Tomato-Based Products and Lycopene in the Prevention of Cancer: Bioavailability and Antioxidant Properties
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CANCER PREVENTION RESEARCH □ REVIEW ARTICLE □ Tomato-based Products and Lycopene in the Prevention of Cancer: Bioavailability and Antioxidant Properties Eun-Sun Hwang School of Agricultural Biotechnology and Center for Agricultural Biomaterials, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-742, Korea Epidemiological studies showed that dietary intakes of tomatoes and tomato products are associated with a decreased risk of chronic diseases, such as cancer and cardiovascular disease. This beneficial effect could be related to a high intake of carotenoids such as lycopene or β-carotene. Lycopene is present in tomatoes and tomato products and it is one of the most potent antioxidants among dietary carotenoids. Serum and tissue lycopene levels have been found to be inversely related to the incidence of several types of cancer, including prostate cancer. Although the antioxidant properties of lycopene are thought to be primarily responsible for its beneficial effects, evidence is accumulating to suggest that other mechanisms may also be involved. The bioavailability of lycopene is an essential requirement to sustain its in vivo role. This review outlined the characteristics of lycopene and its bioavailability in human body. (Cancer Prev Res 10, 81-88, 2005) ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ Key Words: Tomato, Lycopene, Carotenoids, Bioavailability, Antioxidant, Cancer prevention of vitamin A.2) The ability to function as a provitamin A was INTRODUCTION limited to those carotenoids with an unsubstituted β-ionone group, and include α-carotene, β-carotene, and β-cryptoxan- Carotenoids are the most common natural pigments and thin. Lycopene lacks the β-ionone ring structure of β-carotene more than 600 different compounds have been characterized and it dose not have provitamin A activity. However, together until now. They are responsible for many of the red, orange, with α- and β-carotene it belongs to the class of hydrocarbon and yellow colors of plant leaves, fruits, and flowers, as well carotenoids and contains thirteen double bonds, eleven of which as the colors of some birds, insects, fish, and crustaceans. Only are conjugated.3) Lycopene owes its red color to its extensively plants, bacteria, fungi, and algae can synthesize carotenoids, conjugated polyene structure. In contrast to α-carotene, β- but many animals incorporate them from their diet. Caro- carotene and lutein/zeaxanthin, which are widely distributed tenoids can act as light absorbing pigments in photosynthesis among a great variety of fruits and vegetables, lycopene occurs and protect plants against photosensitization.1) In the early in our diet predominantly in tomatoes and tomato products. 30’s, it became apparent that some of the carotenoids could The popular dishes are pizza and spaghettie with tomato sauce. replace vitamin A in animal diets, and this was followed by Because of the frequency of consumption, tomato ketchup is the realization that some carotenoids were metabolic precursors also a major contributor of lycopene in the diet. The other 책임저자:황은선, ꂕ 151-742, 서울시 관악구 신림동 산 56-1 Correspondence to:Eun-Sun Hwang 서울대학교 농업생명과학대학 농업생물신소재연구소 School of Agricultural Biotechnology and Center for Agricultural Bioma- Tel: 02-880-4889, Fax: 02-873-5260 terials, College of Agriculture and Life Sciences, Seoul National University, E-mail: [email protected] San 56-1 Sillim-dong, Gwanak-gu, Seoul 151-742, Korea Tel: +82-2-880-4889, Fax: +82-2-873-5260 E-mail: [email protected] 81 82 Cancer Prevention Research Vol. 10, No. 2, 2005 ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ sources of dietary lycopene are from watermelon, pink grape- Miller et al13) used 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic fruit, and papaya.4,5) Table 1 illustrates lycopene content of acid diammonium salt (ABTS) as a radical source to study the tomato products. Tomatoes and tomato products also contain interaction of carotenoids with free radicals. Lycopene was the low amount of α-, β-, γ-, δ-carotene, and lutein.6,7) Toma- most efficient scavenger of the ABTS-radical. The radical toes contain about 30 mg lycopene/kg raw fruit;8) even higher scavenging effect of lycopene exceeded that of trolox, a amounts are found in some of the tomato products, e.g., in water-soluble analog of vitamin E, by a factor of three. tomato juice up to 150 mg lycopene/l or in tomato ketchup Ribaya-Mercado et al14) also suggested protective effects of about 100 mg/kg. However, the lycopene content in concen- lycopene toward oxidative stress. When skin was subjected to trated tomato products is generally lower than expected, resul- UV light stress, more skin lycopene was destroyed than β- ting from losses during food processing.8,9) carotene. Recently, two intervention studies found that lycopene may ANTIOXIDANT ACTIVITY OF LYCOPENE protect healthy humans from oxidative damage. Rao et al15) gave placebo, spaghetti sauce (20.5 and 39.2 mg lycopene), Lycopene is the most efficient singlet oxygen quencher of the tomato juice (50.4 mg lycopene), and tomato oleoresin (75 and natural carotenoids exhibiting a higher quenching rate constant 150 mg) to 19 healthy subjects for 1 week each with a one than the other C-40 carotenoids. Ukai et al10,11) found that week washout between each intervention. Serum lycopene irradiation of lycopene in the presence of methylene blue as levels consistently increased after each intervention, while a sensitizer and atmospheric oxygen led to the formation of serum thiobacbituric acid reactive species (TBARS) were re- 2-methyl-2-hepten-6-one and apo-6-lycopenal. These decompo- duced by 20% (tomato juice) and by 23% (20.5 mg lycopene sition products also might possess biological activities as has in spaghetti sauce). Although not statistically significant, a been described for apocarotenals formed from β-carotene as trend toward lowered serum protein thiols and lymphocyte precursors of retinal. Numerous in vitro and in vivo studies have 8-hydroxydeoxyguanosine/deoxyguanosine (8-OHdG/dG) ratios examined the antioxidant activity of lycopene. Wagner et al12) were observed. Riso et al16) gave either 16.5 mg of lycopene used methylene as a sensitizer to study the consumption of as tomato puree or a tomato-free diet to 5 healthy subjects carotenoids during photooxidation of human plasma and low- in each group for 21 days. DNA damage (assessed by ex vivo density lipoprotein (LDL). Lycopene and β-carotene were more treatment of H2O2 using the Comet assay) decreased by 33% resistant to photooxidation in blood plasma than lutein and in tomato puree group after a 21-day intervention compared zeaxanthin. Upon exposure of blood plasma to a water-soluble to tomato-free diet group. However, several studies have shown singlet oxygen generator, the levels of the lipophilic antioxidant inconsistent results. Franke et al17) assessed serum TBARS in lycopene, β- carotene, and α-tocopherol remained unchanged. nine healthy volunteers in relation to serum carotenoid and The data suggest that lycopene may contribute to the tocopherols concentrations. Whereas (α-tocopherol, α- and β- prevention of lipid peroxidation via singlet oxygen quenching. carotene were significantly inversely related to TBARS, α- tocopherol and lycopene were not. Morrow et al18) also found that the plasma concentration of F2-isoprostanes, prostaglandin Table 1. Lycopene content of tomato products F2-like compounds produced by peroxidation of arachidonic ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ lycopene Lycopene acid, were not related to serum lycopene concentration in Product Serving size (mg/100 g) (mg/serving) smokers. In conclusion, lycopene is commonly located in cell ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ Tomato juice 9.5 250 ml (1 cup) 25 membranes, more specifically in the hydrophobic areas such as Tomato ketchup 15.9 15 ml (1 tsp) 2.7 the inner core. There it may influence the physical properties Spaghetti sauce 21.9 125 ml (1/2 cup) 28.1 of the membrane such as thickness, strength, and fluidity. Tomato paste 42.2 30 ml (2 tsp) 13.8 Reaction of lycopene with ROS may be restricted in the Tomato soup 7.2 250 ml (prepared) 9.7 hydrophobic inner part of the membrane. (condensed) Tomato sauce 14.1 60 ml (1/4 cup) 8.9 ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ Eun-sun Hwang:Tomato-based Products and Lycopene Prevention of Cancer 83 ꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏꠏ tenoids in human plasma. In a Japanese study of 923 sub- ABSORPTION OF LYCOPENE jects,25) significantly higher lycopene, β- and α-carotene serum levels were detected in women than in men. Serum lycopene Absorption of lycopene is affected by several biological and levels were found to decrease with age.21,26) In addition, lifestyle factors. Lycopene first need to be released from their lycopene levels are correlated to non-HDL cholesterol in the food matrices and solublized the gut in the presence of fat and plasma.26) The consumption of alcohol appears to have no effect conjugated bile acids.19∼21) In the small intestine, ingested on lycopene plasma levels.27) lycopene is incorporated into micelles formed from fat and bile Surprisingly, no increases in lycopene serum levels were acids. This facilitates absorption into intestinal mucosa cell, a observed after a single dose of a large quantity