Lycopene in Humans

It is conceivable that the different carotenoids have specialized functions in different tissues as has been shown for the xanthophylls lutein and zeaxanthin, which are virtually the only carotenoids occurring in the macular area of the retina. The distribution of lycopene in human tissues is shown in Table 63.2 and Table 63.3. 

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Kucuk, O. et al.. Effects of lycopene supplementation in patients with localized prostate cancer, Exp. Biol. Med. (Maywood), 227, 881, 2002. van Breemen, R.B. et al.. Liquid chromatography-mass spectrometry of cis- and all-trans-lycopene in human serum and prostate tissue after dietary supplementation with tomato sauce, J. Agric. Food Chem., 50, 2214, 2002. 

Selective Resonance Raman Detection of Carotenes and Lycopene in Human Skin.104... 

SELECTIVE RESONANCE RAMAN DETECTION OF CAROTENES AND LYCOPENE IN HUMAN SKIN... 

Ermakov IV et al. (2005), Two-wavelength Raman detector for noninvasive measurements of carotenes and lycopene in human skin, SPIE Proc., 5686, 131-141. 

Liu, A, N Pajkovic, Y Pang, D Zhu, B Calamini, AL Mesecar, and RB van Breemen. 2006. Absorption and subcellular localization of lycopene in human prostate cancer cells. Mol Cancer Ther 5(11) 2879-2885. 

In systems where several carotenoids are involved, the absorption of each carotenoid is governed by interactions among them carotenoids compete for absorption (Furr and Clark 1997). For example, (3-carotene supplementation reduced absorption of dietary lutein and lycopene in humans (Micozzi and others 1992). Tyssandier and others (2002) found that the absorption of dietary lycopene was reduced when a portion of spinach or pills of lutein were additionally administered to the volunteers. Similarly, the absorption of dietary lutein was reduced by consumption of tomato puree or lycopene pills (Tyssandier and others 2002). Furusho and others (2000) demonstrated that liver retinol accumulation in Wistar rats was significantly reduced when a fixed amount of (3-carotene was replaced by a mixture of (3- and a-carotene, suggesting that each one of these carotenoids mutually inhibits the utilization of the other. The proportion of (3-and a-carotene in the mixture used in that study (Furusho and others 2000) simulated that of carrots. 

Concentration of Lycopene in Human Tissues (nmol/g Wet Tissue)... 

The biological activities of carotenoids, such as (3-carotene, are related to their provitamin A activity within the body (Clinton, 1998). Since lycopene lacks the (3-ionic ring structure, it does not have any provitamin A activity (Stahl and Sies, 1996). The biological effects of lycopene in humans have therefore been attributed to mechanisms other than vitamin A. Two major hypotheses have been proposed to explain the anticarcinogenic and antiatherogenic activities of lycopene oxidative and nonoxidative mechanisms. The proposed mechanisms for the role of lycopene in the prevention of chronic diseases are summarized in Figure 6. 

Khachik, R, Steck, A., and Pfander, H., Bioavailability, metabolism, and possible mechanism of chemoprevention by lutein and lycopene in humans, in Food Factors for Cancer Prevention, Ohigashi, H., Osawa, T., Terao, J., Watanabe, S., Yoshikawa, T., Eds., Springer-Verlag, Tokyo, 1997, p. 542. 

Lycopene is the major carotenoid pigment found in tomatoes, along with lesser amounts of a-, P-, y-, and -carotene, phytoene, phytofluene, neurosporene, and lutein (Trombly and Porter, 1953 Kargl et al., 1960). The basic physicochemical information on lycopene is fairly well established and is outlined in Table 4.1. Lycopene is dispersible in edible oils and soluble in apolar organic solvents. In aqueous systems, lycopene tends to aggregate and to precipitate as crystals this behavior is suspected to inhibit the bioavailability of lycopene in humans (Zumbrunn et al., 1985). In fresh tomatoes, the crystalline form of lycopene is responsible for the typical bright red of the ripe fruits. 

The potential beneficial effects of lycopene in human health have been reviewed extensively in recent years [39-45] numerous observational studies have consistently shown an inverse relationship between the consumption of lycopene-rich diets (tomato or tomato-based foods) or plasma lycopene levels with the risk of cancers at various sites [46, 47]. The strongest inverse relationship was that for prostate cancer [2, 46-49], one of the most prevalent male cancers in the western populations and common across the world other significant inverse relationships were found with lung and stomach cancers. 

Reifen, R., Haftel, L., Faulks, R. et al (2003) Plasma and buccal mucosal cell response to short-term supplementation with all- frflns-carotene and lycopene in human volunteers. Int. J. Mol Med., 12, 989-993. 

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