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Abstracts

Life Extension Magazine September 2012
Abstracts

Lycopene

Lycopene inhibits matrix metalloproteinase-9 expression and down-regulates the binding activity of nuclear factor-kappa B and stimulatory protein-1.

The carotenoid lycopene has been associated with decreased risks of several types of cancer, such as hepatoma. Although lycopene has been shown to inhibit metastasis, its mechanism of action is poorly understood. Here, we used SK-Hep-1 cells (from a human hepatoma) to test whether lycopene exerts its anti-invasion activity via down-regulation of the expression of matrix metalloproteinase (MMP)-9, an important enzyme in the degradation of basement membrane in cancer invasion. The activity and expressions of MMP-9 protein and mRNA were detected by gelatin zymography, Western blotting and RT-PCR, respectively. The binding abilities of nuclear factor-kappa B (NF-kappaB), activator protein-1 and stimulatory protein-1 (Sp1) to the binding sites in the MMP-9 promoter were measured by the electrophoretic mobility shift assay. We showed that lycopene (1-10 microM) significantly inhibited SK-Hep-1 invasion (P<.05) and that this effect correlated with the inhibition of MMP-9 at the levels of enzyme activity (r(2)=.94, P<.001), protein expression (r(2)=.80, P=.007) and mRNA expression (r(2)=.94, P<.001). Lycopene also significantly inhibited the binding abilities of NF-kappaB and Sp1 and decreased, to some extent, the expression of insulin-like growth factor-1 receptor (IGF-1R) and the intracellular level of reactive oxygen species (P<.05). The antioxidant effect of lycopene appeared to play a minor role in its inhibition of MMP-9 and invasion activity of SK-Hep-1 cells because coincubation of cells with lycopene plus hydrogen peroxide abolished the antioxidant effect but did not significantly affect the anti-invasion ability of lycopene. Thus, lycopene decreases the invasive ability of SK-Hep-1 cells by inhibiting MMP-9 expression and suppressing the binding activity of NF-kappaB and Sp1. These effects of lycopene may be related to the down-regulation of IGF-1R, while the antioxidant activity of lycopene appears to play a minor role.

J Nutr Biochem. 2007 Jul;18(7):449-56

Looking older: fibroblast collapse and therapeutic implications.

Skin appearance is a primary indicator of age. During the last decade, substantial progress has been made toward understanding underlying mechanisms of human skin aging. This understanding provides the basis for current use and new development of antiaging treatments. Our objective is to review present state-of-the-art knowledge pertaining to mechanisms involved in skin aging, with specific focus on the dermal collagen matrix. A major feature of aged skin is fragmentation of the dermal collagen matrix. Fragmentation results from actions of specific enzymes (matrix metalloproteinases) and impairs the structural integrity of the dermis. Fibroblasts that produce and organize the collagen matrix cannot attach to fragmented collagen. Loss of attachment prevents fibroblasts from receiving mechanical information from their support, and they collapse. Stretch is critical for normal balanced production of collagen and collagen-degrading enzymes. In aged skin, collapsed fibroblasts produce low levels of collagen and high levels of collagen-degrading enzymes. This imbalance advances the aging process in a self-perpetuating, never-ending deleterious cycle. Clinically proven antiaging treatments such as topical retinoic acid, carbon dioxide laser resurfacing, and intradermal injection of cross-linked hyaluronic acid stimulate production of new, undamaged collagen. Attachment of fibroblasts to this new collagen allows stretch, which in turn balances collagen production and degradation and thereby slows the aging process. Collagen fragmentation is responsible for loss of structural integrity and impairment of fibroblast function in aged human skin. Treatments that stimulate production of new, nonfragmented collagen should provide substantial improvement to the appearance and health of aged skin.

Arch Dermatol. 2008 May;144(5):666-72

Estrogen and skin. An overview.

As the population of postmenopausal women increases, interest in the effects of estrogen grows. The influence of estrogen on several body systems has been well-documented; however, one area that has not been explored is the effects of estrogen on skin. Estrogen appears to aid in the prevention of skin aging in several ways. This reproductive hormone prevents a decrease in skin collagen in postmenopausal women; topical and systemic estrogen therapy can increase the skin collagen content and therefore maintain skin thickness. In addition, estrogen maintains skin moisture by increasing acid mucopolysaccharides and hyaluronic acid in the skin and possibly maintaining stratum corneum barrier function. Sebum levels are higher in postmenopausal women receiving hormone replacement therapy. Skin wrinkling also may benefit from estrogen as a result of the effects of the hormone on the elastic fibers and collagen. Outside of its influence on skin aging, it has been suggested that estrogen increases cutaneous wound healing by regulating the levels of a cytokine. In fact, topical estrogen has been found to accelerate and improve wound healing in elderly men and women. The role of estrogen in scarring is unclear but recent studies indicate that the lack of estrogen or the addition of tamoxifen may improve the quality of scarring. Unlike skin aging, the role of endogenous and exogenous estrogen in melanoma has not been well established.

Am J Clin Dermatol. 2001;2(3):143-50

Chemistry and biotechnology of carotenoids.

Carotenoids are one of the most widespread groups of pigments in nature and more than 600 of these have been identified. Beside provitamin A activity, carotenoids are important as antioxidants and protective agents against various diseases. They are isoprenoids with a long polyene chain containing 3 to 15 conjugated double bonds, which determines their absorption spectrum. Cyclization at one or both ends occurs in hydrocarbon carotene, while xanthophylls are formed by the introduction of oxygen. In addition, modifications involving chain elongation, isomerization, or degradation are also found. The composition of carotenoids in food may vary depending upon production practices, post-harvest handling, processing, and storage. In higher plants they are synthesized in the plastid. Both mevalonate dependent and independent pathway for the formation of isopentenyl diphosphate are known. Isopentenyl diphosphate undergoes a series of addition and condensation reactions to form phytoene, which gets converted to lycopene. Cyclization of lycopene either leads to the formation of β-carotene and its derivative xanthophylls, β-cryptoxanthin, zeaxanthin, antheraxanthin, and violaxanthin or α-carotene and lutein. Even though most of the carotenoid biosynthetic genes have been cloned and identified, some aspects of carotenoid formation and manipulation in higher plants especially remain poorly understood. In order to enhance the carotenoid content of crop plants to a level that will be required for the prevention of diseases, there is a need for research in both the basic and the applied aspects.

Crit Rev Food Sci Nutr. 2010 Sep;50(8):728-60

Carotenoids and human health.

Oxidative stress is an important contributor to the risk of chronic diseases. Dietary guidelines recommend increased consumption of fruits and vegetables to combat the incidence of human diseases such as cancer, cardiovascular disease, osteoporosis and diabetes. Fruits and vegetables are good sources of antioxidant phytochemicals that mitigate the damaging effect of oxidative stress. Carotenoids are a group of phytochemicals that are responsible for different colors of the foods. They are recognized as playing an important role in the prevention of human diseases and maintaining good health. In addition to being potent antioxidants some carotenoids also contribute to dietary vitamin A. There is scientific evidence in support of the beneficial role of phytochemicals in the prevention of several chronic diseases. Although the chemistry of carotenoids has been studied extensively, their bioavailability, metabolism and biological functions are only now beginning to be investigated. Recent interest in carotenoids has focused on the role of lycopene in human health. Unlike some other carotenoids, lycopene does not have pro-vitamin A properties. Because of the unsaturated nature of lycopene it is considered to be a potent antioxidant and a singlet oxygen quencher. This article will review carotenoids in general and lycopene in particular for their role in human health.

Pharmacol Res. 2007 Mar;55(3):207-16

The role of phytonutrients in skin health.

Photodamage is known to occur in skin with exposure to sunlight, specifically ultraviolet (UV) radiation. Such damage includes inflammation, oxidative stress, breakdown of the extracellular matrix, and development of cancer in the skin. Sun exposure is considered to be one of the most important risk factors for both nonmelanoma and melanoma skin cancers. Many phytonutrients have shown promise as photoprotectants in clinical, animal and cell culture studies. In part, the actions of these phytonutrients are thought to be through their actions as antioxidants. In regard to skin health, phytonutrients of interest include vitamin E, certain flavonoids, and the carotenoids, β-carotene, lycopene and lutein.

Nutrients. 2010 Aug;2(8):903-28

Lycopene in tomatoes: chemical and physical properties affected by food processing.

Lycopene is the pigment principally responsible for the characteristic deep-red color of ripe tomato fruits and tomato products. It has attracted attention due to its biological and physicochemical properties, especially related to its effects as a natural antioxidant. Although it has no provitamin A activity, lycopene does exhibit a physical quenching rate constant with singlet oxygen almost twice as high as that of beta-carotene. This makes its presence in the diet of considerable interest. Increasing clinical evidence supports the role of lycopene as a micronutrient with important health benefits, because it appears to provide protection against a broad range of epithelial cancers. Tomatoes and related tomato products are the major source of lycopene compounds, and are also considered an important source of carotenoids in the human diet. Undesirable degradation of lycopene not only affects the sensory quality of the final products, but also the health benefit of tomato-based foods for the human body. Lycopene in fresh tomato fruits occurs essentially in the all-trans configuration. The main causes of tomato lycopene degradation during processing are isomerization and oxidation. Isomerization converts all-trans isomers to cis-isomers due to additional energy input and results in an unstable, energy-rich station. Determination of the degree of lycopene isomerization during processing would provide a measure of the potential health benefits of tomato-based foods. Thermal processing (bleaching, retorting, and freezing processes) generally cause some loss of lycopene in tomato-based foods. Heat induces isomerization of the all-trans to cis forms. The cis-isomers increase with temperature and processing time. In general, dehydrated and powdered tomatoes have poor lycopene stability unless carefully processed and promptly placed in a hermetically sealed and inert atmosphere for storage. A significant increase in the cis-isomers with a simultaneous decrease in the all-trans isomers can be observed in the dehydrated tomato samples using the different dehydration methods. Frozen foods and heat-sterilized foods exhibit excellent lycopene stability throughout their normal temperature storage shelf life. Lycopene bioavailability (absorption) can be influenced by many factors. The bioavailability of cis-isomers in food is higher than that of all-trans isomers. Lycopene bioavailability in processed tomato products is higher than in unprocessed fresh tomatoes. The composition and structure of the food also have an impact on the bioavailability of lycopene and may affect the release of lycopene from the tomato tissue matrix. Food processing may improve lycopene bioavailability by breaking down cell walls, which weakens the bonding forces between lycopene and tissue matrix, thus making lycopene more accessible and enhancing the cis-isomerization. More information on lycopene bioavailability, however, is needed. The pharmacokinetic properties of lycopene remain particularly poorly understood. Further research on the bioavalability, pharmacology, biochemistry, and physiology must be done to reveal the mechanism of lycopene in human diet, and the in vivo metabolism of lycopene. Consumer demand for healthy food products provides an opportunity to develop lycopene-rich food as new functional foods, as well as food-grade and pharmaceutical-grade lycopene as new nutraceutical products. An industrial scale, environmentally friendly lycopene extraction and purification procedure with minimal loss of bioactivities is highly desirable for the foods, feed, cosmetic, and pharmaceutical industries. High-quality lycopene products that meet food safety regulations will offer potential benefits to the food industry.

Crit Rev Food Sci Nutr. 2000 Jan;40(1):1-42

Chemistry, distribution, and metabolism of tomato carotenoids and their impact on human health.

Recent epidemiological studies have suggested that the consumption of tomatoes and tomato-based food products reduce the risk of prostate cancer in humans. This protective effect has been attributed to carotenoids, which are one of the major classes of phytochemicals in this fruit. The most abundant carotenoid in tomato is lycopene, followed by phytoene, phytofluene, zeta-carotene, gamma-carotene, beta-carotene, neurosporene, and lutein. The distribution of lycopene and related carotenoids in tomatoes and tomato-based food products has been determined by extraction and high-performance liquid chromatography-UV/Visible photodiode array detection. Detailed qualitative and quantitative analysis of human serum, milk, and organs, particularly prostate, have revealed the presence of all the aforementioned carotenoids in biologically significant concentrations. Two oxidative metabolites of lycopene, 2,6-cyclolycopene-1,5-diols A and B, which are only present in tomatoes in extremely low concentrations, have been isolated and identified in human serum, milk, organs (liver, lung, breast, liver, prostate, colon) and skin. Carotenoids may also play an important role in the prevention of age-related macular degeneration, cataracts, and other blinding disorders. Among 25 dietary carotenoids and nine metabolites routinely found in human serum, mainly (3R,3'R,6'R)-lutein, (3R,3'R)-zeaxanthin, lycopene, and their metabolites were detected in ocular tissues. In this review we identified and quantified the complete spectrum of carotenoids from pooled human retinal pigment epithelium, ciliary body, iris, lens, and in the uveal tract and in other tissues of the human eye to gain a better insight into the metabolic pathways of ocular carotenoids. Although (3R,3'R,6'R)-lutein, (3R,3'R)-zeaxanthin, and their metabolites constitute the major carotenoids in human ocular tissues, lycopene and a wide range of dietary carotenoids have been detected in high concentrations in ciliary body and retinal pigment epithelium. The possible role of lycopene and other dietary carotenoids in the prevention of age-related macular degeneration and other eye diseases is discussed.

Exp Biol Med (Maywood). 2002 Nov;227(10):845-51

A simple and rapid method to assess lycopene in multiple layers of skin samples.

Topical application of lycopene is a convenient way to restore antioxidants depleted from the skin by UV radiation and achieve protection against premature aging and cancer. In this study, a simple, rapid and reproducible method to quantify lycopene in different skin layers was developed, validated and employed to assess this compound after skin penetration studies. Lycopene was extracted from the stratum corneum (SC) and viable epidermis and dermis (ED) by vortex homogenization and bath sonication in a mixture of acetonitrile and methanol (52:48, v/v). Lycopene was assayed by HPLC using a C(18) column, and acetonitrile:methanol (52:48, v/v) as mobile phase. The quantification limit of lycopene in samples of SC and ED was 35 ng/mL and the assay was linear from 35 to 2,000 ng/mL. Within-day and between-days assays coefficients of variation and relative errors (indicative of precision and accuracy) were less than 15% (or 20% for the limit of quantification). Lycopene recovery from SC and ED was dependent on the spiked concentration: for 50 ng/mL, recoveries were 88.3 and 90.5%; for 100-1,000 ng/mL, recoveries were 68.6-74.9%. This method has a potential application for lycopene quantification during formulation development and evaluation in the dermatological field.

Biomed Chromatogr. 2010 Feb;24(2):154

Lycopene oxidation product enhances gap junctional communication.

Carotenoids as well as their metabolites and oxidation products stimulate gap junctional communication (GJC) between cells, which is thought to be one of the protective mechanisms related to cancer-preventive activities of these compounds. Increased intake of lycopene by consumption of tomatoes or tomato products has been epidemiologically associated with a diminished risk of prostate cancer. Here, we report a stimulatory effect of a lycopene oxidation product on GJC in rat liver epithelial WB-F344 cells. The active compound was obtained by complete in vitro oxidation of lycopene with hydrogen peroxide/osmium tetroxide. For structural analysis high performance liquid chromatography, gas chromatography coupled with mass spectrometry, ultraviolet/visible-, and infrared spectrophotometry were applied. The biologically active oxidation product was identified as 2,7,11-trimethyl-tetradecahexaene-1,14-dial. The present data indicate a potential role of lycopene degradation products in cell signaling enhancing cell-to-cell communication via gap junctions.

Food Chem Toxicol. 2003 Oct;41(10):1399-407