Lycopene synergistically inhibits LDL oxidation in combination with vitamin E, glabridin, rosmarinic acid, carnosic acid, or garlic

Synergistic effects of phenolics and carotenoids on human low-density lipoprotein oxidation

Low-density lipoprotein oxidation is believed to play an important role in the development of atherosclerosis and therefore a high resistance of LDL against oxidation may prevent atherogenesis and accompanying disorders. Several secondary plant metabolites have been tested for their ability to prevent oxidation of LDL and many phenolics as well as carotenoids have been shown to enhance LDL oxidation resistance. We showed that the quercetingylcoside rutin is able to inhibit copper-induced formation of conjugated dienes and loss of tryptophan fluorescence in LDL. However, enrichment of LDL with the carotenoids lutein or lycopene did not result in an alleviation of LDL oxidation. Since there is an agreement that not one antioxidant alone can lead to health benefits but the combination, as found for example in fruits and vegetables, is the active principle, we tested whether the combination of a phenolic compound (i. e. rutin) and carotenoids (i.e. lutein or lycopene) leads to synergistic effects. Both combinations were shown to exert supra-additive protection of LDL towards oxidation, which is most likely due to different allocation of the antioxidants in the LDL-particle and to different mechanisms of antioxidant action.

Antioxidant Activity of Iranian Echium amoenum Fisch & C.A. Mey Flower Decoction in Humans: A cross-sectional Before/After Clinical Trial

Medicinal plants are recognized as sources of natural antioxidants that can protect from biological system oxidative stress. The present cross-sectional before/after clinical trial was carried out to investigate the antioxidant properties of the decoction of the flowers of Echium amoenum Fisch & C.A. Mey in humans. A group of 38 healthy subjects was invited to use the E. amoenum (7 mg kg(-1)) twice daily for 14 days. Blood samples before and after entering the study were measured for lipid peroxidation level (LPO), total antioxidant capacity (TAC) and total thiol (SH) molecules. A significant reduction of blood LPO (24.65 +/- 11.3 versus 19.05 +/- 9.7, P = 0.029) was observed after 14 days of E. amoenum consumption. Blood TAC (1.46 +/- 0.51 versus 1.70 +/- 0.36, P = 0.018) and total thiol molecules (0.49 +/- 0.11 versus 0.56 +/- 0.12, P = 0.001) increased after 14 days of E. amoenum consumption. In conclusion, this antioxidative stress potential of E. amoenum may be due to its bioactive antioxidant components, especially rosmarinic acid and flavonoids. In recent years the importance of oxidative stress in the pathophysiology of many human disorders has been confirmed, thus use of this plant as a dietary supplement is highly recommended.

Health benefits of herbs and spices: the past, the present, the future

Herbs and spices have a traditional history of use, with strong roles in cultural heritage, and in the appreciation of food and its links to health. Demonstrating the benefits of foods by scientific means remains a challenge, particularly when compared with standards applied for assessing pharmaceutical agents. Pharmaceuticals are small-molecular-weight compounds consumed in a purified and concentrated form. Food is eaten in combinations, in relatively large, unmeasured quantities under highly socialised conditions. The real challenge lies not in proving whether foods, such as herbs and spices, have health benefits, but in defining what these benefits are and developing the methods to expose them by scientific means.

CULTURAL ASPECTS

The place of herbs and spices in the diet needs to be considered in reviewing health benefits. This includes definitions of the food category and the way in which benefits might be viewed, and therefore researched. Research may focus on identifying bioactive substances in herbs and spices, or on their properties as a whole food, and/or be set in the context of a dietary cuisine.

THE ROLE OF HERBS AND SPICES IN HEALTH

The antioxidant properties of herbs and spices are of particular interest in view of the impact of oxidative modification of low-density lipoprotein cholesterol in the development of atherosclerosis. There is level III-3 evidence (National Health and Medical Research Council [NHMRC] levels of evidence) that consuming a half to one clove of garlic (or equivalent) daily may have a cholesterol-lowering effect of up to 9%. There is level III-1 evidence that 7.2 g of aged garlic extract has been associated with anticlotting (in-vivo studies), as well as modest reductions in blood pressure (an approximate 5.5% decrease in systolic blood pressure). A range of bioactive compounds in herbs and spices have been studied for anticarcinogenic properties in animals, but the challenge lies in integrating this knowledge to ascertain whether any effects can be observed in humans, and within defined cuisines. Research on the effects of herbs and spices on mental health should distinguish between cognitive decline associated with ageing and the acute effects of psychological and cognitive function. There is level I and II evidence for the effect of some herbal supplements on psychological and cognitive function. There is very limited scientific evidence for the effects of herbs and spices on type 2 diabetes mellitus, with the best evidence being available for the effect of ginseng on glycaemia, albeit based on four studies. More research is required, particularly examining the effects of chronic consumption patterns. With increasing interest in alternatives to non-steroidal anti-inflammatory agents in the management of chronic inflammation, research is emerging on the use of food extracts. There is level II evidence for the use of ginger in ameliorating arthritic knee pain; however, the improvement is modest and the efficacy of ginger treatment is ranked below that of ibuprofen. More definitive research is required.

PUBLIC HEALTH AND DIETARY IMPLICATIONS

Recommendations for intakes of food in the Australian guide to healthy eating do not yet include suggested intakes of herbs and spices. Future consideration should be given to including more explicit recommendations about their place in a healthy diet. In addition to delivering antioxidant and other properties, herbs and spices can be used in recipes to partially or wholly replace less desirable ingredients such as salt, sugar and added saturated fat in, for example, marinades and dressings, stir-fry dishes, casseroles, soups, curries and Mediterranean-style cooking. Vegetable dishes and vegetarian options may be more appetising when prepared with herbs and spices.

FUTURE DIRECTIONS

As several metabolic diseases and age-related degenerative disorders are closely associated with oxidative processes in the body, the use of herbs and spices as a source of antioxidants to combat oxidation warrants further attention. Immediate studies should focus on validating the antioxidant capacity of herbs and spices after harvest, as well as testing their effects on markers of oxidation. This will work in parallel with clinical trials that are aiming to establish antioxidants as mediators of disease prevention. From a dietary perspective, the functionality of herbs and spices will be exposed through consideration of their properties as foods. As with most foods, the real benefits of including them in the diet are likely to emerge with a better understanding of the attributes of health that are best supported by food, and in methodological developments addressing the evidence base for their effects. These developments are well underway through evidence-based frameworks for substantiating health claims related to foods. At present, recommendations are warranted to support the consumption of foods rich in bioactive components, such as herbs and spices. With time, we can expect to see a greater body of scientific evidence supporting the benefits of herbs and spices in the overall maintenance of health and protection from disease.

Tomatoes versus lycopene in oxidative stress and carcinogenesis: conclusions from clinical trials

OBJECTIVE

To review the effects of tomato product supplementation, containing lycopene, on biomarkers of oxidative stress and carcinogenesis in human clinical trials.

RESULTS

Supplementation of tomato products, containing lycopene, has been shown to lower biomarkers of oxidative stress and carcinogenesis in healthy and type II diabetic patients, and prostate cancer patients, respectively. Processed tomato products like tomato juice, tomato paste, tomato puree, tomato ketchup and tomato oleoresin have been shown to provide bioavailable sources of lycopene, with consequent increases in plasma lycopene levels versus baseline. Dietary fats enhance this process and should be consumed together with food sources of lycopene. The mechanisms of action involve protection of plasma lipoproteins, lymphocyte DNA and serum proteins against oxidative damage, and anticarcinogenic effects, including reduction of prostate-specific antigen, upregulation of connexin expression and overall decrease in prostate tumor aggressiveness. There is limited in vivo data on the health benefits of lycopene alone. Most of the clinical trials with tomato products suggest a synergistic action of lycopene with other nutrients, in lowering biomarkers of oxidative stress and carcinogenesis.

CONCLUSIONS

Consumption of processed tomato products, containing lycopene, is of significant health benefit and can be attributed to a combination of naturally occurring nutrients in tomatoes. Lycopene, the main tomato carotenoid, contributes to this effect, but its role per se remains to be investigated.

Combination chemoprevention of experimental gastric carcinogenesis by s-allylcysteine and lycopene: modulatory effects on glutathione redox cycle antioxidants

Combination chemoprevention by diet-derived agents is a promising strategy for protection against gastric cancer. We therefore evaluated the combined chemopreventive effect of S-allylcysteine (SAC), an organosulfur constituent of garlic, and lycopene, a major carotenoid present in tomatoes, against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and saturated sodium chloride (S-NaCl)-induced gastric carcinogenesis in Wistar rats. The animals were divided into eight groups of six animals each. Rats in group 1 were given MNNG by intragastric intubation on days 0 and 14 as well as S-NaCl every 3 days during weeks 0-3. Animals in groups 2-4, administered MNNG and S-NaCl as in group 1, received in addition SAC and lycopene alone and in combination, respectively, three times per week starting on the day following the first exposure to MNNG. Groups 5-7 were given the chemopreventive agents alone, whereas group 8 served as controls. The animals were sacrificed after an experimental period of 21 weeks. Measurement of lipid peroxidation and antioxidants of the glutathione redox cycle in the stomach, liver, and erythrocytes was used to monitor the chemopreventive potential of SAC and lycopene. In the tumor tissue, diminished lipid peroxidation was accompanied by an increase in reduced glutathione (GSH) and GSH-dependent enzymes, whereas in the liver and erythrocytes, enhanced lipid peroxidation was associated with antioxidant depletion. Although SAC and lycopene alone significantly suppressed the development of gastric cancer, administration of SAC and lycopene in combination was more effective in inhibiting MNNG-induced stomach tumors and modulating the redox status in the tumor and host tissues. The results of the present study validate the hypothesis that diet-derived chemopreventive agents such as SAC and lycopene in combination may interact synergistically with high efficacy and lessened toxicity against gastric cancer.

Combined lycopene and vitamin E treatment suppresses the growth of PC-346C human prostate cancer cells in nude mice

Epidemiologic studies have repeatedly associated a high intake of lycopene and vitamin E with reduced prostate cancer risk. The present study examined the ability of the 2 compounds to reduce tumor growth and prostate-specific antigen (PSA) plasma levels in the PC-346C orthotopic mouse model of human prostate cancer. Three days after intraprostatic tumor injection, NMRI nu/nu mice were administered a daily oral dose of synthetic lycopene [5 or 50 mg/kg body weight (BW)], vitamin E in the form of alpha-tocopheryl acetate (5 or 50 mg/kg BW), a mixture of lycopene and vitamin E (5 mg/kg BW each), or vehicle. Intraprostatic tumor volume and plasma PSA concentrations were measured at regular intervals. Mice were killed when the tumor load exceeded 1000 mm(3) or on d 95 when the study was terminated. Prostate and liver were analyzed by HPLC for lycopene isomers and alpha- and gamma, delta-tocopherol concentrations. None of the single treatments significantly reduced tumor volume. In contrast, combined treatment with lycopene and vitamin E, at 5 mg/kg BW each, suppressed orthotopic growth of PC-346C prostate tumors by 73% at d 42 (P < 0.05) and increased median survival time by 40% from 47 to 66 d (P = 0.02). The PSA index (PSA:tumor volume ratio) did not differ between experimental groups, indicating that PSA levels were not selectively affected. Lycopene was detected only in mice supplemented with lycopene. As in humans, most tissue lycopene was in the cis-isomer conformation, whereas 77% trans-lycopene was used in the dosing material. Liver alpha-tocopherol concentrations were increased in mice supplemented with both 50 mg/kg (226%, P < 0.05) and 5 mg/kg vitamin E (41%, P < 0.05), whereas prostate alpha-tocopherol concentrations were increased only by the higher dose (83%, P < 0.05). Our data provide evidence that lycopene combined with vitamin E may inhibit the growth of prostate cancer and that PSA can serve as a biomarker of tumor response for this treatment regimen.

Carotenoid actions and their relation to health and disease

Based on extensive epidemiological observation, fruits and vegetables that are a rich source of carotenoids are thought to provide health benefits by decreasing the risk of various diseases, particularly certain cancers and eye diseases. The carotenoids that have been most studied in this regard are beta-carotene, lycopene, lutein and zeaxanthin. In part, the beneficial effects of carotenoids are thought to be due to their role as antioxidants. beta-Carotene may have added benefits due its ability to be converted to vitamin A. Additionally, lutein and zeaxanthin may be protective in eye disease because they absorb damaging blue light that enters the eye. Food sources of these compounds include a variety of fruits and vegetables, although the primary sources of lycopene are tomato and tomato products. Additionally, egg yolk is a highly bioavailable source of lutein and zeaxanthin. These carotenoids are available in supplement form. However, intervention trials with large doses of beta-carotene found an adverse effect on the incidence of lung cancer in smokers and workers exposed to asbestos. Until the efficacy and safety of taking supplements containing these nutrients can be determined, current dietary recommendations of diets high in fruits and vegetables are advised.

Lycopene inhibits cell migration and invasion and upregulates Nm23-H1 in a highly invasive hepatocarcinoma, SK-Hep-1 cells

The carotenoid lycopene has been associated with decreased risks of several types of cancer, such as prostate cancer and hepatoma. Tumor metastasis is the most important cause of cancer death. Although lycopene was shown to inhibit metastasis, the mechanism underlying this action is not well understood. Here, we tested the possibility that lycopene may inhibit cancer cell metastasis by upregulating the expression of nm23-H1, a metastasis suppressor gene, in SK-Hep-1 cells, a highly invasive hepatoma cell line, and we determined migration and invasion activities and the expression of nm23-H1 protein and mRNA. We showed that lycopene inhibited SK-Hep-1 migration and invasion in a bell-shaped manner, with the highest effect at 5 micromol/L (91 and 63% inhibition for migration and invasion, respectively; P < 0.05). At the same test level (10 micromol/L), lycopene was much more effective than beta-carotene in reducing cell invasion (by approximately 870%). In contrast to the effects on migration and invasion, lycopene enhanced nm23-H1 expression at both the protein and mRNA levels; the effects were also bell shaped, and at 5 micromol/L, lycopene enhanced nm23-H1 protein and mRNA expressions by 220 +/- 33 and 153 +/- 22% (P < 0.01), respectively. These bell-shaped effects of lycopene may be related to autoxidation of lycopene at elevated concentrations (> or =10 micromol/L). Significant correlations existed between nm23-H1 protein expression and migration (r2= 0.78, P < 0.001) and between nm23-H1 protein expression and invasion (r2= 0.84, P < 0.001) in lycopene-treated SK-Hep-1 cells. We conclude that lycopene has significant antimigration and anti-invasion activity, and that this effect is associated with its induction of nm23-H1 expression.

The licorice root derived isoflavan glabridin increases the function of osteoblastic MC3T3-E1 cells

Glabridin, an isoflavan purified from licorice root, exhibits diverse biological activities, including estrogen-like activity. To investigate the bioactivities of glabridin, which act on bone metabolism, the effects of glabridin on the function of mouse osteoblastic cell line (MC3T3-E1) and the production of local factors in osteoblasts were studied. Glabridin (1-10microM) significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase (ALP) activity, collagen content and osteocalcin secretion in the cells (P<0.05). The effect of glabridin (10microM) in increasing ALP activity and collagen content was completely prevented by the presence of 10(-6)M cycloheximide and 10(-6)M tamoxifen, suggesting that glabridin's effect results from a newly synthesized protein component and might be partly involved in estrogen action. Then, the effects of glabridin on the TNF-alpha-induced apoptosis and production of prostaglandin E2 (PGE2) and nitric oxide (NO) in osteoblasts were examined. Treatment with glabridin (1-10microM) prevented apoptosis induced by TNF-alpha (10(-10)M) in osteoblastic cells. Moreover, glabridin (50microM) decreased the 10(-10)M TNF-alpha-induced production of PGE2 and NO in osteoblasts. Our data indicate that the enhancement of osteoblast function by glabridin may result in the prevention for osteoporosis and inflammatory bone diseases.

Combination of S-allylcysteine and lycopene induces apoptosis by modulating Bcl-2, Bax, Bim and caspases during experimental gastric carcinogenesis

Combination chemoprevention by diet-derived agents that induce apoptosis is a promising strategy to control gastric cancer, the second most common malignancy worldwide. The present study was undertaken to investigate the apoptosis-inducing potential of a combination of S-allylcysteine (SAC), an organosulphur constituent of garlic and lycopene, a tomato carotenoid during N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) and saturated sodium chloride (S-NaCl)-induced gastric carcinogenesis in Wistar rats using the apoptosis-associated proteins Bcl-2, Bax, Bim, caspase 8 and caspase 3 as markers. Animals administered MNNG followed by S-NaCl developed squamous cell carcinomas of the stomach associated with increased Bcl-2 expression and decreased expression of Bax, Bim, caspase 8 and caspase 3. Although SAC and lycopene alone significantly suppressed the development of gastric cancer, administration of SAC and lycopene in combination was more effective in inhibiting MNNG-induced stomach tumours and modulating the expression of apoptosis-associated proteins. Our results suggest that induction of apoptosis by SAC and lycopene combination represents one of the possible mechanisms that could account for their synergistic chemopreventive activity against gastric cancer.

Stereospecific high-performance liquid chromatographic analysis of naringenin in urine

A method of analysis of naringenin [(+/-)-4',5,7-trihydroxyflavanone] in biological fluids is necessary to study the kinetics of in vitro and in vivo metabolism, tissue distribution in fruits and humans. A simple high-performance liquid chromatographic method was developed for simultaneous determination of naringenin enantiomers in rat and human urine. Urine (0.1 ml) was precipitated with cold acetonitrile after addition of the internal standard, daidzein. Separation was achieved on a Chiralcel OD-RH column with UV detection at 292 nm. The calibration curves were linear ranging from 0.5 to 100 microg/ml for each enantiomer. The mean extraction efficiency was >99%. Precision of the assay was <9.4% (CV), and was within 5.4% at the limit of quantitation (0.5 microg/ml). Bias of the assay was lower than 16%, and was within 15% at the limit of quantitation. The assay was applied successfully to the urinary excretion of naringenin in rats and humans.

Attenuation of N-methyl-N'-nitro-N-nitrosoguanidine induced genotoxicity and oxidative stress by tomato and garlic combination

The protective effect of pretreatment with tomato and garlic against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced genotoxicity and oxidative stress was investigated in male Swiss mice. In vivo bone marrow micronucleus test was performed to assess the antigenotoxic effect of tomato and garlic. Oxidative stress was monitored by estimating the extent of lipid peroxidation and the status of the glutathione redox cycle antioxidants. Increased frequency of bone marrow micronuclei with enhanced lipid peroxidation was associated with compromised antioxidant defenses in MNNG treated animals. Although pretreatment with tomato and garlic significantly reduced the frequencies of MNNG-induced bone marrow micronuclei, the combination of tomato and garlic exerted a greater protective effect. This was associated with modulation of lipid peroxidation as well as reduced glutathione (GSH) and the GSH-dependent enzymes glutathione peroxidase (GPx) and glutathione-S-transferase (GST). These findings suggest that a diet containing even low levels of different naturally occurring compounds is effective in exerting antigenotoxic effects by modulating oxidative stress.

Terpenoids as Plant Antioxidants

Plant antioxidants are composed of a broad variety of different substances like ascorbic acid and tocopherols, polyphenolic compounds, or terpenoids. They perform several important functions in plants and humans (e.g., carotenoids function as accessory pigments for light harvesting and provide photoprotection and pigmentation in plants). Monoterpenes and diterpenes, which are the main components of essential oils, act as allelopathic agents, attractants in plant-plant or plant-pathogen/herbivore interactions or repellants. For humans, carotenoids play an important role for health, carotenoids with provitamin A activity are important for vision; other carotenoids influence the human immune function and gap-junctional communication (GJC). Additionally, their antioxidative capacity is believed to be responsible for the health promoting properties of fruits and vegetables. Three main ways of antioxidant action of carotenoids have been detected until now (i.e., quenching of singlet oxygen, hydrogen transfer, or electron transfer). These mechanisms and investigation of antioxidant activity in vitro are discussed in detail. The monoterpenes limonene and perillyl alcohol may be promising substances in cancer therapy. Several investigations have studied the antioxidant activity of monoterpenes and diterpenes or essential oils in vitro. Results as well as the action of a newly discovered, very effective antioxidant (i.e., gamma-terpinene) are discussed. An important point when assessing the antioxidant activity of plant antioxidants is to consider their interaction with other antioxidants. Especially combinations of hydrophilic and lipophilic antioxidants may exert synergistic effects, as has been shown for rutin in combination with gamma-terpinene, lutein, or lycopene.

Dietary antioxidants and paraoxonases against LDL oxidation and atherosclerosis development

Oxidative modification of low-density lipoprotein (LDL) in the arterial wall plays a key role in the pathogenesis of atherosclerosis. Under oxidative stress LDL is exposed to oxidative modifications by arterial wall cells including macrophages. Oxidative stress also induces cellular-lipid peroxidation, resulting in the formation of 'oxidized macrophages', which demonstrate increased capacity to oxidize LDL and increased uptake of oxidized LDL. Macrophage-mediated oxidation of LDL depends on the balance between pro-oxidants and antioxidants in the lipoprotein and in the cells. LDL is protected from oxidation by antioxidants, as well as by a second line of defense--paraoxonase 1 (PON1), which is a high-density lipoprotein-associated esterase that can hydrolyze and reduce lipid peroxides in lipoproteins and in arterial cells. Cellular paraoxonases (PON2 and PON3) may also play an important protective role against oxidative stress at the cellular level. Many epidemiological studies have indicated a protective role for a diet rich in fruits and vegetables against the development and progression of cardiovascular disease. A large number of studies provide data suggesting that consumption of dietary antioxidants is associated with reduced risk for cardiovascular diseases. Basic research provides plausible mechanisms by which dietary antioxidants might reduce the development of atherosclerosis. These mechanisms include inhibition of LDL oxidation, inhibition of cellular lipid peroxidation and consequently attenuation of cell-mediated oxidation of LDL. An additional possible mechanism is preservation/increment of paraoxonases activity by dietary antioxidants. This review chapter presents recent data on the anti-atherosclerotic effects and mechanism of action of three major groups of dietary antioxidants-vitamin E, carotenoids and polyphenolic flavonoids.

Lycopene enhances UVA–induced DNA damage and expression of heme oxygenase–1 in cultured mouse embryo fibroblasts

BACKGROUND

It has been suggested that carotenoids including lycopene may reduce the risk of photodamage. However, carotenoids are unstable under light exposure and may produce prooxidative effects under certain circumstances.

AIM OF THE STUDY

We examined whether lycopene inhibits ultraviolet A (UVA)-induced DNA damage and the expression of heme oxygenase-1 (HO-1). We hypothesized that the breakdown of lycopene by UVA irradiation, rather than intact lycopene itself, causes oxidative damage.

METHODS

Mouse fibroblasts, C3H10T1/2 (C3H), were first enriched with 10 microM of lycopene in the dark for 2 h before exposure to UVA (22.5 KJ/m2). Then, DNA damage measured by the single-cell gel electrophoretic assay (comet assay) and the expression of HO-1 measured by western blotting were determined. In addition, we exposed lycopene powder to UVA (22.5 KJ/m2) to prepare pre-irradiated lycopene (ILP). Then, C3H cells were incubated with ILP for 2 h, and DNA damage and the expression of HO-1 also were determined.

RESULTS

We found that lycopene enrichment did not cause damage to DNA in C3H cells not irradiated with UVA. However, lycopene enrichment strongly induced DNA damage when cells were irradiated with UVA (by ca. 2-fold as compared to control). In addition, lycopene enhanced UVA-induced HO-1 expression by ca. 2.5-fold. UVA irradiation led to a significant loss of lycopene that had been pre-incorporated into C3H cells. When cells were incubated with lycopene that had been pre-irradiated with UVA without subjecting the cells to further UVA irradiation, cellular DNA damage and expression of HO-1 were markedly increased, and these effects of irradiated lycopene were concentration-dependent.

CONCLUSIONS

These results demonstrate that lycopene enhances UVA-induced oxidative stress in C3H cells, and they suggest that under UVA irradiation, lycopene may produce oxidative products that are responsible for the prooxidant effects.

LDL Susceptibility to Copper-Induced Oxidation after Administration of a Single Dose of Free or Esterified Beta-Cryptoxanthin

BACKGROUND

The oxidative modification of LDL is believed to be an initial step in atherosclerosis. Thus, antioxidative substances such as carotenoids may have a role in the prevention of coronary heart disease. We examined the susceptibility of LDL to Cu2+ oxidation in young adults before and after a single dose of beta-cryptoxanthin.

METHODS

1.3 mg of beta-cryptoxanthin was administered to 12 apparently healthy young volunteers. Six of the volunteers received esters, the other six free beta-cryptoxanthin. The plasma concentration of beta-cryptoxanthin and the susceptibility of LDL to copper-induced oxidation ex vivo in terms of the duration of lag time were measured before and 12 h after beta-cryptoxanthin ingestion.

RESULTS

A single dose of beta-cryptoxanthin significantly increased the mean plasma beta-cryptoxanthin concentration and the mean cholesterol adjusted beta-cryptoxanthin concentration by 117 and 133%, respectively. No effect on the length of lag time was assessed. However, in LDL isolated from plasma 12 h after beta-cryptoxanthin administration the lengths of lag time correlated significantly with the plasma beta-cryptoxanthin concentration and with the cholesterol adjusted beta-cryptoxanthin levels. The lag time did not differ significantly between volunteers who received esters and those who received the same dosage as free beta-cryptoxanthin. At both measuring points, smokers, male volunteers and women using oral contraceptives tended to exhibit lower beta-cryptoxanthin concentrations and lower cholesterol adjusted beta-cryptoxanthin concentrations as well as increased LDL oxidizability compared to nonsmokers and women not using oral contraceptives.

CONCLUSION

A single dose of beta-cryptoxanthin does not enhance the duration of LDL lag time ex vivo in healthy young subjects.

The relationship between tomato intake and congestive heart failure risk in periodontitis subjects

BACKGROUND

The objective of this study was to investigate the relationship between monthly tomato consumption (MTC) and serum lycopene (sLyco) levels, and a self-reported history of congestive heart failure (CHF) in individuals with periodontitis using data available in the Third National Health and Nutrition Examination Survey (NHANES III).

METHODS

Adult participants in NHANES III were used in this study. Zero to thirty three percent of sites with a periodontal attachment loss (PAL) of >3 mm was considered a healthy periodontium, while greater than >33% of sites with PAL of >3 mm as periodontitis. The outcome variable was the self-reported history of CHF. MTC and sLyco levels were categorized into quartiles. Data was analyzed by Kruskal-Wallis, anova and multivariate analyses using SPSS(R). p<0.05 was used to reject the null hypothesis.

RESULTS

Individuals with periodontitis showed a dose-response relationship between dietary MTC and self-reported CHF risk; moderate MTC (risk ratio (RR), 3.15; 95% confidence interval (CI), 1.03-9.67), low MTC (RR, 3.31; 95% CI, 1.33-8.24) (p<0.05) and very low MTC (RR, 5.10; 95% CI, 1.67-15.57) (p<0.01), adjusting for confounders of both diseases (periodontitis and CHF). The moderate sLyco level-healthy periodontium group showed a significant decrease in CHF risk (RR, 0.25; 95% CI, 0.07-0.84) (p<0.05), adjusting for confounders. Significant inverse dose-response relationships were seen between sLyco and C-reactive protein, and MTC and white blood cell count in periodontitis subjects, respectively (p<0.05). MTC was correlated with sLyco concentration (r=-0.018, p<0.05), adjusting for confounders abolished that significance.

CONCLUSIONS

A relationship exists between periodontitis and CHF risk, and high MTC appears to affect this relationship in a positive direction in periodontitis subjects.

Orally administered rosmarinic acid is present as the conjugated and/or methylated forms in plasma, and is degraded and metabolized to conjugated forms of caffeic acid, ferulic acid and m-coumaric acid

Rosmarinic acid (RA) is contained in various Lamiaceae herbs used commonly as culinary herbs. Although RA has various potent physiological actions, little is known on its bioavailability. We therefore investigated the absorption and metabolism of orally administered RA in rats. After being deprived of food for 12 h, RA (50 mg/kg body weight) or deionized water was administered orally to rats. Blood samples were collected from a cannula inserted in the femoral artery before and at designated time intervals after administration of RA. Urine excreted within 0 to 8 h and 8 to 18 h post-administration was also collected. RA and its related metabolites in plasma and urine were measured by LC-MS after treatment with sulfatase and/or beta-glucuronidase. RA, mono-methylated RA (methyl-RA) and m-coumaric acid (COA) were detected in plasma, with peak concentrations being reached at 0.5, 1 and 8 h after RA administration, respectively. RA, methyl-RA, caffeic acid (CAA), ferulic acid (FA) and COA were detected in urine after RA administration. These components in plasma and urine were present predominantly as conjugated forms such as glucuronide or sulfate. The percentage of the original oral dose of RA excreted in the urine within 18 h of administration as free and conjugated forms was 0.44 +/- 0.21% for RA, 1.60 +/- 0.74% for methyl-RA, 1.06 +/- 0.35% for CAA, 1.70 +/- 0.45% for FA and 0.67 +/- 0.29% for COA. Approximately 83% of the total amount of these metabolites was excreted in the period 8 to 18 h after RA administration. These results suggest that RA was absorbed and metabolized as conjugated and/or methylated forms, and that the majority of RA absorbed was degraded into conjugated and/or methylated forms of CAA, FA and COA before being excreted gradually in the urine.

Supplementation of a diet low in carotenoids with tomato or carrot juice does not affect lipid peroxidation in plasma and feces of healthy men

Antioxidant properties of carotenoids are thought to be at least partly responsible for the protective effects of fruits and vegetables rich in carotenoids against colon cancer. There are large amounts of in vitro data supporting this hypothesis. But there is little known about the antioxidant effects of carotenoid-rich food in vivo particularly in the gastrointestinal tract. In a randomized, crossover trial, healthy men (n = 22) who were consuming a low-carotenoid diet drank 330 mL/d tomato juice or carrot juice for 2 wk. Antioxidant capacity was assessed by the "lag time" of ex vivo LDL oxidation induced by copper and lipid peroxidation as determined by measurements of malondialdehyde (MDA) in plasma and feces using HPLC with fluorescence detection. Although consumption of both carotenoid-rich juices for 2 wk increased the carotenoid level in plasma and feces (P < 0.001), the antioxidant capacity of LDL tended to be increased by only approximately 4.5% (P = 0.08), and lipid peroxidation in the men's plasma and feces was not affected. Thus, processes other than lipid peroxidation could be responsible for the preventive effects of tomatoes and carrots against colon cancer.

Lycopene in association with alpha-tocopherol or tomato lipophilic extracts enhances acyl-platelet-activating factor biosynthesis in endothelial cells during oxidative stress

Lipophilic compounds contained in tomato can prevent cardiovascular diseases by modulating the atherogenic processes in vascular endothelium mediated by oxidized low-density lipoproteins (LDLs). We investigated the effects of lycopene on the metabolism of platelet-activating factor (PAF) and its much less biologically active acyl analog, acyl-PAF, known to prevent LDL oxidation. Lycopene, or lycopene in association with alpha-tocopherol, or whole tomato lipophilic extracts (containing more than 80% lycopene) were used in experiments in which endothelial cells (ECs) are known to synthesize PAF following H(2)O(2)-induced oxidative stress. The results indicated that in each case H(2)O(2)-stimulated PAF biosynthesis in ECs, which is catalyzed by acetyl-CoA acetyltransferase (AT), appeared strongly inhibited. However, acyl-PAF biosynthesis, which also occurs through the PAF-dependent transacetylase (TA), was significantly increased by lycopene only when it was in association with alpha-tocopherol or with the minor compounds present in the whole lipophilic tomato extract. These findings suggest that alpha-tocopherol or lipophilic compounds present in tomato juice potentiate the effects of lycopene on the modulation of PAF and acyl-PAF biosynthesis in ECs during oxidative stress.

Preliminary evaluation of antinephritis and radical scavenging activities of glabridin from Glycyrrhiza glabra

Antinephritis activity of glabridin, a pyranoisoflavan isolated from Glycyrrhiza glabra, was evaluated after its oral administration to mice with glomerular disease (Masugi-nephritis) by measuring the urinary protein excretion, total cholesterol, serum creatinine and blood urea nitrogen levels. Administration of glabridin for 10 days (30 mg kg(-1) day(-1)) reduced the amount of urinary protein excretion from control level (100+/-23 mg/day) to a significantly lower level (47+/-4 mg/day). ESR spectroscopy demonstrated that glabridin neither produced radical, nor affected the radical intensity of sodium ascorbate, suggesting the lack of correlation between the antinephritis activity and radical scavenging activity.

Antioxidative properties of lycopene and other carotenoids from tomatoes: synergistic effects

Lycopene is the major carotenoid in tomatoes. Tomatoes contain a matrix of many bioactive components, including vitamin C, vitamin E, other carotenoids (a-, beta-, gamma- carotene, lutein), and flavonoids. Their synergistic interactions, when used in combination, may be responsible for the observed beneficial effects of tomato-based products. This study investigated the synergistic antioxidant activity of lycopene in combination with beta-carotene, vitamin E, and lutein. A liposome system was used to test the synergistic antioxidant activity. The carotenoid mixtures were more efficient in protecting liposome from oxidation than the individual carotenoid. Mixtures of lycopene and vitamin E appear to have the greatest synergistic antioxidant activity.

Depressive symptoms are independently correlated with lipid peroxidation in a female population: comparison with vitamins and carotenoids

OBJECTIVE

Lipid peroxidation (LPO) is involved in oxidative tissue injuries. The present investigation examined the association between LPO and psychological depressive symptoms.

METHODS

A cross-sectional study was conducted on 66 female volunteers aged 38-70. Lipid peroxides (LOOH) in serum were evaluated by hemoglobin-methylene blue (Hb-MB) method; additionally, serum antioxidants were also detected. To assess depressive symptoms, the Center for Epidemiologic Studies Depression (CES-D) Scale and a subscale in the 28-item General Health Questionnaire (GHQ) were applied.

RESULTS

LOOH concentration displayed a significant positive correlation with CES-D and GHQ depression scores. Multiple regression analysis was performed in which LOOH concentration served as a dependent variable and CES-D scores and antioxidants as independent variables. Consequently, CES-D scores demonstrated significant positive correlation with LOOH.

CONCLUSIONS

The positive relationship between depressive symptoms and LPO in a female population may support the hypothesis that LPO may affect depressive symptoms.

Protective Effects of Lycopene Against Ultraviolet B-Induced Photodamage

Lycopene, an acyclic hydrocarbon carotenoid found in tomatoes and their products, is a well-established potent antioxidant, and its anticancer properties have been shown in cultured cells and animal models. We investigated the protective effects of two concentrations of topical lycopene against acute ultraviolet B (UVB)-induced photodamage. Application of lycopene dose dependently inhibited UVB-induced ornithine decarboxylase (P < 0.05) and myeloperoxidase (P < 0.05) and significantly reduced bifold skin thickness (P < 0.05). Immunohistochemical staining revealed increased active caspase-3 of apoptotic pathway in the UVB-exposed group compared with the unexposed control. Application of topical lycopene prevented the cleavage of caspase-3. UVB irradiation completely diminished proliferating cell nuclear antigen (PCNA), and the untreated skin maintained positively stained cells throughout the basal epidermis. Topical application of lycopene significantly reversed UVB-induced PCNA inhibition, and normal PCNA staining was restored in the lycopene-treated skin. Our results suggest that topical lycopene is able to exert its protective effects against acute UVB-induced photodamage. Furthermore, it may act as a preventative agent via inhibition of epidermal ornithine decarboxylase activity, reducing inflammatory responses, maintaining normal cell proliferation, and possibly preventing DNA damage as indicated by blocking the necessitating step of apoptosis following UVB injury.

Complex Multivitamin Supplementation Improves Homocysteine and Resistance to LDL-C Oxidation

OBJECTIVE

We previously reported in an open-label pilot trial that a 24-ingredient multivitamin formula favorably influenced homocysteine concentration and LDL-C oxidation indices following 24 weeks of supplementation. Our current aim was to more thoroughly examine this same formula in a randomized, placebo-controlled, clinical study.

METHODS

We examined 182 participants for selected plasma vitamin concentrations and clinically relevant variables including homocysteine, lipids and LDL-C oxidation indices at baseline and six months.

RESULTS

We found no significant differences between groups for any parameter at baseline. Following six months of vitamin supplementation, we observed elevations in plasma concentrations of vitamin B6 (as pyridoxal 5'-phosphate; PLP), vitamin B12, folate, vitamin C, vitamin E and beta-carotene (p < 0.0001), all of which were significantly greater than respective placebo group changes (p < 0.0001). Homocysteine decreased in the treatment (8.38 +/- 2.9 vs. 6.93 +/- 2.5 micro mol/L; p < 0.0001) and placebo group (8.17 +/- 3.0 vs. 7.42 +/- 2.2 micro mol/L; p < 0.0001) from baseline to six months, respectively, with reductions in the treatment group being greater than placebo (p < 0.008). LDL-C oxidation indices were also improved as LDL-C oxidation rate was decreased (-0.39 micro mol/min/g protein; p < 0.0003) and LDL-C lag time increased (11.3 min; p < 0.003) in supplemented participants. Further analysis also showed that LDL-C oxidation rate was lower (p < 0.0007) and LDL-C lag time longer (p < 0.0001) for the vitamin group than placebo treatment after six months.

CONCLUSION

We conclude that a multi-ingredient vitamin formula with antioxidant properties has measurable effects on homocysteine and LDL-C oxidation indices.

The consumption of processed tomato products enhances plasma lycopene concentrations in association with a reduced lipoprotein sensitivity to oxidative damage

Lycopene, the predominant carotenoid in tomatoes, is hypothesized to mediate the health benefits of tomato products. We designed a study to examine the change in plasma lycopene and resistance of lipoproteins to ex vivo oxidative stress. Healthy individuals (n = 60; age >40 y; 30 men/30 women) consumed a lycopene-free diet for 1 wk and were subsequently randomized to receive 35 +/- 1, 23 +/- 1 or 25 +/- 1 mg lycopene/d from Campbell's Condensed Tomato Soup (CS), Campbell's Ready To Serve Tomato Soup (RTS) or V8 Vegetable Juice (V8), respectively, for 15 d. Total plasma lycopene concentrations decreased from 0.499 +/- 0.044 to 0.322 +/- 0.027 (35%, P < 0.0001) micro mol/L for the 60 participants during the 7-d washout period. After intervention, total lycopene concentrations increased for those consuming CS, RTS and V8 (compared with the washout period for each group) to 0.784 +/- 0.083 (123%, P < 0.0001), 0.545 +/- 0.061 (57%, P < 0.01) and 0.569 +/- 0.061 (112%, P < 0.0001) micro mol/L, respectively. The concentrations of all lycopene isomers decreased during the washout period. As a percentage of plasma total lycopene isomers for the 60 subjects, all-trans-lycopene decreased from 44.4 +/- 1.2 to 39.6 +/- 1.2 (P < 0.0001), whereas total cis-lycopene isomers increased from 55.6 +/- 1.2 to 60.4 +/- 1.2 (P < 0.0001) during the washout period, a shift that was reversed by consumption of tomato products for 15 d. The ex vivo lipoprotein oxidation lag period, used as a measure of antioxidant capacity, increased significantly from 64.7 +/- 2.4 min at the end of the washout period (all groups) to 70.1 +/- 4.0 (P < 0.05), 68.3 +/- 2.4 (P < 0.05) and 71.7 +/- 4.0 min (P < 0.01) after treatment for the CS, RTS and V8 groups, respectively. This study shows that lycopene concentrations and isomer patterns change rapidly with variation in dietary intake. In addition, 15 d of tomato product consumption significantly enhanced the protection of lipoproteins to ex vivo oxidative stress.

Naringenin from cooked tomato paste is bioavailable in men

Naringenin has been shown to exert antiestrogenic, cholesterol-lowering and antioxidant activities, as well as an indirect modulation on the metabolism of many xenobiotics. It is one of the most abundant polyphenols in tomato. Given the widespread consumption of tomato (Lycopersicum esculentum) and tomato-based products, this study was designed to determine whether plasma levels of naringenin were detectable in five men after consumption of a test meal containing 150 mg of cooked tomato paste. Naringenin intake with the test meal was 3.8 mg. Blood was drawn from fasting subjects and 2, 4, 6, 8 and 24 h after the meal. To compare the results with a control, the same meal without tomato paste (control meal) was administered to the same subjects 2 wk later. Analyses were performed using high-performance liquid chromatography coupled with a CoulArray electrochemical detector. The peak plasma concentration was 0.12 +/- 0.03 micro mol/L 2 h after the meal. Unconjugated naringenin was not detected. Naringenin was not detected in plasma at any time after consumption of the control meal. In addition to naringenin, we detected rutin and chlorogenic acid in tomato paste, but these polyphenols and their derivatives (quercetin and caffeic acid) were not detected in plasma at any time. To the best of our knowledge, this is the first study demonstrating naringenin bioavailability in humans after consumption of a meal containing cooked tomato paste.

Nonenzymatic antioxidant activity of four organosulfur compounds derived from garlic

The nonenzymatic antioxidant activity of diallyl sulfide (DAS), diallyl disulfide (DADS), S-ethyl cysteine (SEC), and N-acetyl cysteine (NAC) in the liposome system was examined. The antioxidant protection from these organosulfur agents was concentration dependent (p < 0.05). SEC and NAC showed significantly lower lipophilicity and greater reducing power than DAS and DADS (p < 0.05). Greater antioxidant protection was presented in the combinations of alpha-tocopherol with four organosulfur agents than alpha-tocopherol treatment alone (p < 0.05), and SEC and NAC showed greater sparing effects on alpha-tocopherol (p < 0.05). Four organosulfur agents lost antioxidant activity when the temperature was 65 degrees C (p < 0.05). At pH 2.5 and 10, DAS and DADS still showed antioxidant activity (p < 0.05). On the basis of the observed nonenzymatic antioxidant protection, these organosulfur compounds are potent agents for enhancing lipid stability.

Increased macrophage glutathione content reduces cell-mediated oxidation of LDL and atherosclerosis in apolipoprotein E-deficient mice

We used the apolipoprotein E deficient (apo e-/-) mice to analyze the role of macrophage reduced glutathione (GSH) content in cell-mediated oxidation of LDL and in atherosclerotic lesion development. Apo e-/- mice were supplemented with L-2-oxo-4-thiazolidin carboxylate (OTC, which supplies cysteine residues, 500 mg/kg/day), or with buthionine sulfoximine (BSO, a specific inhibitor of GSH synthesis, 400 mg/kg/day) for 6 weeks. Then mouse peritoneal macrophages (MPM) and the mice aortas were collected. MPM from apo e-/- mice contained decreased GSH levels (by 58%), and a four-fold increased lipid peroxides content compared to control macrophages from C57BL6 mice. These MPM demonstrated increased capability to release superoxide anions and to oxidize LDL in comparison to control MPM. OTC supplementation resulted in a 26% increase in macrophage GSH, paralleled by a 25% reduction in cellular lipid peroxides content. Decrement by 30% in superoxide anion release and LDL oxidation by MPM, and also in the atherosclerotic lesion size by 25%, was found in the OTC-treated mice, compared to placebo-treated apo e-/- mice. In contrast, in BSO-treated mice MPM a further depletion of cellular GSH by 22% was found, paralleled by a two-fold increase in lipid peroxides content, and a 41% increased superoxide anion release and cell-mediated LDL oxidation, compared to placebo-treated apo e-/- mice MPM. Most important, BSO supplementation to apo e-/- mice caused a 59% increase in the atherosclerotic lesion area. An additional way to increase cellular GSH content was the use of dietary antioxidants. Vitamin E (40 mg/kg/day) or the isoflavan glabridin (25 microg/kg/day) administration for 2 months to apo e-/- mice resulted in the accumulation of these antioxidants in their MPM, and increased MPM GSH content by 24 and 80%, respectively. MPM lipid peroxides content was reduced by 31 or 60% upon vitamin E or glabridin supplementation, paralleled by a 30 or 60% decrease in cell-mediated oxidation of LDL, respectively. Finally, a significant inverse correlation (R=0.83) was found between macrophage GSH content and cell-mediated oxidation of LDL. We conclude that enrichment in vivo of macrophages with GSH, significantly decreases cellular oxidative stress, leading to reduced capability of the macrophages to oxidize LDL, and hence GSH may attenuate the development of atherosclerosis.

CYP98A6 from Lithospermum erythrorhizon encodes 4-coumaroyl-4'-hydroxyphenyllactic acid 3-hydroxylase involved in rosmarinic acid biosynthesis

Rosmarinic acid is the dominant hydroxycinnamic acid ester accumulated in Boraginaceae and Lamiaceae plants. A cytochrome P450 cDNA was isolated by differential display from cultured cells of Lithospermum erythrorhizon, and the gene product was designated CYP98A6 based on the deduced amino acid sequence. After expression in yeast, the P450 was shown to catalyze the 3-hydroxylation of 4-coumaroyl-4'-hydroxyphenyllactic acid, one of the final two steps leading to rosmarinic acid. The expression level of CYP98A6 is dramatically increased by addition of yeast extract or methyl jasmonate to L. erythrorhizon cells, and its expression pattern reflected the elicitor-induced change in rosmarinic acid production, indicating that CYP98A6 plays an important role in regulation of rosmarinic acid biosynthesis.

Synthesis of 2-O-(4-coumaroyl)-3-(4-hydroxyphenyl)lactic acid, an important intermediate of rosmarinic acid biosynthesis

A simple method to synthesize (+/-)-2-O-(4-coumaroyl)-3-(4-hydroxyphenyl)lactic acid (1), a key intermediate in rosmarinic acid biosynthesis in higher plant cells, was established by condensation of protected 4-coumaric acid and (+/-)-3-(4-hydroxyphenyl)lactic acid followed by deprotection. A stable supply of 1 thus attained will lead to biochemical and molecular biological characterization of later steps of rosmarinic acid biosynthesis.

Flavonoids protect LDL from oxidation and attenuate atherosclerosis

Consumption of some plant-derived flavonoids results in their absorption and appearance in plasma and tissues. The inverse relationship between dietary flavonoids consumption and cardiovascular diseases may be associated with the ability of flavonoids to attenuate LDL oxidation, macrophage foam cell formation and atherosclerosis. The effect of flavonoids on arterial cell-mediated oxidation of LDL is determined by their accumulation in the lipoprotein and in arterial cells, such as macrophages. Flavonoids can reduce LDL lipid peroxidation by scavenging reactive oxygen/nitrogen species, chelation of transition metal ions and sparing of LDL-associated antioxidants. They can also reduce macrophage oxidative stress by inhibition of cellular oxygenases [such as nicotinamide adenine dinucleotide phosphate, reduced form (NADPH) oxidase] or by activating cellular antioxidants (such as the glutathione system). Thus, plant flavonoids, as potent natural antioxidants that protect against lipid peroxidation in arterial cells and lipoproteins, significantly attenuate the development of atherosclerosis.