Lycopene, β-carotene, and colorectal adenomas

Food Intake and Colorectal Cancer

Colorectal cancer (CRC) accounts for considerable mortalities worldwide. Several modifiable risk factors, including a high intake of certain foods and beverages can cause CRC. This review summarized the latest findings on the intake of various foods, nutrients, ingredients, and beverages on CRC development, with the objective of classifying them as a risk or protective factor. High-risk food items include red meat, processed meat, eggs, high alcohol consumption, sugar-sweetened beverages, and chocolate candy. Food items that are protective include milk, cheese and other dairy products, fruits, vegetables (particularly cruciferous), whole grains, legumes (particularly soy beans), fish, tea (particularly green tea), coffee (particularly among Asians), chocolate, and moderate alcohol consumption (particularly wine). High-risk nutrients/ingredients include dietary fat from animal sources and industrial trans-fatty acids (semisolid/solid hydrogenated oils), synthetic food coloring, monosodium glutamate, titanium dioxide, and high-fructose corn sirup. Nutrients/ingredients that are protective include dietary fiber (particularly from cereals), fatty acids (medium-chain and odd-chain saturated fatty acids and highly unsaturated fatty acids, including omega-3 polyunsaturated fatty acids), calcium, polyphenols, curcumin, selenium, zinc, magnesium, and vitamins A, C, D, E, and B (particularly B6, B9, and B2). A combination of micronutrients and multi-vitamins also appears to be beneficial in reducing recurrent adenoma incidence.

Effect Modification of Selenium Supplementation by Intake and Serum Concentrations of Antioxidants on the Development of Metachronous Colorectal Adenoma

BACKGROUND

Selenium (Se) is a trace element that has been investigated as a potential chemopreventive agent for colorectal cancer. Dietary intake of other antioxidant nutrients may modify the effect of Se.

OBJECTIVE

We examined the association between intake and serum concentrations of retinol, β-carotene, β-cryptoxanthin, lycopene, lutein/zeaxanthin, and α- and γ-tocopherol and the development of metachronous colorectal adenoma, and if these nutrients modified the effect of Se.

METHODS

We conducted a prospective study of 1874 participants from the Se Trial with data for antioxidant intake, as well as a subcohort of 508 participants with serum biomarker concentrations.

RESULTS

Statistically significantly lower odds for the development of metachronous adenoma were observed for those participants in the highest tertile of intake for lutein/zeaxanthin compared to the lowest, with an OR (95% CI) of 0.72 (0.56-0.94). No effect modification for intake of any nutrient was observed. However, circulating concentrations of lycopene exhibited statistically significant effect modification of selenium supplementation (p < 0.06).

CONCLUSION

These findings show that intake and circulating concentrations of antioxidant nutrients were not consistently associated with reduced odds for the development of metachronous lesions, although blood concentrations of lycopene may modify the effect of selenium supplementation.

Xanthophylls from the Sea: Algae as Source of Bioactive Carotenoids

Algae are considered pigment-producing organisms. The function of these compounds in algae is to carry out photosynthesis. They have a great variety of pigments, which can be classified into three large groups: chlorophylls, carotenoids, and phycobilins. Within the carotenoids are xanthophylls. Xanthophylls (fucoxanthin, astaxanthin, lutein, zeaxanthin, and β-cryptoxanthin) are a type of carotenoids with anti-tumor and anti-inflammatory activities, due to their chemical structure rich in double bonds that provides them with antioxidant properties. In this context, xanthophylls can protect other molecules from oxidative stress by turning off singlet oxygen damage through various mechanisms. Based on clinical studies, this review shows the available information concerning the bioactivity and biological effects of the main xanthophylls present in algae. In addition, the algae with the highest production rate of the different compounds of interest were studied. It was observed that fucoxanthin is obtained mainly from the brown seaweeds Laminaria japonica, Undaria pinnatifida, Hizikia fusiformis, Sargassum spp., and Fucus spp. The main sources of astaxanthin are the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp. Lutein and zeaxanthin are mainly found in algal species such as Scenedesmus spp., Chlorella spp., Rhodophyta spp., or Spirulina spp. However, the extraction and purification processes of xanthophylls from algae need to be standardized to facilitate their commercialization. Finally, we assessed factors that determine the bioavailability and bioaccesibility of these molecules. We also suggested techniques that increase xanthophyll’s bioavailability.

Green synthesis of silver, iron and gold nanoparticles of lycopene extracted from tomato: their characterization and cytotoxicity against COLO320DM, HT29 and Hella cell

Our study aimed at development of Silver, Iron and Gold nanoparticles of Lycopene isolated from tomato by using green synthesis technique and to evaluate its anticancer potential against colorectal and cervical cancer. Lycopene was extracted by benzene extraction method and the silver, iron and gold nanoparticles were developed by green synthesis method. 1% aqueous extract of isolated Lycopene was mixed with 1% solutions of AgNO₃, FeCl₃ and HAuCl₄ solutions and incubated at ambient temperature for 3-4 h separately and observed for the color change which is an indicative of formation of the nanoparticles. The prepared nanoparticles were characterized by FTIR, SEM, XRD analysis and evaluated for their antimicrobial potential. The cytotoxicity studies were carried out by in vitro assay like MTT, SRB and Tryphan blue method against Colo 320 DM, HT 29, and Hella. SEM showed nanosized particles of 50-100 nm range, whereas no antimicrobial activity was exhibited by the prepared nanoparticles. In MTT assay the LyAgNP showed maximum 41.41 ± 0.4124% inhibition against COLO320DM, whereas LyGNP exhibited 41.47 ± 0.4469% inhibition against HT 29 and LyAgNP showed 40.9 ± 0.6908% inhibition against Hella cells. In SRB assay LyAgNP showed maximum 82.68 ± 1.1798% inhibition against COLO320DM, whereas LyGNP exhibited maximum 91.21 ± 0.2372% inhibition against HT29 and 87.98 ± 0.5878% inhibition against Hella cells. In tryphan blue assay against COLO320DM, HT29 and Hella cells, the maximum inhibition exhibited by the prepared nanoparticles were observed as LyGNP 83.45 ± 0.4694%, LyAgNP 88.05 ± 0.1870% and LyAgNP65.47 ± 0.4766%. We conclude that the developed nanoparticles of Lycopene exhibited potential anticancer activity against Colorectal and cervical cancer cell as compared with pure Lycopene.

Comparative Analysis of Lycopene Content from Different Tomato-Based Food Products on the Cellular Activity of Prostate Cancer Cell Lines

Lycopene is more bioavailable in processed tomato products than in raw tomatoes, since arrangement of cis-isomers of lycopene during food processing and storage may increase its biological activity. The aim of the study is evaluate the influence of lycopene content from different tomato-based food products (extract, paste, ketchup and sauce) on cell proliferation, cell cycle, and rate of apoptosis of human prostate cancer cell lines. DU-145 and PC-3 cell lines were treated with lycopene content from different tomato-based food products (500-5000 μg/mL) for 96 h. The data showed a decrease in cell viability in both DU-145 and PC-3 cells after treatment with all lycopene extracts from tomato-based food products. Analysis of cell cycle revealed a decrease in the percentage of prostate cancer cells in G0/G1 and G2/M phases after 96 h of treatment when using lycopene content from tomato paste and tomato extract. However, lycopene extracted from tomato sauce and ketchup promoted a decrease in the percentage of cells in G0/G1 phase and an increase in S and G2/M phases after 96 h of treatment. Lycopene content from all of those tomato-based food products also increased apoptosis in both prostate cancer cell lines. In this regard, lycopene has proved to be a potent inhibitor of cell viability, arrest cell cycle and increase the apoptosis in human prostate cancer cells, suggesting an effect in the balance of human prostate cancer cell lines growth.

Lycopene, sulforaphane, quercetin, and curcumin applied together show improved antiproliferative potential in colon cancer cells in vitro

Lycopene, sulforaphane, quercetin, and curcumin, ingredients of daily diet, show significant anticancer and chemopreventive potential; however, no data are available showing thorough evaluation of jointly used phytochemicals on cancer cell proliferation. Here, we compare anticancer potential of mentioned substances applied separately or in combination (as MIX) by measuring mitochondrial activity (MTT test), DNA synthesis (BrdU test) and lactate dehydrogenase release (LDH test) in colon epithelial (CCD841 CoTr), and colon cancer (HT-29, LS174T) cells. Additive inhibitory effect of simultaneously used phytochemicals on cancer cells proliferation has been shown. In epithelial cells, tested combination effectively inhibited mitochondrial activity, but not DNA synthesis. LDH test revealed cytotoxicity of tested mixture against cancer cells without negative effect on normal cells. Furthermore, we demonstrated that MIX enhances antiproliferative effect of common cytostatics: 5-fluorouracil and cisplatin. Presented data suggest chemopreventive potential of the proposed combination of natural substances and their usefulness as adjuvant strategy during chemotherapy. PRACTICAL APPLICATIONS: Colorectal cancer is one of the most common causes of cancer death worldwide. Since its development and progression is strongly correlated with dietary habits, healthy diet as well as supplementation with proved anticancer agents seems to be reasonable strategy of colon cancer prevention and treatment. In the present study, we have focused on four natural compounds abundantly found in daily diet i.e., lycopene, sulforaphane, quercetin, and curcumin, with well established anticancer potential. Their individual and collective impact both on normal colon epithelium cells and colon cancer cells viability, growth, and proliferation was examined. Furthermore, activity of the substances combined as MIX to influence antiproliferative potential of commonly used in colon cancer treatment cytostatics, 5-fluorouracil, and cisplatin was verified. Proposed in the study combination of phytochemicals with experimentally proven antiproliferative activity may propose an effective strategy for prevention and treatment of colon cancer.

Comparative analysis of different dietary antioxidants on oxidative stress pathway genes in L6 myotubes under oxidative stress

Enhanced oxidative stress plays an important role in the progression and onset of diabetes and its complications. Strategies or efforts meant to reduce the oxidative stress are needed which may mitigate these pathogenic processes. The present study aims to investigate the in vitro ameliorative potential of nine antioxidant molecules in L6 myotubes under oxidative stress condition induced by 4-hydroxy-2-nonenal and also to comprehend the gene expression patterns of oxidative stress genes upon the supplementation of different antioxidants in induced stress condition. The study results demonstrated a marked increase in the level of malondialdehyde and protein carbonyl content with a subsequent increase in the free radicals that was reversed by the pretreatment of different dietary antioxidant. From the expression analysis of the oxidative stress genes, it is evident that the expression of these genes is modulated by the presence of antioxidants. The highest expression was found in the cells treated with Insulin in conjugation with an antioxidant. Resveratrol is the most potent modulator followed by Mangiferin, Estragole, and Capsaicin. This comparative analysis ascertains the potency of Resveratrol along with Insulin in scavenging the reactive oxygen species (ROS) generated under induced stress conditions through antioxidant defense mechanism against excessive ROS production, contributing to the prevention of oxidative damage in L6 myotubes.

A Review of the Biological Activities of Microalgal Carotenoids and Their Potential Use in Healthcare and Cosmetic Industries

Carotenoids are natural pigments that play pivotal roles in many physiological functions. The characteristics of carotenoids, their effects on health, and the cosmetic benefits of their usage have been under investigation for a long time; however, most reviews on this subject focus on carotenoids obtained from several microalgae, vegetables, fruits, and higher plants. Recently, microalgae have received much attention due to their abilities in producing novel bioactive metabolites, including a wide range of different carotenoids that can provide for health and cosmetic benefits. The main objectives of this review are to provide an updated view of recent work on the health and cosmetic benefits associated with carotenoid use, as well as to provide a list of microalgae that produce different types of carotenoids. This review could provide new insights to researchers on the potential role of carotenoids in improving human health.

Pharmacological Intervention through Dietary Nutraceuticals in Gastrointestinal Neoplasia

Neoplastic conditions associated with gastrointestinal (GI) tract are common worldwide with colorectal cancer alone accounting for the third leading rate of cancer incidence. Other GI malignancies such as esophageal carcinoma have shown an increasing trend in the last few years. The poor survival statistics of these fatal cancer diseases highlight the need for multiple alternative treatment options along with effective prophylactic strategies. Worldwide geographical variation in cancer incidence indicates a correlation between dietary habits and cancer risk. Epidemiological studies have suggested that populations with high intake of certain dietary agents in their regular meals have lower cancer rates. Thus, an impressive embodiment of evidence supports the concept that dietary factors are key modulators of cancer including those of GI origin. Preclinical studies on animal models of carcinogenesis have reflected the pharmacological significance of certain dietary agents called as nutraceuticals in the chemoprevention of GI neoplasia. These include stilbenes (from red grapes and red wine), isoflavones (from soy), carotenoids (from tomatoes), curcuminoids (from spice turmeric), catechins (from green tea), and various other small plant metabolites (from fruits, vegetables, and cereals). Pleiotropic action mechanisms have been reported for these diet-derived chemopreventive agents to retard, block, or reverse carcinogenesis. This review presents a prophylactic approach to primary prevention of GI cancers by highlighting the translational potential of plant-derived nutraceuticals from epidemiological, laboratory, and clinical studies, for the better management of these cancers through consumption of nutraceutical rich diets and their intervention in cancer therapeutics.

Furan toxicity on testes and protective role of lycopene in diabetic rats

OBJECTIVE

Furan (C₄H₄O) is a heat-induced food contaminant that is utilized as an industrial chemical agent. Lycopene is a natural substance that is produced by plants and tomatoes. We aimed to evaluate the toxicity of furan on testes and the protective effect of lycopene in diabetic rats.

MATERIAL AND METHODS

Male Wistar albino rats were divided into five groups: Group 1 (control group) received 1 mL/kg corn oil. Group 2 (diabetic control group) received 55 mg/kg STZ and 1 mL/kg corn oil. Group 3 (diabetic lycopene group) received 55 mg/kg STZ and 4 mg/kg lycopene. Group 4 (diabetic furan group) received 55 mg/kg STZ and 40 mg/kg furan. Group 5 (diabetic furan + lycopene group) received 55 mg/kg STZ, 40 mg/kg furan, and 4 mg/kg lycopene. After 28 days, the testes were extirpated in all groups. In the testicular tissue samples, the level of malondialdehyde (MDA) and the activities of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), and reducted glutathione (GST) were studied. Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were measured. Histopathologic examination was performed by light microscope.

RESULTS

The MDA level and the activities of CAT, GPx, SOD, and GST were found to be higher in the furan group than in the control and diabetic control groups (p<0.05). The MDA level and the activities of CAT, GPx, SOD, and GST were significantly lower in the furan + lycopene group than in the furan group (p<0.05).

CONCLUSION

The low blood testosterone level in the rats who received furan suggested the presence of endocrinological defects and cellular degenerative changes. Lycopene may be effective to reverse furan toxicity in diabetic rat testes.

Inhibition of colon cancer cell growth by nanoemulsion carrying gold nanoparticles and lycopene

Lycopene (LP), an important functional compound in tomatoes, and gold nanoparticles (AN), have received considerable attention as potential candidates for cancer therapy. However, the extreme instability and poor bioavailability of LP limits its in vivo application. This study intends to develop a nanoemulsion system incorporating both LP and AN, and to study the possible synergistic effects on the inhibition of the HT-29 colon cancer cell line. LP-nanogold nanoemulsion containing Tween 80 as an emulsifier was prepared, followed by characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS) analysis, ultraviolet spectroscopy, and zeta potential analysis. The particle size as determined by TEM and DLS was 21.3±3.7 nm and 25.0±4.2 nm for nanoemulsion and 4.7±1.1 nm and 3.3±0.6 nm for AN, while the zeta potential of nanoemulsion and AN was -32.2±1.8 mV and -48.5±2.7 mV, respectively. Compared with the control treatment, both the combo (AN 10 ppm plus LP 12 μM) and nanoemulsion (AN 0.16 ppm plus LP 0.4 μM) treatments resulted in a five- and 15-fold rise in early apoptotic cells of HT-29, respectively. Also, the nanoemulsion significantly reduced the expressions of procaspases 8, 3, and 9, as well as PARP-1 and Bcl-2, while Bax expression was enhanced. A fivefold decline in the migration capability of HT-29 cells was observed for this nanoemulsion when compared to control, with the invasion-associated markers being significantly reversed through the upregulation of the epithelial marker E-cadherin and downregulation of Akt, nuclear factor kappa B, pro-matrix metalloproteinase (MMP)-2, and active MMP-9 expressions. The TEM images revealed that numerous nanoemulsion-filled vacuoles invaded cytosol and converged into the mitochondria, resulting in an abnormally elongated morphology with reduced cristae and matrix contents, demonstrating a possible passive targeting effect. The nanoemulsion containing vacuoles were engulfed and internalized by the nuclear membrane envelop for subsequent invasion into the nucleoli. Taken together, LP-nanogold nanoemulsion could provide synergistic effects at AN and LP doses 250 and 120 times lower than that in the combo treatment, respectively, demonstrating the potential of nanoemulsion developed in this study for a possible application in colon cancer therapy.

Free radicals, natural antioxidants, and their reaction mechanisms

The normal biochemical reactions in our body, increased exposure to the environment, and higher levels of dietary xenobiotic's result in the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS).

The electrophoretical determination of serum protein fractions in lycopene treated experimental diabetic rats

This study was planned to determine the effects of lycopene treatment on serum protein fractions in experimental diabetic rats. In order to induce diabetes in rats in the diabetes (D) and diabetes + lycopene (DL) groups, rats were given 45 mg/kg single-dose streptozotocin intraperitoneally. Lycopene (10 mg/kg/day dissolved in sunflower oil) was administered to the rats in the lycopene-only (L) and DL groups. Blood glucose levels and HbA1c% in DL group and diabetes group increased (p < 0.05) compared to control and L group. Total protein, albumin, α1, α2, and β globulin fractions of diabetic and DL groups were lower than control and L groups (p < 0.05). D group had lowest gamma (γ) globulin levels among other groups (p < 0.05). The γ globulin levels was slightly increased than diabetic groups (D and DL), but it was still lower than control and L groups (p < 0.05). The highest value of A/G ratio was observed in diabetic group. Similarly, the % level of A/G ratio of D group was higher than other groups. It was noted that the A/G ratio decreased and reached to control group levels after lycopene treatment.

Carotenoid intake and risk of colorectal adenomas in a cohort of male health professionals

PURPOSE

Carotenoids have been hypothesized to prevent carcinogenesis through their antioxidant and pro-vitamin A properties. We examined associations between intakes of specific carotenoids and risk of colorectal adenomas.

METHODS

Among 29,363 men who reported having a lower bowel endoscopy between 1986 and 2006, 3,997 cases of colorectal adenoma were identified in the Health Professionals Follow-up Study. Participants completed food frequency questionnaires every 4 years; dietary information was cumulatively updated. The associations between carotenoid intakes and risk of colorectal adenomas overall and by anatomic site, stage, smoking status and alcohol consumption were investigated using multivariate logistic regression models.

RESULTS

Total β-carotene and dietary β-carotene, lycopene and lutein/zeaxanthin intakes and the total carotenoid score were inversely associated with colorectal adenoma risk. The odds ratios (95 % confidence intervals) comparing the highest versus lowest quintile of intake were 0.78 (0.69-0.88) for total β-carotene, 0.72 (0.64-0.81) for dietary β-carotene, 0.83 (0.74-0.93) for lycopene, 0.86 (0.76-0.96) for lutein/zeaxanthin, and 0.87 (0.77-0.97) for the total carotenoid score. Associations for α-carotene and β-cryptoxanthin intakes were null. We did not find significant differences in the associations between intakes of each carotenoid and risk of colorectal adenoma by anatomic site or stage (all p values, test for common effects >0.10). The inverse associations we observed for total β-carotene and dietary β-carotene, lycopene, and lutein/zeaxanthin intakes and the total carotenoid score with adenoma risk also did not vary by smoking status and alcohol consumption.

CONCLUSION

This study found that a diet high in carotenoids was associated with a reduced risk of colorectal adenomas.

Concomitant consumption of lycopene and fish oil inhibits tumor growth and progression in a mouse xenograft model of colon cancer

SCOPE

Our previous report showed that concomitant supplementation of lycopene and eicosa-pentaenoic acid synergistically inhibited the proliferation of human colon cancer HT-29 cells in vitro.

METHODS AND RESULTS

To validate our findings, the present study investigated whether consumption of lycopene and fish oil would help prevent tumor growth and progression in a mouse xenograft model of colon cancer. The inhibitory effects of lycopene and fish oil on tumor growth were verified by western blotting analysis, bioluminescent imaging, immunohistochemical (IHC) staining and ELISA. The results demonstrated that lycopene and fish oil synergistically inhibited the growth of colon cancer in tumor-bearing mice. The bioluminescent imaging, histopathological and IHC staining results indicated that lycopene and fish oil effectively suppressed tumor growth and progression of colon cancer in vivo. The chemopreventive effects of lycopene and fish oil were associated with augmented expression of the cell cycle inhibitors such as p21(CIP1/WAF1) and p27(Kip1) , and suppression of proliferating cell nuclear antigen, β-catenin, cyclin D1 and c-Myc proteins. Furthermore, lycopene and fish oil inhibited tumor progression through suppression of MMP-7, MMP-9, COX-2 and PGE2.

CONCLUSION

These results show that lycopene and fish oil act synergistically as chemopreventive agents against tumor growth and progression in a mouse xenograft model of colon cancer.

Effect of lycopene on cell viability and cell cycle progression in human cancer cell lines

BACKGROUND

Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound's action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines.

METHODS

Human cell lines were treated with lycopene (1-5 μM) for 48 and 96 h. Cell viability was monitored using the method of MTT. The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling (TUNEL) and by DAPI.

RESULTS

Our data showed a significant decrease in the number of viable cells in three cancer cells lines (HT-29, T84 and MCF-7) after 48 h treatment with lycopene, and changes in the fraction of cells retained in different cell cycle phases. Lycopene promoted also cell cycle arrest followed by decreased cell viability in majority of cell lines after 96 h, as compared to controls. Furthermore, an increase in apoptosis was observed in four cell lines (T-84, HT-29, MCF-7 and DU145) when cells were treated with lycopene.

CONCLUSIONS

Our findings show the capacity of lycopene to inhibit cell proliferation, arrest cell cycle in different phases and increase apoptosis, mainly in breast, colon and prostate lines after 96 h. These observations suggest that lycopene may alter cell cycle regulatory proteins depending on the type of cancer and the dose of lycopene administration. Taken together, these data indicated that the antiproliferative effect of lycopene was cellular type, time and dose-dependent.

Nutrition, intestinal permeability, and blood ethanol levels are altered in patients with nonalcoholic fatty liver disease (NAFLD)

BACKGROUND

A role of an altered dietary pattern (e.g., a diet rich in sugar) but also alterations at the level of the intestinal barrier have repeatedly been discussed to be involved in the development and progression of nonalcoholic fatty liver disease (NAFLD).

AIMS

To determine if the nutritional intake, intestinal flora, and permeability and the development of NAFLD are related in humans.

METHODS

Ten controls and 20 patients with NAFLD ranging from simple steatosis to steatohepatitis were included in the study. Bacterial overgrowth, orocecal transit time, and intestinal permeability were assessed. Alcohol, endotoxin, and plasminogen activator inhibitor (PAI-) 1 concentration were determined in plasma. Nutritional intake was assessed using a dietary history.

RESULTS

Despite no differences in the prevalence of bacterial overgrowth and in the orocecal transit time, intestinal permeability, alcohol, and endotoxin levels in plasma were significantly higher in patients with NAFLD than in controls. Similar results were also found for PAI-1 plasma concentrations. Patients with NAFLD had a significantly higher intake of protein, total carbohydrates, and mono- as well as disaccharides than controls. PAI-1, endotoxin, and ALT plasma levels were positively related to total protein and carbohydrate intake.

CONCLUSIONS

Taken together, our results indicate that intestinal permeability, endogenous alcohol synthesis, and nutritional intake are markedly altered in patients with NAFLD.

The effect of lycopene treatment on ACE activity in rats with experimental diabetes

In this study, the anti-inflammatory and antioxidant known as lycopene was applied to rats with experimental diabetes with the aim of investigating the detection of diabetes-related complications, and to determine the possible role of lycopene in diabetes complications regarding the effects of ACE activity. In order to induce diabetes in rats in the diabetes (D) and diabetes+lycopene (DL) groups, rats were given 45 mg/kg single-dose streptozotocin (STZ) intraperitoneally (i.p.); lycopene (10 mg/kg/day dissolved in sunflower oil) was administered to the rats in the lycopene-only (L) and DL groups. Blood glucose levels and HbA1c% in diabetes+lycopene group and diabetes group increased (p <0.05) compared to control and only lycopene treated group. The highest level of ACE activity was observed in the (D) group ( p < 0.05). Activity in the (L) group was also significantly greater than in the control group ( p < 0.05). The (DL) group had lower ( p < 0.05). ACE activity than the (D) group. Lycopene implementation was found to be effective in the inhibition of ACE activity, an important indicator of diabetes-related complications.

Lycopene inhibits angiogenesis in human umbilical vein endothelial cells and rat aortic rings

Angiogenesis is important for tumour vascularisation and growth, and is therefore a promising target for cancer therapy. The present study reports inhibition ofin vitroangiogenesis in human umbilical vein endothelial cells (HUVEC) as well as in rat aortic rings at physiological concentrations of lycopene, that is, 1–2 μmol/l. At a final concentration of 1·15 μmol/l, a significant reduction (P < 0·05) in network branching, that is, junction numbers, the number of tubules and tubule length, was observed in both HUVEC as well as in the rat aortic rings. The inhibitory effect of lycopene was independent of the presence of the pro-angiogenic agents, vascular endothelial growth factor and TNF-α. The anti-angiogenic effects of lycopene in the present study were shown at a concentration that should be achievable by dietary means. These results extend our knowledge of one of the putative anti-cancer actions of lycopene.

Cancer chemopreventive effects of lycopene: suppression of MMP-7 expression and cell invasion in human colon cancer cells

Clinical studies indicate that high blood levels of leptin or matrix metalloproteinase-7 (MMP-7; matrilysin) proteins are associated with tumor progression of human colorectal cancer (CRC). Leptin could play an important role in cell migration and invasion of cancer cells. Our previous study indicated that lycopene could inhibit the proliferation of human colon cancer cells in vitro. However, the inhibitory effects of lycopene on the progression of human colon cancer cells have not been demonstrated yet. In this study, we investigated the inhibitory effects of lycopene on tumor progression including cell invasion and MMP-7 expression in leptin-stimulated human colon cancer cells in vitro. Our results demonstrated that lycopene significantly inhibited leptin-mediated cell invasion and MMP-7 expression in human colon cancer HT-29 cells. Lycopene could augment the expression and stability of E-cadherin proteins. Our results showed that MAPK/ERK and PI3K/Akt signaling pathways played important roles in leptin-mediated MMP-7 expression and cell invasion. Lycopene could effectively inhibit the phosphorylation of Akt, glycogen synthase kinase-3β (GSK-3β) and ERK 1/2 proteins. The molecular mechanisms of lycopene were in part through decreases in nuclear levels of AP-1 and β-catenin proteins. These novel findings suggested that lycopene could act as a chemopreventive agent to suppress MMP-7 expression and leptin-mediated cell invasion in human colon cancer HT-29 cells.

Marine carotenoids: biological functions and commercial applications

Carotenoids are the most common pigments in nature and are synthesized by all photosynthetic organisms and fungi. Carotenoids are considered key molecules for life. Light capture, photosynthesis photoprotection, excess light dissipation and quenching of singlet oxygen are among key biological functions of carotenoids relevant for life on earth. Biological properties of carotenoids allow for a wide range of commercial applications. Indeed, recent interest in the carotenoids has been mainly for their nutraceutical properties. A large number of scientific studies have confirmed the benefits of carotenoids to health and their use for this purpose is growing rapidly. In addition, carotenoids have traditionally been used in food and animal feed for their color properties. Carotenoids are also known to improve consumer perception of quality; an example is the addition of carotenoids to fish feed to impart color to farmed salmon.

Effects of lycopene, synbiotic and their association on early biomarkers of rat colon carcinogenesis

This study evaluated whether a synergy exists for the combined treatment with lycopene and synbiotic on early biomarkers of colon carcinogenesis. Male Wistar rats received a diet containing 300 mg/kg of lycopene and/or synbiotic (Bifidobacterium lactisplus oligofructose/inulin) or their combination 2 weeks before and during carcinogen treatment with 1,2-dimethylhydrazine (DMH). Twenty-four hours after the last DMH application, the colons were processed for immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), p53 protein, hematoxylin-eosin staining for apoptosis analysis and genotoxicity of fecal water by comet assay. Eight weeks after the last DMH application, the colons were analyzed for development of classical aberrant crypt foci (ACF) and mucin-negative ACF. Treatment with lycopene, synbiotic or their combination significantly increased apoptosis, reduced the PCNA and p53 labeling indexes and the development of classical ACF and mucin-negative ACF. Furthermore, a lower genotoxicity of fecal water was also detected in the groups treated with the chemopreventive agents. An additive/synergistic effect of the combined treatment with lycopene/synbiotic was observed only for the fecal water genotoxicity and mucin-negative ACF parameters. These results indicate that an additive/synergistic of the combination of chemopreventive agents on the initiation phase of colon carcinogenesis can be detected using selective early biomarkers.

Lycopene inhibits growth of human colon cancer cells via suppression of the Akt signaling pathway

The aberrant regulation of the phosphoinositide 3-kinase/Akt survival signaling pathway in cancer has prompted significant interest in suppression of this pathway to treat cancer. Previous studies identified an important role for phosphoinositide 3-kinase/Akt in colon cancer progression. Lycopene, a major component in tomato, exhibited potential anti-carcinogenic activity. Consumption of tomato has been associated with reduced risk of several types of human cancer. However, the inhibitory mechanisms of lycopene on the proliferation of human colon cancer have not been studied well yet. Thus we investigated the inhibitory effects of lycopene on the Akt signaling pathway in human colon cancer HT-29 cells. Lycopene inhibited cell proliferation in human colon cancer HT-29 cells with a IC(50) value of 10 microM. Lycopene treatment suppressed Akt activation and non-phosphorylated beta-catenin protein level in human colon cancer cells. Immunocytochemical results indicated that lycopene increased the phosphorylated form of beta-catenin proteins. These effects were also associated with reduced promoter activity and protein expression of cyclin D1. Furthermore, lycopene significantly increased nuclear cyclin-dependent kinase inhibitor p27(kip)abundance and inhibited phosphorylation of the retinoblastoma tumor suppressor protein in human colon cancer cells. In conclusion, lycopene inhibited cell proliferation of human colon cancer cells via suppression of the Akt signaling pathway and downstream targeted molecules.

Concomitant supplementation of lycopene and eicosapentaenoic acid inhibits the proliferation of human colon cancer cells

Several studies indicated that people who live in the Mediterranean region have very low rates of chronic diseases such as cardiovascular disease and cancer. It is well known that Mediterranean-style diet is rich in vegetables, tomato, fruit, fish and olive oil. These important dietary components may contribute to lower risk of cancer. Lycopene, a major component in tomato, exhibited potential anticarcinogenic activity. Previous studies showed that consumption of fish containing eicosapentaenoic acid (EPA) correlated with reduced risk of cancer. However, the combined effects of lycopene and EPA on the proliferation of human colon cancer have not been studied well yet. Thus, we investigated the anticancer properties and therapeutic potential of lycopene and EPA in human colon cancer HT-29 cells. In this study, we determined the combined effects of lycopene and EPA on the proliferation of human colon cancer HT-29 cells. We demonstrated that low concentration of lycopene and EPA could synergistically inhibit the proliferation of colon cancer cells. The inhibitory mechanism was associated with suppression of phosphatidylinositol 3-kinase/Akt signaling pathway. Furthermore, treatment of lycopene and EPA also synergistically blocked the activation of downstream mTOR molecule. Immunocytochemical staining results revealed that lycopene and EPA could also up-regulate the expression of apoptotic proteins such as Bax and Fas ligand to suppress cell survival. In conclusion, our novel findings suggest that lycopene and EPA synergistically inhibited the growth of human colon cancer HT-29 cells even at low concentration. The inhibitory effects of lycopene and EPA on cell proliferation of human colon cancer HT-29 cells were, in part, associated with the down-regulation of the PI-3K/Akt/mTOR signaling pathway.

Lycopene in cancer prevention and treatment

Dietary intake of lycopene is inversely associated with the risk of many cancers. Preclinical studies show that lycopene has potent in vitro and in vivo antitumor effects, suggesting potential preventive and therapeutic roles for the compound. However, clinical trials with lycopene have only recently been started, and available clinical data preclude firm conclusions with regard to its use in cancer prevention and treatment. Further mechanistic studies and randomized controlled clinical intervention trials with lycopene involving cancer patients are warranted.

Protective effect of dietary tomatine against dibenzo[a,l]pyrene (DBP)-induced liver and stomach tumors in rainbow trout

The potential anti-carcinogenic effects of tomatine, a mixture of commercial tomato glycoalkaloids alpha-tomatine and dehydrotomatine (10:1), were examined in the rainbow trout chemoprevention model. Prior to the chemoprevention study, a preliminary toxicity study revealed that tomatine in the diet fed daily at doses from 100 to 2000 parts per million (ppm) for 4 weeks was not toxic to trout. For the tumor study, replicate groups of 105 trout were fed diets containing dibenzo[a,l]pyrene (DBP) alone (224 ppm), (N = 3), DBP plus tomatine at 2000 ppm (N = 2), tomatine alone (N = 2), or control diet (N = 2) for 4 weeks. The fish were then returned to control diet for 8 months and necropsied for histopathology. Dietary tomatine was found to reduce DBP-initiated liver tumor incidence from 37.0 to 19.0% and stomach tumor incidence from 46.4 to 29.4%. Tomatine also reduced stomach tumor multiplicity. The tomatine-containing diets did not induce mortality, change in fish weights, or liver weights. No adverse pathological effects in the tissues of the fish on the tomatine diets were observed. Dose-response and chemopreventive mechanisms for tomatine protection remain to be examined. This is the first report on the anticarcinogenic effects of tomatine in vivo.

Selected fruits reduce azoxymethane (AOM)-induced aberrant crypt foci (ACF) in Fisher 344 male rats

Phytochemicals contribute to the vibrant colors of fruits and it is suggested that the darker the fruit the higher the antioxidative or anticarcinogenic properties. In this study we investigated the possible effects of blueberries (BLU), blackberries (BLK), plums (PLM), mangoes (MAN), pomegranate juice (POJ), watermelon juice (WMJ) and cranberry juice (CBJ) on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in Fisher 344 male rats. Forty-eight male Fisher 344 rats were randomly assigned to eight groups (n=6). The groups were fed AIN-93G as a control (C) diet, the rats fed fruits received AIN-93G+5% fruits and the groups that were given fruits juices received 20% fruit juice instead of water. The rats received subcutaneous injections of AOM at 16 mg/kg body weight at seventh and eighth weeks of age. At 17th week of age, the rats were killed by CO(2) asphyxiation. Total ACF numbers (mean+/-SEM) in the rats fed CON, BLU, BLK, PLM, MNG, POJ, WMJ and CBJ were 171.67+/-5.6, 11.33+/-2.85, 24.0+/-0.58, 33.67+/-0.89, 28.67+/-1.33, 15.67+/-1.86, 24.33+/-3.92 and 39.0+/-15.31. Total glutathione-S-transferase (GST) activity (mICROmol/mg) in the liver of the rats fed fruits (except BLK) and fruit juices were significantly (p<0.05) higher in the rats fed fruits and fruit juices compared with the control. Our findings suggest that among the fruits and fruit juices, BLU and POJ contributed to significant (P<0.05) reductions in the formation of AOM-induced ACF.

Plasma carotenoid, alpha-tocopherol and retinol concentrations and risk of colorectal adenomas: A case-control study in Japan

To investigate associations between plasma carotenoids, alpha-tocopherol and retinol with colorectal adenomas risk, we measured concentrations in 224 asymptomatic colorectal adenoma cases and 230 population-based controls matched for age and sex. After adjustment for age, history of colorectal adenomas and cancers, BMI, smoking, drinking status, multivitamin consumption and plasma total cholesterol, the risk of colorectal adenomas in the highest quartile was approximately half of that of men in the lowest quartile for alpha-carotene (OR=0.38; 95% CI: 0.18-0.84; P(trend)=0.01), beta-carotene (OR=0.51; 95% CI: 0.24-1.07; P(trend)=0.03) and total carotenoids (OR=0.48; 95% CI: 0.22-1.03; P(trend)=0.04). In addition, a protective association for alpha-carotene in women was also indicated, but which did not reach statistical significance (OR=0.53; 95% CI: 0.19-1.52; P(trend)=0.35). Our findings suggest a protective effect of carotenoids against the development of colorectal adenomas.

Serum carotenoids, retinol, and tocopherols, and colorectal cancer risk in a Japanese cohort: effect modification by sex for carotenoids

To examine associations of serum carotenoids, retinol, and tocopherols with colorectal cancer risk, we conducted a case-control study nested within the Japan Collaborative Cohort Study. These micronutrients were measured in prediagnostic serum samples from 116 men and women who developed colorectal cancer during an 8-yr follow-up period and from 298 matched controls. In men, the higher level of serum total carotenoids was associated with a decreased risk: The multivariate-adjusted odds ratio (OR) for the highest vs. the lowest tertile was 0.34 (95% confidence interval [CI] = 0.11-1.00; trend P over tertiles = 0.040). In women, the higher levels of alpha- and and total carotenoids were instead related to an increased risk: The corresponding ORs were 4.72 (95% CI = 1.29-17.3), 2.00 (0.70-5.73), and 2.47 (0.73-8.34), respectively (trend P = 0.007, 0.040, and 0.064, respectively). We also found a somewhat decreasing risk with increased serum retinol in all subjects and alpha-tocopherol in men: The ORs (95% CI) for the highest tertiles were 0.29 (0.11-0.78; trend P over tertiles = 0.010) and 0.29 (0.07-1.17; trend P = 0.098), respectively. The effects of some carotenoids on colorectal cancer risk may be modified by sex or by factors associated with sex, including smoking and drinking habits.

Association between 6-n-propylthiouracil (PROP) bitterness and colonic neoplasms

Inadequate vegetable intake appears to increase colon cancer risk. Since genetic variation in taste influences vegetable preference, we tested associations between bitterness of 6-n-propylthiouracil (PROP), a measure of taste genetics, and number of colonic polyps, a measure of colon cancer risk, in 251 men who underwent screening lower endoscopy. Patients used the general Labeled Magnitude Scale to rate bitterness of 1.6 mg PROP delivered via filter paper. A subset of 86 patients reported weekly vegetable intakes, excluding salad or potatoes. PROP bitterness correlated significantly with polyp number, an effect separate from age-associated increases in polyp number. The PROP-polyp relationship was strongest in men over 66 years, and older men with polyps were most likely to be overweight or obese. In the subset reporting vegetable intake, men who tasted PROP as more bitter consumed fewer vegetables. These preliminary findings suggest that taste genetics may influence colon cancer risk, possibly through intake of vegetables.

Exploiting genotypic variation in plant nutrient accumulation to alleviate micronutrient deficiency in populations

More than 2 billion people consume diets that are less diverse than 30 years ago, leading to deficiencies in micronutrients, especially iron (Fe), zinc (Zn), selenium (Se), iodine (I), and also vitamin A. A strategy that exploits genetic variability to breed staple crops with enhanced ability to fortify themselves with micronutrients (genetic biofortification) offers a sustainable, cost-effective alternative to conventional supplementation and fortification programs. This is more likely to reach those most in need, has the added advantages of requiring no change in current consumer behaviour to be effective, and is transportable to a range of countries. Research by our group, along with studies elsewhere, has demonstrated conclusively that substantial genotypic variation exists in nutrient (e.g. Fe, Zn) and nutrient promotor (e.g. inulin) concentrations in wheat and other staple foods. A rapid screening technique has been developed for lutein content of wheat and triticale, and also for pro-vitamin A carotenoids in bread wheat. This will allow cost-effective screening of a wider range of genotypes that may reveal greater genotypic variation in these traits. Moreover, deeper understanding of genetic control mechanisms and development of molecular markers will facilitate breeding programs. We suggest that a combined strategy utilising plant breeding for higher micronutrient density; maximising the effects of nutritional promoters (e.g. inulin, vitamin C) by promoting favourable dietary combinations, as well as by plant breeding; and agronomic biofortification (e.g. adding iodide or iodate as fertiliser; applying selenate to cereal crops by spraying or adding to fertiliser) is likely to be the most effective way to improve the nutrition of populations. Furthermore, the importance of detecting and exploiting beneficial interactions is illustrated by our discovery that in Fe-deficient chickens, circulating Fe concentrations can be restored to normal levels by lutein supplementation. Further bioavailability/bioefficacy trials with animals and humans are needed, using varying dietary concentrations of Fe, Zn, carotenoids, inulin, Se and I to elucidate other important interactions in order to optimise delivery in biofortification programs.

Carotenoids, vitamin A and risk of adenomatous polyp recurrence in the polyp prevention trial

One trial reported beta-carotene supplementation was protective of adenomatous polyp recurrence in nonsmokers. We now examine the relation of serum and dietary carotenoids and vitamin A to adenomatous polyp recurrence in a subcohort of 834 participants in a low fat, high fiber, high fruit and vegetable dietary intervention, the Polyp Prevention Trial. Multivariate odds ratio (OR) and 95% confidence intervals (CI) of polyp recurrence were obtained using baseline or the average (first 3 years of the trial) carotenoid and vitamin A values after adjustment for covariates. Compared to the lowest quartile of baseline alpha-carotene concentrations, the OR of multiple polyp recurrence for the highest quartile was 0.55 (95% CI = 0.30-0.99) and the OR of right-sided recurrence was 0.60 (95% CI = 0.37-0.95). Baseline dietary intakes of alpha-carotene and vitamin A from food with/without supplements were inversely associated with any recurrence (p for linear trend = 0.03-alpha-carotene; p = 0.004 and p = 0.007 -intakes of vitamin A). Compared to the lowest quartile of averaged beta-carotene concentrations, the OR of multiple adenomas for the highest quartile was 0.40 (95% CI = 0.22-0.75) with an inverse trend (p = 0.02). The risk was inversely related to averaged: alpha-carotene concentrations and right-sided polyps; alpha-carotene intake and recurrence of any, multiple and right-sided polyps; beta-carotene intake and multiple adenoma recurrence; vitamin A from food (with supplements) and each adverse endpoint. Thus, alpha-carotene and vitamin A may protect against recurrence in nonsmokers and nondrinkers or be indicative of compliance or another healthy lifestyle factor that reduces risk.

Carotenoids and chronic diseases

Chronic diseases such as cancer and cardiovascular diseases are the major causes of deaths in North America. Dietary intake of fruits and vegetables has been suggested to have protective effects against such chronic diseases. Carotenoids are important plant pigments which are thought to contribute towards the beneficial effects of fruit and vegetable consumption. This review focuses on the role of carotenoids and particularly lycopene in chronic diseases.