Dietary lycopene and tomato extract supplementations inhibit nonalcoholic steatohepatitis-promoted hepatocarcinogenesis in rats

The Potential of Non-Provitamin A Carotenoids for the Prevention and Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is an obesity-associated spectrum of comorbidities defined by the presence of metabolic dysfunction, oxidative stress, inflammation, and fibrosis in the liver. If left untreated, NAFLD can progress to cirrhosis, liver failure, or hepatocellular carcinoma. NAFLD is recognized as the most common liver disease in the United States, affecting around 30% of the population. Identification of dietary components capable of reducing or preventing NAFLD is therefore essential to battle this condition. Dietary carotenoids including astaxanthin, lycopene, lutein, and zeaxanthin have been demonstrated to be potent antioxidants as well as to exhibit anti-inflammatory effects. Many studies report the protective effect(s) of these carotenoids against different conditions such as atherosclerosis, diabetic complications, age-related macular degeneration, and liver diseases. In this review, we will focus on the effects of these carotenoids in the prevention or reduction of NAFLD as seen in epidemiological observations and clinical trials, as well as the suggested mechanism of action derived from animal and cell studies.

Tomato Juice Consumption Modifies the Urinary Peptide Profile in Sprague-Dawley Rats with Induced Hepatic Steatosis

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder in Western countries, with a high prevalence, and has been shown to increase the risk of type 2 diabetes, cardiovascular disease (CVD), etc. Tomato products contain several natural antioxidants, including lycopene—which has displayed a preventive effect on the development of steatosis and CVD. Accordingly, the aim of the present work was to evaluate the effect of tomato juice consumption on the urinary peptide profile in rats with NAFLD induced by an atherogenic diet and to identify potential peptide biomarkers for diagnosis. Urine samples, collected weekly for four weeks, were analyzed by capillary electrophoresis (CE) coupled to a mass spectrometer (MS). A partial least squares-discriminant analysis (PLS-DA) was carried out to explore the association between differential peptides and treatments. Among the 888 peptides initially identified, a total of 55 were obtained as potential biomarkers. Rats with steatosis after tomato juice intake showed a profile intermediate between that of healthy rats and that of rats with induced hepatic steatosis. Accordingly, tomato products could be considered as a dietary strategy for the impairment of NAFLD, although further research should be carried out to develop a specific biomarkers panel for NAFLD.

Tobacco carcinogen induces both lung cancer and non-alcoholic steatohepatitis and hepatocellular carcinomas in ferrets which can be attenuated by lycopene supplementation

Early epidemiologic studies have reported that tobacco smoking, which is causally associated with liver cancer, is an independent risk factor for non-alcoholic fatty liver diseases (NAFLD). Lycopene from tomatoes has been shown to be a potential preventive agent against NAFLD and hepatocellular carcinoma (HCC). In the present study, we investigated whether the tobacco carcinogen 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces lesions in both lungs and livers of ferrets with or without lycopene intervention. Male ferrets (6 groups, n = 8-10) were treated either with NNK (50 mg/kg BW, i.p., once a month for four consecutive months) or saline with or without dietary lycopene supplementation (2.2 and 6.6 mg/kg BW/day, respectively) for 26 weeks. Results demonstrate that NNK exposure results in higher incidences of lung tumors, HCC and steatohepatitis (which is characterized by severe inflammatory cell infiltration with concurrent fat accumulation in liver, hepatocellular ballooning degeneration and increased NF-κB expression), as well as elevations in bilirubin and AST levels in ferrets. Lycopene supplementation at two doses prevented NNK-induced expressions of α7 nicotinic acetylcholine receptor in the lung and NF-κB and CYP2E1 in the liver and attenuated the NNK-induced mortality and pathological lesions in both the lungs and livers of ferrets. The present study provided strong experimental evidence that the tobacco carcinogen NNK can induce both HCC and steatohepatitis in the ferrets and can be a useful model for studying tobacco carcinogen-associated NAFLD and liver cancer. Furthermore, lycopene could provide potential benefits against smoke carcinogen-induced pulmonary and hepatic injury.

Resistin mediates tomato and broccoli extract effects on glucose homeostasis in high fat diet-induced obesity in rats

Background

Resistin is an adipocyte hormone that regulates glucose metabolism. Elevated levels of resistin may cause insulin resistance. This may link obesity, and increased fat mass to type II diabetes and insulin resistance. We hypothesized that treatment with tomato and broccoli extracts regulates glucose homeostasis via modulation of resistin levels in high fat diet-induced obesity rats (HFD).

Methods

Forty-eight male albino rats were divided into 8 groups as follows: control, HFD, stop fat diet (SD), Tomato 200 mg/kg (T200), Tomato 400 mg/kg (T400), Broccoli 200 mg/kg (B200), Broccoli 400 mg/kg (B400), and Chromax (CX). Treatment continued for 1 month. Serum levels of resistin, leptin, adiponectin, glucose and insulin were measured using ELISA and spectrophotometry.

Results

Serum levels of resistin were significantly reduced in the T 200, T 400, B 200, B 400 and CX groups to: 4.13 ± 0.22 ng/ml, 1.51 ± 0.04 ng/ml, 4.13 ± 0.22 ng/ml, 2.32 ± 0.15 ng/ml and 1.37 ± 0.03 ng/ml, respectively, compared to HFD group and SD group (P value < 0.0001). Non-significant differences were found between T 400, B 400 and CX groups. Serum levels of leptin were significantly reduced in the T 400 (22.7 ± 0.84 pg/ml) group compared to the B 400 (41 ± 2.45 Pg/ml) and CX groups (45.7 ± 2.91 Pg/ml), P value < 0.001. Serum levels of adiponectin were significantly increased in the T 400 group (131 ± 3.84 pg/ml) compared to the CX group (112 ± 4.77 pg/ml), P value < 0.01.

Conclusions

Our results demonstrate that tomato and broccoli extract treatment regulates glucose homeostasis via reduction of serum resistin and may be a useful non-pharmacological therapy for obesity.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1203-0) contains supplementary material, which is available to authorized users.

Novel Action of Carotenoids on Non-Alcoholic Fatty Liver Disease: Macrophage Polarization and Liver Homeostasis

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. It is characterized by a wide spectrum of hepatic changes, which may progress to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFLD is considered a hepatic manifestation of metabolic syndrome; however, mechanisms underlying the onset and progression of NAFLD are still unclear. Resident and recruited macrophages are key players in the homeostatic function of the liver and in the progression of NAFLD to NASH. Progress has been made in understanding the molecular mechanisms underlying the polarized activation of macrophages. New NAFLD therapies will likely involve modification of macrophage polarization by restraining M1 activation or driving M2 activation. Carotenoids are potent antioxidants and anti-inflammatory micronutrients that have been used to prevent and treat NAFLD. In addition to their antioxidative action, carotenoids can regulate macrophage polarization and thereby halt the progression of NASH. In this review, we summarize the molecular mechanisms of macrophage polarization and the function of liver macrophages/Kupffer cells in NAFLD. From our review, we propose that dietary carotenoids, such as β-cryptoxanthin and astaxanthin, be used to prevent or treat NAFLD through the regulation of macrophage polarization and liver homeostasis.

Dietary Natural Products for Prevention and Treatment of Liver Cancer

Liver cancer is the most common malignancy of the digestive system with high death rate. Accumulating evidences suggests that many dietary natural products are potential sources for prevention and treatment of liver cancer, such as grapes, black currant, plum, pomegranate, cruciferous vegetables, French beans, tomatoes, asparagus, garlic, turmeric, ginger, soy, rice bran, and some edible macro-fungi. These dietary natural products and their active components could affect the development and progression of liver cancer in various ways, such as inhibiting tumor cell growth and metastasis, protecting against liver carcinogens, immunomodulating and enhancing effects of chemotherapeutic drugs. This review summarizes the potential prevention and treatment activities of dietary natural products and their major bioactive constituents on liver cancer, and discusses possible mechanisms of action.

Carotenoids and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a growing health problem around the world, especially in developed countries. NAFLD includes all cases of fatty liver disease from simple steatosis to cirrhosis, without excessive alcohol intake, use of steatogenic medication or hereditary disorders. Pathogenesis is associated with dietary high fat intake, decreased free fatty acid (FFA) oxidation, increased hepatic lipogenesis and lipolysis from the adipose tissue. These metabolic alterations contribute to the hepatic fat accumulation. Consequently, stimulated oxidative stress and inflammation play a major role in hepatocellular damage. Therefore, antioxidant and anti-inflammatory agents may have a role in the prevention of this disease. Carotenoids are potent antioxidant and anti-inflammatory micronutrients, which have been investigated in the prevention and treatment of NAFLD. The main sources of the carotenoids are fruits and vegetables. In this article we review the potential role and possible molecular mechanism of carotenoids in NAFLD.

Efficacy of tomato concentrates in mouse models of dyslipidemia and cancer

We previously reported that adding freeze-dried tomato powder from transgenic plants expressing the apolipoprotein A-I mimetic peptide 6F at 2.2% by weight to a Western diet (WD) ameliorated dyslipidemia and atherosclerosis in mice. The same dose in a human would require three cups of tomato powder three times daily. To reduce the volume, we sought a method to concentrate 6F. Remarkably, extracting the transgenic freeze-dried tomato overnight in ethyl acetate with 5% acetic acid resulted in a 37-fold reduction in the amount of transgenic tomato needed for biologic activity. In a mouse model of dyslipidemia, adding 0.06% by weight of the tomato concentrate expressing the 6F peptide (Tg6F) to a WD significantly reduced plasma total cholesterol and triglycerides (P < 0.0065). In a mouse model of colon cancer metastatic to the lungs, adding 0.06% of Tg6F, but not a control tomato concentrate (EV), to standard mouse chow reduced tumor-associated neutrophils by 94 ± 1.1% (P = 0.0052), and reduced tumor burden by two-thirds (P = 0.0371). Adding 0.06% of either EV or Tg6F by weight to standard mouse chow significantly reduced tumor burden in a mouse model of ovarian cancer; however, Tg6F was significantly more effective (35% reduction for EV vs. 53% reduction for Tg6F; P = 0.0069). Providing the same dose of tomato concentrate to humans would require only two tablespoons three times daily making this a practical approach for testing oral apoA-I mimetic therapy in the treatment of dyslipidemia and cancer.

Lutein prevents high fat diet-induced atherosclerosis in ApoE-deficient mice by inhibiting NADPH oxidase and increasing PPAR expression

Epidemiological and experimental studies provide supportive evidence that lutein, a major carotenoid, may act as a chemopreventive agent against atherosclerosis, although the underlying molecular mechanisms are not well understood. The main aim of this study was to investigate the effects of lutein on the alleviation of atherosclerosis and its molecular mechanisms involved in oxidative stress and lipid metabolism. Male apolipoprotein E knockout mice (n = 55) were fed either a normal chow diet or a high fat diet (HFD) supplemented with or without lutein for 24 weeks. The results showed that a HFD induced atherosclerosis formation, lipid metabolism disorders and oxidative stress, but noticeable improvements were observed in the lutein treated group. Additionally, lutein supplementation reversed the decreased protein expression of aortic heme oxygenase-1 and increased the mRNA and protein expressions of aortic nicotinamide-adenine dinucleotide phosphate oxidase stimulated by a HFD. Furthermore, the decreased mRNA and protein expression levels of hepatic peroxisome proliferator-activated receptor-α, carnitine palmitoyltransferase 1A, acyl CoA oxidase 1, low density lipoprotein receptors and scavenger receptor class B type I observed in mice with atherosclerosis were markedly enhanced after treatment with lutein. Taken together, these data add new evidence supporting the anti-atherogenic properties of lutein and describing its mechanisms of action in atherosclerosis prevention, including oxidative stress and lipid metabolism improvements.

Lycopene-rich tomato oleoresin modulates plasma adiponectin concentration and mRNA levels of adiponectin, SIRT1, and FoxO1 in adipose tissue of obese rats

Aim:

To investigate whether lycopene can modulate adiponectin levels and SIRT1 and FoxO1 gene expression in the adipose tissue of diet-induced obese rats.

Methods:

Male Wistar rats were first fed with hypercaloric diet (HD, n = 12) for 6 weeks, and afterward, these rats were randomly assigned to receive HD ( n = 6) or HD with lycopene-rich tomato oleoresin (equivalent to lycopene 10 mg/kg body weight (BW)/day, HD + L, n = 6) by gavage for additional 6 weeks. Plasma lycopene and adiponectin levels were analyzed by high-performance liquid chromatography and immunoassay, respectively. The messenger RNA (mRNA) expressions of adiponectin, Sirtuin 1 (SIRT1), Forkhead box O 1 (FoxO1), fatty acid translocase/cluster of differentiation 36 (FAT/CD36), and PPARγ in adipose tissues were determined by quantitative polymerase chain reaction.

Results:

Lycopene was detected in the plasma of rats in HD + L group but not in the HD group. Although both BW and adiposity were not different between the two groups, there was a significant increase in both plasma concentration and mRNA expression of adiponectin in the adipose tissue of the HD + L group. In addition, the lycopene supplementation upregulated mRNA expressions of SIRT1, FoxO1, and FAT/CD36 but downregulated PPARγ in adipose tissue of obese rats.

Conclusion:

These data suggest that lycopene, in the concentration used, is not toxic and also its health benefits in adipose tissue may play a role against obesity-related complications.

Dietary tomato powder inhibits alcohol-induced hepatic injury by suppressing cytochrome p450 2E1 induction in rodent models

Chronic and excessive alcohol consumption leads to the development of alcoholic liver disease (ALD) and greatly increases the risk of liver cancer. Induction of the cytochrome p450 2E1 (CYP2E1) enzyme by chronic and excessive alcohol intake is known to play a role in the pathogenesis of ALD. High intake of tomatoes, rich in the carotenoid lycopene, is associated with a decreased risk of chronic disease. We investigated the effects of whole tomato (tomato powder, TP), partial tomato (tomato extract, TE), and purified lycopene (LYC) against ALD development in rats. Of the three supplements, only TP reduced the severity of alcohol-induced steatosis, hepatic inflammatory foci, and CYP2E1 protein levels. TE had no effect on these outcomes and LYC greatly increased inflammatory foci in alcohol-fed rats. To further support the protective effect of TP against ALD, TP was supplemented in a carcinogen (diethylnitrosamine, DEN)-initiated alcohol-promoted mouse model. In addition to reduced steatosis and inflammatory foci, TP abolished the presence of preneoplastic foci of altered hepatocytes in DEN-injected mice fed alcohol. These reductions were associated with decreased hepatic CYP2E1 protein levels, restored levels of peroxisome proliferator-activated receptor-α and downstream gene expression, decreased inflammatory gene expression, and reduced endoplasmic reticulum stress markers. These data provide strong evidence for TP as an effective whole food prevention strategy against ALD.

Lycopene attenuated hepatic tumorigenesis via differential mechanisms depending on carotenoid cleavage enzyme in mice

Obesity is associated with increased liver cancer risks and mortality. We recently showed that apo-10'-lycopenoic acid, a lycopene metabolite generated by beta-carotene-9',10'-oxygenase (BCO2), inhibited carcinogen-initiated, high-fat diet (HFD)-promoted liver inflammation, and hepatic tumorigenesis development. The present investigation examined the outstanding question of whether lycopene could suppress HFD-promoted hepatocellular carcinoma (HCC) progression, and if BCO2 expression is important using BCO2-knockout (BCO2-KO) and wild-type male mice. Results showed that lycopene supplementation (100 mg/kg diet) for 24 weeks resulted in comparable accumulation of hepatic lycopene (19.4 vs. 18.2 nmol/g) and had similar effects on suppressing HFD-promoted HCC incidence (19% vs. 20%) and multiplicity (58% vs. 62%) in wild-type and BCO2-KO mice, respectively. Intriguingly, lycopene chemopreventive effects in wild-type mice were associated with reduced hepatic proinflammatory signaling (phosphorylation of NK-κB p65 and STAT3; IL6 protein) and inflammatory foci. In contrast, the protective effects of lycopene in BCO2-KO but not in wild-type mice were associated with reduced hepatic endoplasmic reticulum stress-mediated unfolded protein response (ER(UPR)), through decreasing ER(UPR)-mediated protein kinase RNA-activated like kinase-eukaryotic initiation factor 2α activation, and inositol requiring 1α-X-box-binding protein 1 signaling. Lycopene supplementation in BCO2-KO mice suppressed oncogenic signals, including Met mRNA, β-catenin protein, and mTOR complex 1 activation, which was associated with increased hepatic microRNA (miR)-199a/b and miR214 levels. These results provided novel experimental evidence that dietary lycopene can prevent HFD-promoted HCC incidence and multiplicity in mice, and may elicit different mechanisms depending on BCO2 expression.

Effect of rye bread enriched with tomato pomace on fat absorption and lipid metabolism in rats fed a high-fat diet

BACKGROUND

Tomato pomace (TP), obtained as a residue of tomato processing, was used to enrich rye bread (RB). The sensory profile of this functional bread (RB+TP) was characterised, and its fat absorption and lipid metabolism properties in high-fat-fed rats were studied.

RESULTS

Intake of the HF diet containing RB, RB+TP, or TP alone increased faecal energy and fat excretion, but did not affect animal growth or visceral fat weight. Both RB and RB+TP diminished the negative impact of the HF diet, lowering the atherogenic index of plasma (AIP) and the total liver lipid contents by 31.6% and 24%, respectively. The experimental diets had no effect on liver S-adenosylhomocysteine (SAH) concentrations or on the S-adenosylmethionine (SAM) to SAH ratio, though the lowest SAM levels were observed in the HF+TP group. No significant differences were detected in blood homocysteine, triglycerides, glucose or insulin levels.

CONCLUSIONS

Although RB+TP incorporated into a HF diet may lead to a decrease in AIP and total liver lipid content, this effect does not depend on the components of TP, but rather on the RB ingredients. However, pure TP, in the doses used in this study, may potentially play a role in the energy balance via faecal loss of lipids.

Carotenoid derivatives inhibit nuclear factor kappa B activity in bone and cancer cells by targeting key thiol groups

Aberrant activation of the nuclear factor kappa B (NFkB) transcription system contributes to cancer progression, and has a harmful effect on bone health. Several major components of the NFkB pathway such as IkB Kinase (IKK) and the NFkB subunits contain cysteine residues that are critical for their activity. The interaction of electrophiles with these cysteine residues results in NFkB inhibition. Carotenoids, hydrophobic plant pigments, are devoid of electrophilic groups, and we have previously demonstrated that carotenoid derivatives, but not the native compounds activate the Nrf2 transcription system. The aim of the current study was to examine whether carotenoid derivatives inhibit NFkB, and, if so, to determine the molecular mechanism underpinning the inhibitory action. We report in the present study that a mixture of oxidized derivatives, prepared by ethanol extraction from partially oxidized lycopene preparation, inhibited NFkB reporter gene activity. In contrast, the intact carotenoid was inactive. A series of synthetic dialdehyde carotenoid derivatives inhibited reporter activity as well as several stages of the NFkB pathway in both cancer and bone cells. The activity of the carotenoid derivatives depended on the reactivity of the electrophilic groups in reactions such as Michael addition to sulfhydryl groups of proteins. Specifically, carotenoid derivatives directly interacted with two key proteins of the NFkB pathway: the IKKβ and the p65 subunit. Direct interaction with IKKβ was found in an in vitro kinase assay with a recombinant enzyme. The inhibition by carotenoid derivatives of p65 transcriptional activity was observed in a reporter gene assay performed in the presence of excess p65. This inhibition action resulted, at least in part, from direct interaction of the carotenoid derivative with p65 leading to reduced binding of the protein to DNA as evidenced by electrophoretic mobility shift assay (EMSA) experiments. Importantly, we found by using mutation in key cysteine residues of both p65 and IKK that specific thiol groups are essential for NFkB inhibition by carotenoid derivatives. In conclusion, we propose that electrophilic carotenoid derivatives contribute to cancer prevention as well as bone health maintenance via the inhibition of the NFkB transcription system. Pivotal thiol groups of both IKK and p65 play a key role in this process.

The role of inflammation and liver cancer

Persistent inflammation is known to promote and exacerbate malignancy. Primary liver cancer, mostly hepatocellular carcinoma (HCC), is a clear example of inflammation-related cancer as more than 90 % of HCCs arise in the context of hepatic injury and inflammation. HCC represents the fifth most common malignancy and the third leading cause of cancer-related death worldwide with about one million new cases diagnosed every year with almost an equal number of deaths. Chronic unresolved inflammation is associated with persistent hepatic injury and concurrent regeneration, leading to sequential development of fibrosis, cirrhosis, and eventually HCC. Irrespective of the intrinsic differences among various etiological factors, a common denominator at the origin of HCC is the perpetuation of a wound-healing response activated by parenchymal cell death and the resulting inflammatory cascade. Hence, the identification of fundamental inflammatory signaling pathways causing transition from chronic liver injury to dysplasia and HCC could depict new predictive biomarkers and targets to identify and treat patients with chronic liver inflammation. This chapter critically discusses the roles of several major cytokines, chemokines, growth factors, transcription factors, and enzymes as well as a distinct network of inflammatory signaling pathways in the development and progression of HCC. It also highlights and analyzes preclinical animal studies showing innovative approaches of targeting inflammatory mediators and signaling by a variety of natural compounds and synthetic agents to achieve effective therapy as well as prevention of hepatic malignancy. Additionally, current limitations and potential challenges associated with the inhibition of inflammatory signaling as well as future directions of research to accelerate clinical development of anti-inflammatory agents to prevent and treat liver cancer are presented.

β-Carotene-9',10'-oxygenase status modulates the impact of dietary tomato and lycopene on hepatic nuclear receptor-, stress-, and metabolism-related gene expression in mice

Tomato and lycopene (ψ,ψ-carotene) consumption is hypothesized to protect against nonalcoholic steatohepatitis and hepatocarcinogenesis, processes that may depend upon diet and gene interactions. To investigate the interaction of tomato or lycopene feeding with β-carotene-9',10'-monooxygenase (Bco2) on hepatic metabolic and signaling pathways, male wild-type (WT) and Bco2(-/-) mice (3-wk-old; n = 36) were fed semi-purified control, 10% tomato powder-containing, or 0.25% lycopene beadlet-containing diets for 3 wk. Serum lycopene concentrations were higher in lycopene- and tomato-fed Bco2(-/-) mice compared with WT (P = 0.03). Tomato- and lycopene-fed mice had detectable hepatic apolipoprotein (apo)-6'-, apo-8'-, and apo-12'-lycopenal concentrations. Hepatic expression of β-carotene-15,15'-monooxygenase was increased in Bco2(-/-) mice compared with WT (P = 0.02), but not affected by diet. Evaluation of hepatic gene expression by focused quantitative reverse transcriptase-polymerase chain reaction arrays for nuclear receptors and coregulators (84 genes) and stress and metabolism (82 genes) genes indicates that tomato feeding affected 31 genes (≥1.5-fold, P < 0.05) and lycopene feeding affected 19 genes, 16 of which were affected by both diets. Lycopene down-regulation of 7 nuclear receptors and coregulators, estrogen-related receptor-α, histone deacetylase 3, nuclear receptor coactivator 4, RevErbA-β, glucocorticoid receptor, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ, coactivator 1 β was dependent upon interaction with Bco2 status. Lycopene and tomato feeding induced gene expression patterns consistent with decreased lipid uptake, decreased cell proliferation and mitosis, down-regulated aryl hydrocarbon receptor signaling, and decreased expression of genes involved in retinoid X receptor heterodimer activation. Tomato feeding also caused expression changes consistent with down-regulation of DNA synthesis and terpenoid metabolism. These data suggest tomato components, particularly lycopene, affect hepatic gene expression, potentially affecting hepatic responses to metabolic, infectious, or chemical stress.

Nutrigenetics of carotenoid metabolism in the chicken: a polymorphism at the β,β-carotene 15,15'-mono-oxygenase 1 (BCMO1) locus affects the response to dietary β-carotene

The enzyme β,β-carotene-15,15'-mono-oxygenase 1 (BCMO1) is responsible for the symmetrical cleavage of β-carotene into retinal. We identified a polymorphism in the promoter of the BCMO1 gene, inducing differences in BCMO1 mRNA levels (high in adenines (AA) and low in guanines (GG)) and colour in chicken breast muscle. The present study was designed to test whether this polymorphism could affect the response to dietary β-carotene. Dietary β-carotene supplementation did not change the effects of the genotypes on breast muscle properties: BCMO1 mRNA levels were lower and xanthophyll contents higher in GG than in AA chickens. Lower vitamin E levels in the plasma and duodenum, plasma cholesterol levels and body weight were also observed in GG than in AA chickens. In both genotypes, dietary β-carotene increased vitamin A storage in the liver; however, it reduced numerous parameters such as SCARB1 (scavenger receptor class B type I) in the duodenum, BCMO1 in the liver, vitamin E levels in the plasma and tissues, xanthophyll contents in the pectoralis major muscle and carcass adiposity. However, several diet × genotype interactions were observed. In the GG genotype, dietary β-carotene increased ISX (intestine-specific homeobox) and decreased BCMO1 mRNA levels in the duodenum, decreased xanthophyll concentrations in the duodenum, liver and plasma, and decreased colour index and HDL-cholesterol concentration in the plasma. Retinol accumulation following dietary β-carotene supplementation was observed in the duodenum of AA chickens only. Therefore, the negative feedback control on β-carotene conversion through ISX appears as functional in the duodenum of GG but not of AA chickens. This could result in a higher availability of β-carotene in the duodenum of GG chickens, reducing the uptake of xanthophylls, liposoluble vitamins and cholesterol.

Non-alcoholic steatohepatitis and hepatocellular carcinoma: implications for lycopene intervention

Increased prevalence of non-alcoholic fatty liver disease (NAFLD) is one of the consequences of the current obesity epidemic. NAFLD is a major form of chronic liver disease that is highly prevalent in obese and overweight adults and children. Nonalcoholic steatohepatitis (NASH) is the severe form of NAFLD, and uncontrolled inflammation as displayed in NASH has been identified as one of the key events in enhancing hepatic carcinogenesis. Lycopene is a non-provitamin A carotenoid and the pigment principally responsible for the characteristic deep-red color of ripe tomato and tomato products, as well as some fruits and vegetables. Lycopene's innate antioxidant and anti-inflammatory properties have generated research interests on its capacity to protect against human diseases that are associated with oxidative stress and inflammation. In addition, differential mechanisms of lycopene metabolism including endogenous cleavage by carotenoid cleavage oxygenases (BCOs), generate lycopene metabolites that may also have significant impact on human disease development. However, it remains to be elucidated as to whether lycopene or its metabolites apolycopenoids have protective effects against obesity-related complications including inflammation and tumorigenesis. This article summarizes the in vivo experiments that elucidated molecular mechanisms associated with obesity-related hepatic inflammation and carcinogenesis. This review also provides an overview of lycopene metabolism, and the molecular pathways involved in the potential beneficial properties of lycopene and apolycopenoids. More research is clearly needed to fully unravel the importance of BCOs in tomato carotenoid metabolism and the consequence on human health and diseases.

(-)-Epigallocatechin-3-gallate suppresses hepatic preneoplastic lesions developed in a novel rat model of non-alcoholic steatohepatitis

PURPOSE

Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to non-alcoholic steatohepatitis (NASH). NASH, which is accompanied by increased oxidative stress and inflammation in the liver, is associated with hepatic carcinogenesis. Green tea catechins (GTCs) possess anti-oxidant, anti-inflammatory, and cancer-preventive properties. In this study, we investigated whether (-)-epigallocatechin-3-gallate (EGCG), a major component of GTCs, inhibits NAFLD/NASH-related liver tumorigenesis.

METHODS

Male 8-week-old Sprague-Dawley (SD) rats were administered a single intraperitoneal injection of a hepatic carcinogen diethylnitrosamine (DEN, 30 mg/kg body weight) and then fed a high-fat diet (HFD) for 7 weeks. The rats were also provided tap water containing 0.01% or 0.1% EGCG during the experiment.

RESULTS

At sacrifice, the livers of SD rats treated with DEN and HFD exhibited marked development of glutathione S-transferase placental form (GST-P)-positive foci, a hepatic preneoplastic lesion, and this was associated with hepatic steatosis, oxidative stress and inflammation, and hepatocyte proliferation. EGCG administration, however, inhibited the development of GST-P-positive foci by decreasing hepatic triglyceride content, reducing hepatic fibrosis, lowering oxidative stress, attenuating inflammation, and inhibiting excessive hepatocyte proliferation in DEN- and HFD-treated SD rats. These findings suggest that the experimental model of SD rats treated with HFD and DEN, in which histopathological and pathophysiological characteristics of NASH and the development of hepatic premalignant lesions were observed, might facilitate the evaluation of liver tumorigenesis associated with NAFLD/NASH.

CONCLUSIONS

Administering EGCG, a GTC, might serve as an effective chemoprevention modality for NAFLD/NASH-related liver tumorigenesis.

Chemoprevention of nonalcoholic fatty liver disease by dietary natural compounds

Nonalcoholic fatty liver disease (NAFLD) refers to a wide spectrum of liver disease that is not from excess alcohol consumption, but is often associated with obesity, type 2 diabetes, and metabolic syndrome. NAFLD pathogenesis is complicated and involves oxidative stress, lipotoxicity, mitochondrial damage, insulin resistance, inflammation, and excessive dietary fat intake, which increase hepatic lipid influx and de novo lipogenesis and impair insulin signaling, thus promoting hepatic triglyceride accumulation and ultimately NAFLD. Overproduction of proinflammatory adipokines from adipose tissue also affects hepatic metabolic function. Current NAFLD therapies are limited; thus, much attention has been focused on identification of potential dietary substances from fruits, vegetables, and edible plants to provide a new strategy for NAFLD treatment. Dietary natural compounds, such as carotenoids, omega-3-PUFAs, flavonoids, isothiocyanates, terpenoids, curcumin, and resveratrol, act through a variety of mechanisms to prevent and improve NAFLD. Here, we summarize and briefly discuss the currently known targets and signaling pathways as well as the role of dietary natural compounds that interfere with NAFLD pathogenesis.

Toxicity of ochratoxin a and its modulation by antioxidants: a review

Ochratoxin A (OTA) is a mycotoxin involved in the development of different types of cancers in rats, mice and humans. A growing number of in vitro and in vivo studies has been collected and has described evidence compatible with a role for oxidative stress in OTA toxicity and carcinogenicity. Because the contribution of the oxidative stress response in the development of cancers is well established, a role in OTA carcinogenicity is plausible. Several studies have been performed to try to counteract the adverse effects of oxygen radicals generated under OTA-exposure. A number of molecules with various antioxidant properties were tested, using in vivo or in vitro models. Protection against OTA-induced DNA damage, lipid peroxidation, as well as cytotoxicity were observed, further confirming the link between OTA toxicity and oxidative damage. These studies demonstrated that antioxidants are able to counteract the deleterious effects of chronic consumption or exposure to OTA and confirmed the potential effectiveness of dietary strategies to counteract OTA toxicity.

Lycopene metabolite, apo-10'-lycopenoic acid, inhibits diethylnitrosamine-initiated, high fat diet-promoted hepatic inflammation and tumorigenesis in mice

Obesity is associated with increased risk in hepatocellular carcinoma (HCC) development and mortality. An important disease control strategy is the prevention of obesity-related hepatic inflammation and tumorigenesis by dietary means. Here, we report that apo-10'-lycopenoic acid (APO10LA), a cleavage metabolite of lycopene at its 9',10'-double bond by carotene-9',10'-oxygenase, functions as an effective chemopreventative agent against hepatic tumorigenesis and inflammation. APO10LA treatment on human liver THLE-2 and HuH7 cells dose dependently inhibited cell growth and upregulated sirtuin 1 (SIRT1), a NAD(+)-dependent protein deacetylase that may suppress hepatic carcinogenesis. This observed SIRT1 induction was associated with decreased cyclin D1 protein, increased cyclin-dependent kinase inhibitor p21 protein expression, and induced apoptosis. APO10LA supplementation (10 mg/kg diet) for 24 weeks significantly reduced diethylnitrosamine-initiated, high fat diet (HFD)-promoted hepatic tumorigenesis (50% reduction in tumor multiplicity; 65% in volume) and lung tumor incidence (85% reduction) in C57Bl/6J mice. The chemopreventative effects of APO10LA were associated with increased hepatic SIRT1 protein and deacetylation of SIRT1 targets, as well as with decreased caspase-1 activation and SIRT1 protein cleavage. APO10LA supplementation in diet improved glucose intolerance and reduced hepatic inflammation [decreased inflammatory foci, TNFα, interleukin (IL)-6, NF-κB p65 protein expression, and STAT3 activation] in HFD-fed mice. Furthermore, APO10LA suppressed Akt activation, cyclin D1 gene, and protein expression and promoted PARP protein cleavage in transformed cells within liver tumors. Taken together, these data indicate that APO10LA can effectively inhibit HFD-promoted hepatic tumorigenesis by stimulating SIRT1 signaling while reducing hepatic inflammation.

The expanding role of fish models in understanding non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a condition in which excessive fat accumulates in the liver of an individual who has not consumed excessive alcohol. Non-alcoholic steatohepatitis (NASH), a severe form of NAFLD, can progress to hepatic cirrhosis and/or hepatocellular carcinoma (HCC). NAFLD is considered to be a hepatic manifestation of metabolic syndrome, and its incidence has risen worldwide in lockstep with the increased global prevalence of obesity. Over the last decade, rodent studies have yielded an impressive list of molecules associated with NAFLD and NASH pathogenesis. However, the identification of currently unknown metabolic factors using mammalian model organisms is inefficient and expensive compared with studies using fish models such as zebrafish (Danio rerio) and medaka (Oryzias latipes). Substantial advances in unraveling the molecular pathogenesis of NAFLD have recently been achieved through unbiased forward genetic screens using small fish models. Furthermore, these easily manipulated organisms have been used to great advantage to evaluate the therapeutic effectiveness of various chemical compounds for the treatment of NAFLD. In this Review, we summarize aspects of NAFLD (specifically focusing on NASH) pathogenesis that have been previously revealed by rodent models, and discuss how small fish are increasingly being used to uncover factors that contribute to normal hepatic lipid metabolism. We describe the various types of fish models in use for this purpose, including those generated by mutation, transgenesis, or dietary or chemical treatment, and contrast them with rodent models. The use of small fish in identifying novel potential therapeutic agents for the treatment of NAFLD and NASH is also addressed.

Lycopene supplementation modulates plasma concentrations and epididymal adipose tissue mRNA of leptin, resistin and IL-6 in diet-induced obese rats

Obesity is characterised by chronic low-grade inflammation, and lycopene has been reported to display anti-inflammatory effects. However, it is not clear whether lycopene supplementation modulates adipokine levels in vivo in obesity. To determine whether lycopene supplementation can regulate adipokine expression in obesity, male Wistar rats were randomly assigned to receive a control diet (C, n 6) ora hyperenergetic diet (DIO, n 12) for 6 weeks. After this period, the DIO animals were randomised into two groups: DIO (n 6) and DIO supplemented with lycopene (DIO + L, n 6). The animals received maize oil (C and DIO) or lycopene (DIO + L, 10 mg/kg body weight(BW) per d) by oral administration for a 6-week period. The animals were then killed by decapitation, and blood samples and epididymal adipose tissue were collected for hormonal determination and gene expression evaluation (IL-6, monocyte chemoattractant protein-1(MCP-1), TNF-α, leptin and resistin). There was no detectable lycopene in the plasma of the C and DIO groups. However, the mean lycopene plasma concentration was 24 nmol in the DIO + L group. Although lycopene supplementation did not affect BW or adiposity, it significantly decreased leptin, resistin and IL-6 gene expression in epididymal adipose tissue and plasma concentrations. Also, it significantly reduced the gene expression of MCP-1 in epididymal adipose tissue. Lycopene affects adipokines by reducing leptin, resistin and plasma IL-6 levels. These data suggest that lycopene may be an effective strategy in reducing inflammation in obesity.

Evaluating the effect of lycopene from Lycopersicum esculentum on apoptosis during NDEA induced hepatocarcinogenesis

The present study was aimed to examine the influence of lycopene from tomatoes (LycT) on apoptosis in N-nitrosodiethylamine (NDEA) induced hepatocarcinogenesis. Female Balb/c mice were randomly divided into four groups i.e. Control, NDEA, LycT and LycT+NDEA. Hepatic tissue from NDEA treated mice exhibited enhanced expression of anti-apoptotic gene bcl-2 and decreased expression of pro-apoptotic genes caspase 3, 9 and p53 when compared to control group. LycT intervention to NDEA challenged mice exhibited enhanced expression of caspase 3, 9 and p53 and decreased expression of bcl-2 when compared with NDEA treated animals. Enhanced DNA damage was revealed in NDEA and LycT+NDEA groups as revealed by comet assay. However, TUNEL assay indicated enhanced apoptosis in LycT+NDEA group when compared to NDEA group. Hepatic tissue of NDEA treated mice showed persistently high lipid peroxidation levels and glutathione redox ratio during the process of hepatocarcinogenesis. The observed enhanced apoptosis in LycT+NDEA group may be attributed to its differential effects on apoptosis associated genes and its ability to act as a pro-oxidant. These findings provide a rational mechanistic insight into the growth-inhibitory effects of lycopene against hepatic cancer.

Immune therapy for nonalcoholic steatohepatitis: are we there yet?

Metabolic syndrome, obesity, and nonalcoholic steatohepatitis are associated with a state of chronic inflammation. The immune system and the inflammatory cascade can be involved in the development of any of the above common conditions. This association raises the question of whether immune therapy can be used for the treatment of nonalcoholic steatohepatitis. Although immune therapy is not yet feasible for clinical use, here, we review some of the recent data on the potential role of the various arms of the immune system in the development of nonalcoholic steatohepatitis and several potential therapeutic targets.

Protective effect of lycopene against ochratoxin A induced renal oxidative stress and apoptosis in rats

This study was designed to investigate the possible protective effect of lycopene against the renal toxic effects of OTA. Male Sprague-Dawley rats (<200 g, n=6) were treated with OTA (0.5 mg/kg/day) and/or lycopene (5 mg/kg/day) by gavage for 14 days. Histopathological examinations were performed and apoptotic cell death in both cortex and medulla was evaluated by TUNEL assay. Besides, biochemical parameters and activities of renal antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD); concentrations of total glutathione (GSH), and malondialdehyde (MDA) levels were measured. OTA treatment was found to induce oxidative stress in rat kidney, as evidenced by marked decreases in CAT (35%) activity and GSH levels (44%) as well as increase in SOD activity (22%) vs control group. Furthermore, TUNEL analysis revealed a significant increase in the number of TUNEL-positive cells in cortex (49%) and medulla (75%) in OTA administrated group compared to control (p<0.05). Lycopene supplementation with OTA increased GPx1 activity and GSH levels, and decreased apoptotic cell death in both cortex and medulla vs. control. The results of this study showed that at least one of the mechanisms underlying the renal toxicity of OTA is oxidative stress and apoptosis is the major form of cell death caused by OTA. Besides, our data indicate that the natural antioxidant lycopene might be partially protective against OTA-induced nephrotoxicity and oxidative stress in rat.

The role of cytochrome P450 2E1 in ethanol-mediated carcinogenesis

We and others have shown that chronic alcohol consumption results in the induction of CYP2E1 in the liver. We have also detected for the first time such an induction in the mucosa of the small intestine and the colon. The overall induction of CYP2E1 shows interindividual variations and occurs already following a daily ingestion of 40 g of ethanol after 1 week. CYP2E1 induction is associated with an increased metabolism of ethanol resulting in the generation of reactive oxygen species (ROS) with direct and indirect carcinogenic action. ROS generated by CYP2E1 may lead to lipid peroxidation and lipid peroxidation products such as 4-hydroxynonenal bind to DNA forming highly carcinogenic exocyclic etheno DNA-adducts. The generation of these adducts has been shown in cell cultures in animal experiments as well as in human liver biopsies. CYP2E1 also metabolizes various procarcinogens present in diets and in tobacco smoke to their carcinogenic metabolites. Among these, nitrosamines seem to be the most important carcinogens. CYP2E1 also degrades retinoic acid and retinol to polar metabolites. Metabolism of retinoic acid not only results in the loss of retinoic acid promoting carcinogenesis through an increase in cell proliferation and dedifferentiation but also in generation of polar metabolites with apoptotic properties. We have shown that chlormethiazole is a specific CYP2E1 inhibitor in humans. Chlormethiazole inhibits CYP2E1 activity and thus blocks the formation of DNA adducts in cell cultures, restores retinoic acids in alcohol fed animals and inhibits chemical induced ethanol mediated hepatocarcinogenesis. Thus, there is increasing evidence that CYP2E1 induced by chronic alcohol consumption plays an important role in alcohol mediated carcinogenesis.

Lycopene counteracts the hepatic response to 7,12-dimethylbenz[a]anthracene by altering the expression of Bax, Bcl-2, caspases, and oxidative stress biomarkers

CONTEXT

Lycopene is a carotenoid found in tomato, watermelon, pink grapefruit, and guava in high concentration. Dietary intake of lycopene has been proposed to inversely correlate with the risk of cancer. It has also been reported to provide protection against cellular damage caused by reactive oxygen species, which makes it worthwhile to study the effect of lycopene on liver damage in rat model.

OBJECTIVE

In this study, we report the effect of lycopene on 7,12-dimethylbenz[a]-anthracene (DMBA)-induced expression of Bax, Bcl-2, caspases, and oxidative stres biomarkers in the liver.

MATERIALS AND METHODS

Lycopene was administered orally at 20 mg/kg body weight for 20 weeks followed by the intraperitoneal injection of DMBA (50 mg/kg body weight) on day 1 and day 30 of the experiment. Control rats received vehicle (olive oil) or DMBA alone. Rats were sacrificed after completion of the treatment.

RESULTS

We observed that the levels of Bax, caspase-3, and caspase-9 decreased to 44, 67, and 43%, respectively, and Bcl-2 increased by 80% in DMBA-treated rats. Lycopene reversed the changes in the respective groups, and decreased the level of Bcl-2 to 25%, while increasing the Bax to 42% when compared to DMBA control. Lycopene increased the expression of caspase-3 (82.09%) and caspase-9 (58.96%), and attenuated the level of hepatic malondialdehyde (41%) and 8-isoprostane (40%) when compared to the respective controls. Glutathione (GSH) decreased significantly in DMBA group (15.89%), but reached the normal level in lycopene-treated animals. Hepatic lycopene concentration in treated rats was 8.2 nmol/g tissue.

CONCLUSION

The study reports that lycopene counteracts the hepatic response to DMBA by altering the expression of Bax, Bcl-2, caspases, and oxidative stress biomarkers in animal model.

Antioxidant and antigenotoxic effects of lycopene in obstructive jaundice

BACKGROUND

Obstructive jaundice, a frequently observed condition caused by obstruction of the common bile duct or its flow and seen in many clinical situations, may end up with serious complications like sepsis, immune depression, coagulopathy, wound breakdown, gastrointestinal hemorrhage, and hepatic and renal failures. Intrahepatic accumulation of reactive oxygen species is thought to be an important cause for the possible mechanisms of the pathogenesis of cholestatic tissue injury from jaundice. Carotenoids have been well described that are able to scavenge reactive oxygen species. Lycopene, a carotenoid present in tomatoes, tomato products, and several fruits and vegetables, have been suggested to have antioxidant activity, so may play a role in certain diseases related to the oxidative stress. The aim of the present study was to determine the effects of lycopene on oxidative stress and DNA damage induced by experimental biliary obstruction in Wistar albino rats.

MATERIALS AND METHODS

Daily doses of 100 mg/kg lycopene were given to the bile duct-ligation (BDL) rats orally for 14 days. DNA damage was evaluated by an alkaline comet assay. The levels of aspartate transferase, amino alanine transferase, gamma glutamyl transferase, alkaline phosphatase, and direct bilirubin were analyzed in plasma for the determination of liver functions. The levels of malondialdehyde, reduced glutathione, nitric oxide, catalase, superoxide dismutase, and glutathione S transferase were determined in the liver and kidney tissues. Pro-inflammatory cytokine tumor necrosis factor-alpha level was determined in the liver tissues. Histologic examinations of the liver and kidney tissues were also performed.

RESULTS

According to this study, lycopene significantly recovered the parameters of liver functions in plasma, reduced malondialdehyde and nitric oxide levels, enhanced reduced glutathione levels, as well as enhancing all antioxidant enzyme activity in all tissues obtained from the BDL group. Moreover, the parameters of DNA damage in the liver and kidney tissue cells, whole blood cells, and lymphocytes were significantly lower in the lycopene-treated BDL group, compared with the BDL group.

CONCLUSIONS

Lycopene significantly reduced the DNA damage, and markedly recovered the liver and kidney tissue injuries seen in rats with obstructive jaundice.

Lycopene metabolism and its biological significance

The beneficial effects of a high intake of tomatoes and tomato products on the risk of certain chronic diseases have been presented in many epidemiologic studies, with the suggestion that lycopene (a major carotenoid in tomatoes) is a micronutrient with important health benefits. Within the past few years, we have gained greater knowledge of the metabolism of lycopene and the biological effects of lycopene derivatives. In particular, the characterization and study of β-carotene 9',10'-oxygenase has shown that this enzyme can catalyze the excentric cleavage of both provitamin and non-provitamin A carotenoids to form apo-10'-carotenoids, including apo-10'-lycopenoids from lycopene. This raised an important question of whether the effect of lycopene on various cellular functions and signaling pathways is a result of the direct actions of intact lycopene or its derivatives. Several reports, including our own, support the notion that the biological activities of lycopene can be mediated by apo-10'-lycopenoids. More research is clearly needed to identify and characterize additional lycopene metabolites and their biological activities, which will potentially provide invaluable insights into the mechanisms underlying the effects of lycopene in humans.

Tomato juice consumption reduces systemic inflammation in overweight and obese females

Tomatoes are the richest source of lycopene, a potent antioxidant. Tomato products improve antioxidant defences and reduce the risk of inflammatory diseases, at least partly, due to the presence of lycopene. Lycopene, as an anti-inflammatory agent, prevents the production of inflammatory cytokines. Obesity is a chronic inflammatory condition in which the increased level of body fat leads to an increase in circulating inflammatory mediators. We hypothesised that the consumption of a lycopene-rich food would reduce inflammation in people who are overweight or obese. A total of 106 overweight or obese female students of the Tehran University of Medical Sciences were enrolled and randomly allocated to an intervention group (n 53) or a control group (n 53) consuming 330 ml/d of tomato juice or water, respectively, for 20 d. At baseline and day 20, serum concentrations of IL-6, IL-8, high-sensitivity C-reactive protein and TNF-α were analysed by ELISA and compared between the groups. Serum concentrations of IL-8 and TNF-α decreased significantly in the intervention group compared with the control group and with baseline. Subgroup analysis indicated that this effect was confined to subjects who were overweight. Among obese subjects, serum IL-6 concentration was decreased in the intervention group compared with the control group, with no differences in IL-8 and TNF-α observed. Tomato juice reduces inflammation in overweight and obese females. Thus, increasing tomato intake may provide a useful approach for reducing the risk of inflammatory diseases such as CVD and diabetes, which are associated with obesity.

Lycopene inhibits hepatic steatosis via microRNA-21-induced downregulation of fatty acid-binding protein 7 in mice fed a high-fat diet

SCOPE

Nonalcoholic fatty liver disease (NAFLD) is a chronic disorder characterized by hepatic fat accumulation and abnormal lipid metabolism. Here, we investigated the protective effect of lycopene on high-fat diet-induced hepatic steatosis and fatty acid-induced intracellular lipid accumulation by miRNA regulation.

METHODS AND RESULTS

C57BL/6J mice were fed high-fat diet with or without 0.05% lycopene for 8 weeks. Hepa 1-6 cells were treated with stearic acid (SA) after 24 h pretreatment with lycopene. Treatment of lycopene improved hepatic steatosis in high-fat-fed mice and reduced intracellular lipid accumulation induced by SA in Hepa 1-6 cells. We demonstrated that miR-21 expression was decreased in livers from high-fat diet-fed mice and Hepa 1-6 cells treated with SA. Lycopene normalized the downregulation of miR-21, which led to the downregulation of fatty acid-binding protein 7 (FABP7), a direct target of miR-21, at both the transcriptional and translational levels. This specific negative regulation of miR-21 was achieved by targeting the FABP7 3'UTR. Upregulation of miR-21 markedly blocked SA-induced intracellular lipid accumulation by blocking FABP7 expression. Moreover, silencing of FABP7 reduced SA-evoked lipid accumulation in Hepa 1-6 cells.

CONCLUSION

The results suggest that lycopene may be a useful functional compound for treating NAFLD by regulating hepatic lipid metabolism.

Spectroscopic characterization of lycopene extract from Lycopersicum esculentum (Tomato) and its evaluation as a chemopreventive agent against experimental hepatocarcinogenesis in mice

The present study was designed to characterize the lycopene extract (LycT) prepared from tomatoes (Lycopersicum esculentum) and then to evaluate its chemopreventive efficacy in N-diethylnitrosamine (NDEA)-induced experimental hepatocarcinogenesis in female Balb/c mice. The extraction of lycopene was carried out using hexane/acetone/ethanol as an extracting medium and then characterized by ultraviolet-visible, nuclear magnetic resonance and Fourier transform infrared spectroscopy. Chemopreventive efficacy of characterized LycT in vivo was evaluated in terms of hepatic tumour incidence, multiplicity, burden, hepatosomatic index and animal survival rate. Results indicated that average lycopene content of the tomato was 11.6-14 mg/kg tomato weight. Spectroscopic data confirmed the structural characteristics of lycopene in the extract. In the animal study, reduction in tumour incidence (42.05%), tumour burden (1.39) and tumour multiplicity (3.42) was observed upon LycT pretreatment to NDEA-treated animals. Histopathological analysis unravelled that the increased survival rate in LycT + NDEA-treated animals was due to the delay in the formation of aggressive tumour nodules. These observations indicate that lycopene seems to be an able candidate for chemoprevention in hepatocarcinogenesis resulting from NDEA insults.

Apo-10'-lycopenoic acid, a lycopene metabolite, increases sirtuin 1 mRNA and protein levels and decreases hepatic fat accumulation in ob/ob mice

Lycopene has been shown to be beneficial in protecting against high-fat diet-induced fatty liver. The recent demonstration that lycopene can be converted by carotene 9',10'-oxygenase into a biologically active metabolite, ALA, led us to propose that the function of lycopene can be mediated by ALA. In the present study, male ob/ob mice were fed a liquid high-fat diet (60% energy from fat) with ALA supplementation (ALA group, 240 μg · kg body weight(-1) · d(-1)) or without ALA supplementation as the control (C group) for 16 wk. Steatosis, SIRT1 expression and activity, genes involved in lipid metabolism, and ALA concentrations in the livers of mice were examined. The results showed that ALA supplementation resulted in a significant accumulation of ALA in the liver and markedly decreased the steatosis in the ALA group without altering body and liver weights compared to the C group. The mRNA and protein levels of hepatic SIRT1 were higher in the ALA group compared to the C group. SIRT1 activity also was higher in the ALA group, as indicated by the lower levels of acetylated forkhead box class O1 protein levels. In addition, the mRNA level of acetyl CoA carboxylase 1 was significantly lower in the ALA group than in the C group. Because SIRT1 plays a key role in lipid homeostasis, the present study suggests that the lycopene metabolite, ALA, protects against the development of steatosis in ob/ob mice by upregulating SIRT1 gene expression and activity.

Lycopene inhibits caspase-3 activity and reduces oxidative organ damage in a rat model of thermal injury

Oxidative stress has been implicated in various pathological processes including burn induced multiple organ damage. This study investigated the effects of lycopene treatment against oxidative injury in rats with thermal trauma. Under ether anesthesia, shaved dorsum of the rats was exposed to 90°C bath for 10s to induce burn and treated either vehicle (olive oil) or lycopene (50mg/kg orally). Rats were decapitated 48 h after injury and the tissue samples from lung and kidney were taken for histological analysis and the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and caspase-3 activities. Proinflammatory cytokines, TNF-α and IL-1β, were assayed in blood samples. Severe skin scald injury caused a significant decrease in GSH levels, SOD and CAT activities, and significant increases in MDA levels, MPO and caspase-3 activities of tissues. Similarly, plasma TNF-α and IL-1β were elevated in the burn group as compared to the control group. Lycopene treatment reversed all these biochemical indices. According to the findings of the present study, lycopene possesses antiinflammatory, antiapoptotic and antioxidant effects that prevents burn-induced oxidative damage in remote organs.

Mammalian carotenoid-oxygenases: key players for carotenoid function and homeostasis

Humans depend on a dietary intake of lipids to maintain optimal health. Among various classes of dietary lipids, the physiological importance of carotenoids is still controversially discussed. On one hand, it is well established that carotenoids, such as β,β-carotene, are a major source for vitamin A that plays critical roles for vision and many aspects of cell physiology. On the other hand, large clinical trials have failed to show clear health benefits of carotenoids supplementation and even suggest adverse health effects in individuals at risk of disease. In recent years, key molecular players for carotenoid metabolism have been identified, including an evolutionarily well conserved family of carotenoid-oxygenases. Studies in knockout mouse models for these enzymes revealed that carotenoid metabolism is a highly regulated process and that this regulation already takes place at the level of intestinal absorption. These studies also provided evidence that β,β-carotene conversion can influence retinoid-dependent processes in the mouse embryo and in adult tissues. Moreover, these analyses provide an explanation for adverse health effects of carotenoids by showing that a pathological accumulation of these compounds can induce oxidative stress in mitochondria and cell signaling pathways related to disease. Advancing knowledge about carotenoid metabolism will contribute to a better understanding of the biochemical and physiological roles of these important micronutrients in health and disease. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.

Transcriptome analysis of anti-fatty liver action by Campari tomato using a zebrafish diet-induced obesity model

BACKGROUND

High dietary intake of vegetable products is beneficial against obesity and its related diseases such as dyslipidemia, nonalcoholic fatty liver disease, and cancer. We previously developed a diet-induced obesity model of zebrafish (DIO-zebrafish) that develops visceral adiposity, dyslipidemia, and liver steatosis. Zebrafish is a polyphagous animal; thus we hypothesized that DIO-zebrafish could be used for transcriptome analysis of anti-obesity effects of vegetables.

RESULTS

Each vegetable exhibited different effects against obesity. We focused on "Campari" tomato, which suppressed increase of body weight, plasma TG, and lipid droplets in livers of DIO-zebrafish. Campari tomato decreased srebf1 mRNA by increase of foxo1 gene expression, which may depend on high contents of β-carotene in this strain.

CONCLUSIONS

Campari tomato ameliorates diet-induced obesity, especially dyslipidemia and liver steatosis via downregulation of gene expression related to lipogenesis. DIO-zebrafish can discriminate the anti-obesity effects of different strains of vegetables, and will become a powerful tool to assess outcomes and find novel mechanisms of anti-obesity effects of natural products.

Inhibitory effects of combination of lycopene and genistein on 7,12- dimethyl benz(a)anthracene-induced breast cancer in rats

Breast cancer is one of the most common cancers in women. Carotenoids and soy isoflavones have been postulated to have breast cancer preventive effects. We investigated the potential preventive effects of lycopene and genistein, alone and in combination, on breast cancer development in female Wistar rats treated with 7,12-dimethylbenz[a]anthracene (DMBA), a carcinogen known to induce breast tumors. Mammary carcinogenesis was initiated by a single, oral gavage of DMBA (80 mg/kg body weight) at 55 days of animal age. Fifty female Wistar rats were divided into 5 experimental groups having 10 animals per group: Group 1 (normal control), Group 2 (DMBA control), Group 3 (DMBA + lycopene), Group 4 (DMBA + genistein), and Group 5 (DMBA + lycopene and genistein). Rats were fed either lycopene (20 mg /kg bw) or genistein (2 mg /kg bw) by oral gavage (3 times per week) starting 2 wk prior to DMBA injection. Treatment was continued for 20 wk. Rats treated with DMBA developed mammary tumors with 100% tumor incidence during the 20-wk study. Inhibition of mammary cancer incidence by lycopene (70%), genistein (60%) and their combination (40%) was observed. Tumor weight decreased by 48%, 61%, and 67%, and mean tumor volume decreased by 18%, 35%, and 65% with lycopene, genistein, and lycopene + genistein, respectively (P < 0.01 for the combination). The proportions of adenocarcinoma masses decreased with lycopene and genistein combination (P < 0.05). Administration of lycopene and genistein combination suppressed breast cancer development and was associated with a decrease in MDA, 8-isoprostane, and 8-OhdG levels and with an increase in serum lycopene and genistein levels. Animals administered DMBA developed breast cancer, which was associated with increased expression of Bcl-2 and decreased expression of Bax, caspase 3, and caspase 9 in mammary tissues. Administration of genistein and lycopene in combination was more effective in inhibiting DMBA-induced breast tumors and modulating the expression of apoptosis associated proteins than the administration of each agent alone. Our results suggest that lycopene and genistein are potent antioxidants and, when given in combination, offer maximum protection against DMBA-induced mammary carcinogenesis.

Terpenoids as potential chemopreventive and therapeutic agents in liver cancer

Despite significant advances in medicine, liver cancer, predominantly hepatocellular carcinoma remains a major cause of death in the United States as well as the rest of the world. As limited treatment options are currently available to patients with liver cancer, novel preventive control and effective therapeutic approaches are considered to be reasonable and decisive measures to combat this disease. Several naturally occurring dietary and non-dietary phytochemicals have shown enormous potential in the prevention and treatment of several cancers, especially those of the gastrointestinal tract. Terpenoids, the largest group of phytochemicals, traditionally used for medicinal purposes in India and China, are currently being explored as anticancer agents in clinical trials. Terpenoids (also called "isoprenoids") are secondary metabolites occurring in most organisms, particularly plants. More than 40 000 individual terpenoids are known to exist in nature with new compounds being discovered every year. A large number of terpenoids exhibit cytotoxicity against a variety of tumor cells and cancer preventive as well as anticancer efficacy in preclinical animal models. This review critically examines the potential role of naturally occurring terpenoids, from diverse origins, in the chemoprevention and treatment of liver tumors. Both in vitro and in vivo effects of these agents and related cellular and molecular mechanisms are highlighted. Potential challenges and future directions involved in the advancement of these promising natural compounds in the chemoprevention and therapy of human liver cancer are also discussed.