Abstract
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 (14)C-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 approximately 6 mug [6,6',7,7'-(14)C]lycopene ( approximately 30,000 Bq; 92% trans lycopene). The appearance of (14)C in plasma, plasma triacylglycerol-rich lipoprotein (TRL) fraction, urine, expired breath carbon dioxide, and skin biopsies was measured over 42 d. The (14)C in lycopene-isomer fractions from plasma and TRL fraction was measured to assess the isomerization of lycopene in vivo.
RESULTS: We quantified (14)C from (14)C-lycopene in plasma, the plasma TRL fraction, expired carbon dioxide, urine, and skin. The time to maximum concentration (t(max)) of total (14)C-lycopene in plasma was 6 h, and the elimination half-life (t(1/2)) was 5 d, which were different from the t(max) and t(1/2) of unlabeled lycopene (0.5 and 48 d, respectively). (14)C-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 (14)CO(2) after dosing, which implies that beta-oxidation was involved in the lycopene metabolism. Lycopene or its metabolites were detected in skin for up to 42 d.
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 (14)C-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 approximately 6 mug [6,6',7,7'-(14)C]lycopene ( approximately 30,000 Bq; 92% trans lycopene). The appearance of (14)C in plasma, plasma triacylglycerol-rich lipoprotein (TRL) fraction, urine, expired breath carbon dioxide, and skin biopsies was measured over 42 d. The (14)C in lycopene-isomer fractions from plasma and TRL fraction was measured to assess the isomerization of lycopene in vivo.
RESULTS: We quantified (14)C from (14)C-lycopene in plasma, the plasma TRL fraction, expired carbon dioxide, urine, and skin. The time to maximum concentration (t(max)) of total (14)C-lycopene in plasma was 6 h, and the elimination half-life (t(1/2)) was 5 d, which were different from the t(max) and t(1/2) of unlabeled lycopene (0.5 and 48 d, respectively). (14)C-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 (14)CO(2) after dosing, which implies that beta-oxidation was involved in the lycopene metabolism. Lycopene or its metabolites were detected in skin for up to 42 d.
| Original language | English |
|---|---|
| Pages (from-to) | 1263-1273 |
| Number of pages | 11 |
| Journal | American Journal of Clinical Nutrition |
| Volume | 93 |
| Issue number | 6 |
| Early online date | 04 May 2011 |
| DOIs | |
| Publication status | Published - Jun 2011 |
| Externally published | Yes |