Lycopene protective effects

It was observed that people with low carotenoid intake or low blood levels have an increased risk of degenerative diseases. In a number of these diseases free radical damage plays a role in the pathophysiology of the disease. Earlier studies were focused mainly on p-carotene and the lycopene protective effect against prostate and lung cancer, but there is as yet no definitive proof for a causal relationship or for a beneficial antioxidant effect of carotenoids. 

Fruifs and vegetables also contain ofher bioactive substances such as polyphenols (including well-known pigments anthocyanins, flavonols) and non-provitamin A carotenoids (mainly lycopene, lutein, and zeaxanthin) that may have protective effects on chronic diseases. Polyphenols and carotenoids are known to display antioxidant activities, counteracting oxidative alterations in cells. Besides these antioxidant properties, these colored bioactive substances may exert other actions on cell signaling and gene expression. 

Some prospective and case-control studies also investigated the relationship of carotenoids and the evolution of CCA-IMT. Although the EVA study showed no association between total carotenoids and IMT, others like the ARIC study, the Los Angeles Atherosclerosis Study, " and the Kuopio Ischaemic Heart Disease Risk Factor Study demonstrated the protective role of isolated carotenoids such as lycopene, lutein, zeaxanthin, and P-cryptoxanthin on IMT. Thus, findings from prospective and case-control studies have suggested that some carotenoids such as lycopene and P-carotene may present protective effects against CVD and particularly myocardial infarcts and intima media thickness, a marker of atherosclerosis. 

Epidemiological data on carotenoids and cerebral infarcts or strokes indicate a protective effect of P-carotene and lycopene. Indeed, the Basel prospective study, the Kuopio Ischaemic Heart Disease Risk Factor study, and the Physicians Health Study " have shown an inverse correlation between carotenoid plasma level and risk of stroke. In the same way, Hirvonen et al. demonstrated, in findings from the ATBC cancer prevention stndy, an inverse association between P-carotene dietary intake and stroke. However, clinical data on carotenoids and stroke are nonexistent and they are needed to confirm this possible protective effect of carotenoids on stroke. 

Kim, H.S. and Lee, B.M., Protective effects of antioxidant supplementation on plasma lipid peroxidation in smokers, J. Toxicol. Environ. Health A, 63, 583, 2001. Gaziano, J.M. et al.. Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation. Atherosclerosis, 112, 187, 1995. Sutherland, W.H.F. et al.. Supplementation with tomato juice increases plasma lycopene but does not alter susceptibility to oxidation of low-density lipoproteins from renal transplant recipients, Clin. Nephrol, 52, 30, 1999. 

Matos, HR, P Di Mascio, and MHG Medieros. 2000. Protective effect of lycopene on lipid peroxidation and oxidative DNA damage in cell culture. Arch Biochem Biophys 383(1) 56—59. 

Lycopene had a protective effect on the oxidative stress-mediated damage of the human skin after irradiation with UV light (Ribaya-Mercado and others 1995). 

Low bone density is also associated with oxidative stress in lower species. Thus, in ovariectomized rats melatonin has a bone-protective effect, which depends in part on its free radical-scavenging properties (Cardinali et al., 2003). A mouse model that has been used to study the role of ROS in age-related disorders including osteoporosis is the accelerated mouse-senescence-prone P/2 (SAM-P/2) that generates increased oxygen radicals (Hosokawa, 2002 Udagawa, 2002). This model could be very useful in studying the role of lycopene in osteoporosis. 

A study on the photoprotective effect of the topical application of 2% vitamin E and 5% vitamin C in humans showed no effect with the application of each substance alone, but an enhanced photo-protective effect after applying vitamins E and C combined, which was attributed to the regeneration of vitamin E by vitamin C.20 This enhanced effect has also been shown with the topical application of a combination of 15% ascorbic acid and 1% a-tocopherol to porcine skin.21 The combined systemic supplementation of vitamins C and E was similarly able to reduce sunburn reactions22 and to increase the minimal erythema dose (MED), a measure for individual photosensitivity, more than supplementation with either vitamin E or vitamin C alone.23,24 An oral supplementation with an anti-oxidative combination of carotenoids (P-carotene and lycopene), vitamin C, vitamin E, selenium, and proanthocyanidins (Seresis , Pharmaton SA, Lugano, Switzerland) also reduced the development and grade of UVB-induced erythema 25... 

In spite of the protective effect of several antioxidant enzymes and metal-binding proteins, free radicals are still widely prevalent. Thus, Ames et al. (A 10) estimated that in each rat cell there are 100,000 radical hits each day, while in every human cells there are 10,000/day. Importantly, there are numerous natural free radical scavengers/chain breakers, the most notable being vitamins C andE, various carotenoids (beta-carotene, lycopene, etc.), flavonoids (rutin, quercetin, catechin, etc.), uric acid, and bilirubin, among others (Table 2). 

Lycopene has been reported to increase the survival rate of mice exposed to x-ray radiation (Forssberg et al., 1959). Ribaya-Mercado et al. (1995) reported on the protective effects of lycopene toward oxidative stress-mediated damage of the human skin upon irradiation with UV light. Peng et al. (1998) examined the levels of different carotenoids, including lycopene, and vitamins A and E in plasma and cervical tissues obtained from 87 women subjects (27 cancerous, 33 precancerous and 27 noncancerous). Women with cancer had lower plasma levels of lycopene, other carotenoids, vitamin A and E compared to pre- and noncancerous women. The... 

Two prospective studies from Finland demonstrate that low levels of plasma lycopene, resulting from a diet low in tomatoes, significantly increase the risk for heart attack, stroke, and early atherosclerosis among middle-aged men [57, 58]. Similarly, a Dutch study revealed a lowered risk for aortic calcification in current and former smokers with higher lycopene plasma concentrations [59]. Finally, results from a European multicenter case control study (EURAMIC) are suggestive of a protective effect of lycopene against myocardial infarction [60]. 

Cell culture and animal experiments offer further evidence of the protective effect of lycopene against DNA oxidation. In cell culture, lycopene supplementation decreased levels of both 8-OHdG and lipid peroxidation induced by FeNTA/ascorbate [82]. Subsequently, this effect was also demonstrated in vivo. Rats treated with ferric... 

To date, only eight studies in animal models have been pubhshed on the cancer chemopreventive effects of lycopene or tomato carotenoids (Table 32.3), with the majority showing a protective effect of lycopene. A positive correlation between lycopene or tomato product intake and cancer... 

Indeed, the red pigment occurs in tomatoes. When it s actually inside the tomato, protecting the fruit from disease and sun damage, this molecule is in a form called trans-lycopene. But in order for our bodies to absorb it well, it needs to be in a form called cis-lycopene. To effect this conversion, tomatoes must be cooked. 

Lycopene has been shown to inhibit the incidence and growth of the chemically induced breast tumors in laboratory animal studies [12, 107]. A protective effect of lycopene was found on DMBA-induced rat mammary tumors. When compared with placebo or control rats, the lycopene fed rats had the smallest average size of tumors, but the difference was not statistically significant. The number of tumors that developed over 135 days was much lower in the... 

Cl, 0.13-0.39 for the highest quartile of intake). Lycopene was also strongly associated with a reduced risk of 0.22 (95% Cl, 0.13-0.37). Adjustment of tomato intake for several phytochemicals explained almost completely its protective effect, which disappears in this model. 

Karimi G, Ramezani M, Abdi A (2005) Protective effects of lycopene and tomato extract against doxorubicin-induced cardiotoxicity. Phytother Res 19 912-914... 

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