapidly metabolized into polar metabolites excreted into urine with the rapid peak of 14CO2 after dosing, which implies that β-oxidation was involved in the lycopene metabolism. Lycopene or its metabolites were detected in skin for up to 42 d.