Among the 600 known carotenoids in nature, only about 20 are found in the human plasma and tissues. Lycopene is the most predominant carotenoid in the human plasma. Lycopene, is named after "Lycopersicon lycopersicum" - a species of tomato.
Physical Characteristics:
Like all carotenoids, it is:
- lipophilic (has an affinity to fat or lipids) and is thus fat-soluble. It is also soluble in solvents like alcohol. It is not water-soluble. It is present in the low-density lipoprotein -cholesterol (LDL) and very low-density lipoprotein cholesterol (VLDL) fractions of the serum. http://Institut de L'Information Scientifique et Technologie (CAT. INIST)
- an acyclic isomer of beta-carotene. Acyclic means the molecule does not contain "rings." Beta-carotene, contains 2 Benzene rings; one on each end of the molecule. An isomer is any one of 2 or more substances composed of the same elements in the same proportions but exhibit different properties. The molecular formula for lycopene and beta-carotene is: C40H56.
- not converted to vitamin A in the human body. This is due to the absence of the Benzene rings.
- present in the all-trans configuration in fresh tomato and other fruits. It is transformed into the cis-configuration during processing as cellular walls are broken down and lycopene is released from the food matrix. The bioavailability of lycopene is enhanced with processing. Cis -isomers are more readily absorbed by the body than trans-molecules.
- photo-sensitive to all colors of the visible light spectrum except "red" light meaning; it absorbs all light except red light.
- the red pigment found in tomatoes and other lycopene-rich fruits.
Physiologic Properties
- As an antioxidant, lycopene can inhibit cancer growth by interfering with cell growth factor receptor signalling and cell cycle progression particularly in prostate cancer cells.Pharmainfo.net
- It prevents the oxidation of LDL cholesterol and platelet aggregation (clumping), thereby inhibiting the development of atherosclerosis- the deposition of fat and plaque along arterial walls or wall. It also prevents venous thrombosis - blood clotting in the veins.
- Lycopene synergistically interacts with other antioxidants to inhibit carcinogenesis or tumorigenesis. For example, lycopene acts with vitamin D3 to reduce cell proliferation and differentiation in HL-60 promyelocytic leukemia cell line, indicating interaction at the nuclear and sub-nuclear levels.
- It protects DNA from damage thereby preventing cellular mutagenesis or the transformation of normal cells into malignant entities.
- It can "dissolve" the outer membranes of bacteria such as P. gingivalis (causes gum inlammation) and fungus such as Candida albicans - an opportunistic fungus that can trigger mouth and genital infections in humans.
- It is anti-toxic against Aflatoxin, Cyclosporin and Cadmium - a heavy metal element. Aflatoxin is a naturally occuring mycotoxin produced by Aspergillus niger. Cyclosporin is an immunosuppressant drug.
Significant Food Sources
Lycopene is abundant in tomatoes and tomato products such as tomato paste, juice, and sauce. It is also found in watermelon, guavas, papaya, and grapefruit in varying amounts.
References
Tapiero H, Townsend D & Tew KD. "The role of carotenoids in the prevention of human pathologies"J Biomedicine and Pharmacotherapy March 2004; 58(2):100.110
David Heber "Phytochemicals beyond Antioxidation" J Nutrition November 2004;134:3175-3176
Chandra RV et al. "Efficacy of lycopene in the treatment of gingivitis: a randomized, placebo controlled clnical trial." J Nutrition January 2008;138(1):149-153
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