Natural Carotenoids

B. Antioxidant Properties

• 1. Antioxidant activity of palm oil carotene in peroxyl radical- mediated peroxidation of phosphatidyl choline liposomes

  Britton, G. & Farombui, EO. (1999). Antioxidant activity of palm oil carotene in peroxyl radical- mediated peroxidation of phosphatidyl choline liposomes. Redox Rep. 4(1-2):61-8.

  The antioxidant efficacy of alpha-carotene and comparison with beta-carotene in multilamellar liposomes prepared from egg yolk phosphatidyl choline (EYPC) exposed to the lipid soluble 2,2'-azobis (2,4-dimethyl valeronitrile) (AMVN) was investigated. Lipid peroxidation was measured as thiobarbituric acid reacting substances (TBARS) at 532 nm or as hydroperoxide formation at 234 nm after separation of phosphatidyl choline hydroperoxide (PCOOH) by high-pressure liquid chromatography (HPLC). Lutein and zeaxanthin, the hydroxyl derivatives of alpha- and beta-carotenes, and the chain breaking antioxidant alpha-tocopherol were also included in the study. AMVN being a lipid soluble, non polar azo initiator penetrates into the hydrophobic interior of the phospholipid bilayer, forming peroxyl radicals which peroxidate the phospholipid leading to PCOOH accumulation. All the carotenoids tested at 1 mol% relative to EYPC significantly suppressed the formation of PCOOH compared to control samples. In this system, alpha-carotene retarded PCOOH formation better than beta-carotene. Similarly, lutein was a better antioxidant than is zeaxanthin. But lutein and zeaxanthin were more effective antioxidants than alpha- and beta-carotenes, respectively. After 1 h of incubation of the carotenoid with AMVN, alpha-, beta-carotene, lutein and zeaxanthin limited PCOOH formation by 77%, 68%, 85% and 82%, respectively, while alpha-tocopherol elicited 90% reduction. AMVN incubated with EYPC for 2 h induced the formation of TBARS compared to control (P < 0.001). alpha-Carotene significantly suppressed the TBARS formation by 78% whilst beta-carotene, lutein, zeaxanthin and alpha-tocopherol elicited 60%, 91% and 80% reductions, respectively. Increasing the concentration of the carotenoid > 1 mol% to EYPC did not significantly increase protection of the membrane against free radical attack. Our findings suggest that alpha-carotene is a better antioxidant than is beta-carotene in phosphatidyl choline vesicles. It may, therefore, be useful in limiting free radical mediated peroxidative damage against membrane phospholipids in vivo.

• 2. Carotenoids mixtures protect multilamellar liposomed against oxidative damage : synergistic effects of lycoepene and lutein

  Sies, H. et al. (1998). Carotenoids mixtures protect multilamellar liposomed against oxidative damage : synergistic effects of lycoepene and lutein. FEBS Lett. 427(2):305-8.

  Antioxidant activity of carotenoids in multilamellar liposomes assayed by inhibition of formation of thiobarbituric acid-reactive substances was in the ranking: lycopene> alpha-tocopherol > alpha-carotene > beta-cryptoxanthin > zeaxanthin = beta-carotene > lutein. Mixtures of carotenoids were more effective than the single compounds. This synergistic effect was most pronounced when lycopene or lutein was present. The superior protection of mixtures may be related to specific positioning of different carotenoids in membranes.

• 3. Feeding mice palm carotene prevents DNA damage in bone marrow and reduction of peripheral leukocyte counts and enhances survival following X-Ray irradiations

  Umegaki, K. et al. (1997). Feeding of palm oil carotene to mice prevents chromosomal damage in bone marrow and reduction of white blood cell counts and enhances urvival following x-ray irradiation”, Poster presented at the International Society for Fat Annual Symposium. 18(10):1943-7.

  This study examined the effects of palm carotene feeding on DNA damage of bone marrow, recovery of peripheral leukocyte counts, and the survival of mice that received whole-body X-ray irradiation. The palm carotene was composed of alpha- and beta-carotene in a ratio of 1:3. Mice were fed either a basal diet or a carotene diet (50 mg carotene/100 g diet) for 2 weeks, then irradiated. The carotene diet was prepared by the dietary protocol that markedly enhanced the accumulation of carotene in tissues (J. Nutr. 125, 3081, 1995). DNA damage in bone marrow was evaluated by micronucleus assay using peripheral blood. When mice received X-ray (1.5 Gy), marked DNA damage in bone marrow and reduction of peripheral leukocyte count were observed. These changes were significantly attenuated in mice fed the carotene diet. In addition, X-ray (6.5 Gy)-induced survival of mice fed the carotene diet was higher than those fed the basal diet. In mice fed the carotene diet, alpha- and beta-carotene were detected in bone marrow and liver, and concentration of vitamin A in liver was about four times higher compared with that in mice fed the basal diet. These findings suggest that feeding mice palm carotene prevents radiation-induced damages by way of its antioxidant activity and/or vitamin A activity.

• 4. The antioxidant effect of palm fruit carotene on skin lipid peroxidation in guinea pigs as estimated by chemiluminescence-HPLC method

  Miyazawa, T. et al.(1994). The antioxidant effect of palm fruit carotene on skin lipid peroxidation in guinea pigs as estimated by chemiluminescence-HPLC method. Journal of Nutritional Science and Vitamology. 40(4):315-24.

  To study the antioxidant effect of palm fruit carotene on skin lipid peroxidation, the guinea pigs were orally fed ad libitum palm fruit carotene, beta-carotene, or vehicle emulsions, in which carotene (0.05%, w/w) was suspended in drinking water. After treatment of carotene for 12 weeks, animals were exposed to ultraviolet ray (UV), and squalene monohydroperoxide (SqOOH)/squalene (Sq) ratios in the skin lipid were analyzed using the chemiluminescence-HPLC method. Carotene accumulation was found in the skin of guinea pigs that were orally administered palm fruit carotene or beta-carotene. After UV irradiation, especially immediately after, the rise in the SqOOH/Sq ratio was effectively suppressed in both carotene-drinking groups in contrast with the control (carotene-untreated) group. An inverse correlation between the carotene content and the SqOOH/Sq ratio in the skin was also observed. The results suggested that palm fruit carotene intake prevents skin lipid peroxidation caused by UV irradiation.

• 5. Distribution and antioxidant activity of a palm oil carotene in rats

  Packer, L. et al. (1992). Distribution and antioxidant activity of a palm oil carotene in rats. Biochemistry International. 28(5):881-6.

  The aim of this study was to determine the tissue distribution of carotenoids in palm oil and to correlate the accumulation of carotenoids with protection against oxidative stress. We found that: (i) After 2 weeks beta-carotene in the liver increased from 7.3 to 30 ng/g wet tissue; alpha-carotene and lycopene after 10 weeks of feeding were 74 and 49 ng/g wet tissue respectively; (ii) Beta-carotene content in heart and hind limb skeletal muscles increased after 10 weeks to 17 and 6 ng/g wet tissue respectively; (iii) No carotenoids were detected in the brain, adipose and skin during the period of feeding; (iv) After in vitro induction of lipid peroxidation in liver homogenates by an azo-initiator of peroxyl radicals an inverse correlation between tissue carotenoid level and accumulation of lipid peroxidation products was observed; alpha-carotene > lycopene > beta-carotene.

• 6. Effects of palm carotenoids in rat hepatic cytochrome P450-mediated benzo(a)pyrene metabolism

  Tan, B. & Chu, FL. (1991). Effects of palm carotenoids in rat hepatic cytochrome P450-mediated benzo(a)pyrene metabolism. American Journal of Clinical Nutrition. 1071S-1075S.

  Using benzo(a)pyrene (BaP) metabolism as a probe for chemical carcinogenesis, in vitro and in vivo effects of palm-oil carotenoid [beta-carotene (BC), alpha-carotene (AC), or canthaxanthin (CTX)] on BaP metabolism in the rat hepatic cytochrome P450-mediated monooxygenase system were studied. Apparent Michaelis-Menten constants (Km) for formation of the precursor carcinogen, 7,8-dihydrodiol BaP, were found to be 14.4 (BC), 1.74 (AC), and 0.7 (CTX) mumol/L. The order of anticarcinogenic strength established in this study was BC much greater than AC greater than CTX. Increased formation of the detoxification intermediate, 3-hydroxy BaP, with increased carotenoid concentration was observed. The order of detoxification strength was BC greater than AC = CTX. The presence of carotenoids in vivo inhibited BaP metabolism. Using 9,10-dihydrodiol BaP as an indicator for inhibition, the order of the antioxidative activity was palm oil (with carotenoids) greater than BC greater than CTX greater than palm oil (without carotenoids). BC and AC may selectively modify the rat-liver microsomal enzymes, thus providing a biochemical mechanism for the inhibitory effect of palm carotenoids on chemical carcinogenesis.

• 7. Health benefits of a natural carotenoid rich oil: a proposed mechanism of protection against ischaemia/ reperfusion injury.

  Esterhuyse, A. J. et al. (2008). Health benefits of a natural carotenoid rich oil: a proposed mechanism of protection against ischaemia/ reperfusion injury. Asia Pacific Journal Clinical Nutrition. 17(1): 316-9.

  Numerous studies have reported the protective properties of carotenoid supplementation against skin and eye associated diseases. However, conflicting data concerning the efficacy of beta-carotene in the pathogenesis of cancers and cardiovascular disease exist. It has been shown that beta-carotene is an effective antioxidant on its own or in combination with other antioxidants. Red palm oil (RPO) is a potent anti-oxidant rich oil which consists of carotenoids, tocopherols, tocotrienols and lycopenes as well as lipid fractions such as squalene, saturated and unsaturated fatty acids (which maximize absorption of these anti-oxidants) and Co-enzyme Q10. alpha and beta-carotene account for more than 90% of the total carotene in RPO. It is known that ischaemia/reperfusion-induced injury causes an imbalance in oxygen supply which can lead to oxidative stress in the heart. It has been shown that the mitogen-activated protein kinases (MAPKs), PKB/Akt and the NO-cGMP all play vital roles in ischaemia/reperfusion injury in the heart. Therefore, our review mainly focuses on the signaling pathways involved in functional recovery induced by a natural carotenoid oil after ischaemia/reperfusion injury.

• 8. Modification of lymphocyte DNA damage by carotenoid supplementation in postmenopausal women

  Zhao et al. Am J Clin Nutr. 2006 Jan;83(1):163-9.

  BACKGROUND:

  Oxidative stress has been implicated in the pathogenesis of chronic diseases related to aging such as cancer and cardiovascular disease. Carotenoids could be a part of a protective strategy to minimize oxidative damage in vulnerable populations, such as the elderly.

  OBJECTIVE:

  Our aim was to determine the protective effect of carotenoids against DNA damage.

  DESIGN:

  A randomized, double-blind, placebo-controlled intervention study was conducted. Thirty-seven healthy, nonsmoking postmenopausal women aged 50-70 y were randomly assigned to 1 of 5 groups and were instructed to consume a daily dose of mixed carotenoids (beta-carotene, lutein, and lycopene; 4 mg each), 12 mg of a single carotenoid (beta-carotene, lutein, or lycopene), or placebo for 56 d. Plasma carotenoid concentrations were analyzed by using HPLC, and lymphocyte DNA damage was measured by using a single-cell gel electrophoresis (comet) assay.

  RESULTS:

  At day 57, all carotenoid-supplemented groups showed significantly lower endogenous DNA damage than at baseline (P < 0.01), whereas the placebo group did not show any significant change. Significantly less (P < 0.05) endogenous DNA damage was found as early as day 15 in the mixed carotenoid (P < 0.01) and beta-carotene (P < 0.05) groups.

  CONCLUSIONS:

  The results indicate that carotenoid supplementation decreases DNA damage and that a combination of carotenoids (4 mg each of lutein, beta-carotene, and lycopene), an intake that can be achieved by diet, or a larger dose (12 mg) of individual carotenoids exerts protection against DNA damage.

• 9. Recovery of human lymphocytes from oxidative DNA damage; the apparent enhancement of DNA repair by carotenoids is probably simply an antioxidant effect.

  Torbergsen et al. Eur J Nutr. 2000 Apr;39(2):80-5.

  BACKGROUND:

  Many epidemiological studies have identified a protection against cancer associated with consumption of fruit and vegetables. One factor in this protection may be the enhancement of cellular DNA repair activity by micronutrients, such as carotenoids, found in these foods.

  AIMS OF THE STUDY:

  To measure the capacity of lymphocytes isolated from volunteers supplemented with beta-carotene, lutein or lycopene to recover from DNA damage induced in vitro by treatment with H2O2.

  METHODS:

  Healthy volunteers were given supplements of lutein (15 mg/day), lycopene (15 mg/day) and beta-carotene (15 mg/day), each for 1 week, the supplementation periods being separated by 3-week wash-out periods. Blood samples were taken at the beginning and end of each supplementation, and at 1 week and 3 weeks during the wash-out period. Carotenoid levels were measured in plasma. Lymphocytes were isolated and frozen. Subsequently, they were treated with 100 microM H2O2 and incubated for up to 24 h; DNA damage was measured with the comet assay (single cell gel electrophoresis) after 0, 2, 4, 8 and 24 h.

  RESULTS:

  Increases of 2- to 3-fold in mean plasma lutein and beta-carotene concentrations were seen at the end of the respective supplementation periods; they returned virtually to basal levels after wash-out. Lycopene concentrations were less affected by supplementation, and were more variable. H2O2-induced DNA strand breaks were apparently only slowly rejoined by the lymphocytes. The rejoining of breaks in the first few hours appeared substantially faster in lymphocytes following supplementation with beta-carotene, but no such effect was seen with lutein. In those individuals who showed increases in lycopene concentrations, the recovery was significantly faster. Lymphocytes that were not treated with H2O2 showed a transient increase in DNA breakage to about double the background level in 2 h, presumably as a result of exposure to atmospheric oxygen; this effect, too, was relieved by supplementation with lycopene or beta-carotene.

  CONCLUSIONS:

  While certain carotenoids appear to enhance recovery from oxidative damage, this is probably in fact an antioxidant protective effect against additional damage induced by atmospheric oxygen, rather than a stimulation of DNA repair.

• 10. Bioactivity and protective effects of natural carotenoids.

  Stahl et al. Biochim Biophys Acta. 2005 May 30;1740(2):101-7. Epub 2004 Dec 28.

  Carotenoids comprise a class of natural fat-soluble pigments which are found in numerous fruits and vegetables. The consumption of a diet rich in carotenoids has been epidemiologically correlated with a lower risk for several diseases. The antioxidant activity of carotenoids and biochemical properties influencing signaling pathways have been discussed as basic mechanisms of prevention. Conflicting data from intervention studies with beta-carotene to prevent cancers and cardiovascular disorders have challenged the concept. However, there is convincing evidence that carotenoids are important components of the antioxidant network. Photooxidative damage is suggested to be involved in the pathobiochemistry of several diseases affecting the skin and the eye, and carotenoids may protect light-exposed tissues. Lutein and zeaxanthin are the predominant carotenoids of the retina and are considered to act as photoprotectants preventing retinal degeneration. The unique distribution, localization and high levels of both carotenoids within the macula lutea as well as their physicochemical properties make them suitable candidates for photoprotection. beta-Carotene is used as an oral sun protectant for the prevention of sunburn and has been shown to be effective either alone or in combination with other carotenoids or antioxidant vitamins. Protective effects are also achieved with a diet rich in lycopene.