Bioavailability, Absorption and Subcellular Localization of Lycopene in Human Body2010-02-12
Lycopene is a pigment, unsolvable in water. After ingestion, lycopene is soluble by bile, absorbed and incorporated into lipid micelles in the small intestine. In its natural, lycopene molecule is all-trans form, while it is isomerized in the stomach as a result of low pH. Most researchers suggested that formation of cis-isomers also increases bioavailability of lycopene. All detectable cis-lycopene forms in human tissues are more than 15 isomers. So the potential role for specific lycopene cis-isomers in biological functions has stimulated interest by researchers.
The absorbed lycopene will be transferred to the tissues via blood, and accumulated in blood, liver, intestine, brain and other organs. These are all important organs of human; hence lycopene is prominent in protecting various human organs.
★ Clinton SK, et al. Cis-trans lycopene isomers, carotenoids, and retinol in the human prostate. Cancer Epidemiol Biomarkers & Prev 1996; 5:823–833. (http://cebp.aacrjournals.org/cgi/reprint/5/10/823)
★ Boileaul TW, et al. Bioavailability of all-trans and cis-isomers of lycopene. Exp Biol Med 2002; 227:914–919. (http://www.ebmonline.org/cgi/reprint/227/10/914)
★ Liu A, et al. Absorption and subcellular localization of lycopene in human prostate cancer cells. Mol Cancer Ther 2006; 5: 2879-85. (http://mct.aacrjournals.org/content/5/11/2879.full.pdf)
Lycopene uptake varied with individuals, but peak serum concentrations were always reached between 24 and 48 hours. The carotenoid was eliminated from serum with a half-life of 2 to 3 days. So the retention period of lycopene in human body is about 1 week.
★ Stahl W & Sies H. Uptake of lycopene and its geometrical isomers is greater from heat-processed than from unprocessed tomato juice in humans. J. Nutr. 1992; 122: 2161-2166. (http://jn.nutrition.org/cgi/reprint/122/11/2161.pdf)
There are several other reports stating that the metabolites of lycopene may also play an important role. And the related researches are in the ascendant to find out more details.
★ Ruhl R, et al. Carotenoids and their metabolites are naturally occurring activators of gene expression via the pregnane X receptor. Eur J Nutr 2004; 43: 336–343. (http://www.springerlink.com/content/uudqbwlb7h0tu80e/)