Preventive role of genistein in an experimental non-alcoholic steatohepatitis model

Therapeutic potential of traditional Chinese medicine in the prevention and treatment of digestive inflammatory cancer transformation: Portulaca oleracea L. as a promising drug

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) has been used for centuries to treat various types of inflammation and tumors of the digestive system. Portulaca oleracea L. (POL), has been used in TCM for thousands of years. The chemical composition of POL is variable and includes flavonoids, alkaloids, terpenoids and organic acids and other classes of natural compounds. Many of these compounds exhibit powerful anti-inflammatory and anti-cancer-transforming effects in the digestive system.

AIM OF STUDY

In this review, we focus on the potential therapeutic role of POL in NASH, gastritis and colitis and their associated cancers, with a focus on the pharmacological properties and potential mechanisms of action of the main natural active compounds in POL.

METHODS

The information and data on Portulaca oleracea L. and its main active ingredients were collated from various resources like ethnobotanical textbooks and literature databases such as CNKI, VIP (Chinese literature), PubMed, Science Direct, Elsevier and Google Scholar (English literatures), Wiley, Springer, Tailor and Francis, Scopus, Inflibnet.

RESULTS

Kaempferol, luteolin, myricetin, quercetin, genistein, EPA, DHA, and melatonin were found to improve NASH and NASH-HCC, while kaempferol, apigenin, luteolin, and quercetin played a therapeutic role in gastritis and gastric cancer. Apigenin, luteolin, myricetin, quercetin, genistein, lupeol, vitamin C and melatonin were found to have therapeutic effects in the treatment of colitis and its associated cancers. The discovery of the beneficial effects of these natural active compounds in POL supports the idea that POL could be a promising novel candidate for the treatment and prevention of inflammation-related cancers of the digestive system.

CONCLUSION

The discovery of the beneficial effects of these natural active compounds in POL supports the idea that POL could be a promising novel candidate for the treatment and prevention of inflammation-related cancers of the digestive system. However, clinical data describing the mode of action of the naturally active compounds of POL are still lacking. In addition, pharmacokinetic data for POL compounds, such as changes in drug dose and absorption rates, cannot be extrapolated from animal models and need to be measured in patients in clinical trials. On the one hand, a systematic meta-analysis of the existing publications on TCM containing POL still needs to be carried out. On the other hand, studies on the hepatic and renal toxicity of POL are also needed. Additionally, well-designed preclinical and clinical studies to validate the therapeutic effects of TCM need to be performed, thus hopefully providing a basis for the validation of the clinical benefits of POL.

The effect of soy isoflavones on non-alcoholic fatty liver disease and the level of fibroblast growth factor-21 and fetuin A

A two-arm randomized open labeled controlled clinical trial was conducted on 50 patients with non-alcoholic fatty liver disease (NAFLD). Subjects were randomized to either receive two tablets of soy isoflavone (100 mg/day) or placebo. At week 12, the serum levels of alanine amino transferase (ALT), aspartate amino transferase (AST) and controlled attenuation parameter (CAP) score were significantly decreased only in the soy isoflavone group (P < 0.05). A significant decline in the gamma glutamyl transferase (GGT) level was observed only in the placebo group (P = 0.017). A significant increase in the serum level of fetuin A was shown in both groups at the end of the trial with a significantly greater increment in the soy isoflavone group compared to the placebo group (P < 0.05). The changes in the serum level of FGF-21 were not significant in any of the two groups. Steatosis grade significantly improved only in the soy isoflavone group (P = 0.045). There was no significant change in the fibrosis grade in the groups. Soy isoflavone intake led to a decrease in ALT, AST, CAP score, steatosis grade and an increase in the level of fetuin A. However, no significant changes were observed in the fibrosis grade and serum levels of GGT and FGF-21.

Protective effect of phytoestrogens on nonalcoholic fatty liver disease in postmenopausal women

Non-alcoholic fatty liver disease (NAFLD) is a progressive metabolic disease characterized by hepatic steatosis, inflammation, and fibrosis that seriously endangers global public health. Epidemiological studies have shown that the incidence of non-alcoholic fatty liver disease in postmenopausal women has significantly increased. Studies have shown that estrogen deficiency is the main reason for this situation, and supplementing estrogen has become a new direction for preventing the occurrence of postmenopausal fatty liver. However, although classical estrogen replacement therapy can reduce the incidence of postmenopausal NAFLD, it has the risk of increasing stroke and cardiovascular diseases, so it is not suitable for the treatment of postmenopausal NAFLD. More and more recent studies have provided evidence that phytoestrogens are a promising method for the treatment of postmenopausal NAFLD. However, the mechanism of phytoestrogens in preventing and treating postmenopausal NAFLD is still unclear. This paper summarizes the clinical and basic research evidence of phytoestrogens and reviews the potential therapeutic effects of phytoestrogens in postmenopausal NAFLD from six angles: enhancing lipid metabolism in liver and adipose tissue, enhancing glucose metabolism, reducing oxidative stress, reducing the inflammatory response, regulating intestinal flora, and blocking liver fibrosis (Graphical Abstract).

Mitigation of MAFLD in High Fat-High Sucrose-Fructose Fed Mice by a Combination of Genistein Consumption and Exercise Training

PURPOSE

Metabolic dysfunction-associated fatty liver disease (MAFLD) is fueled by escalations in both sedentary behavior and caloric intake and is noted in obese type 2 diabetic (T2DM) patients. This study aimed to examine the effects of exercise and the phytoestrogen genistein in mice fed a high fat (60% fat) high sugar (55% fructose with 45% sucrose), HFHS diet.

METHODS

Male C57BL/6J mice were assigned to five groups: HFHS, HFHS with genistein (600 mg/kg diet, HFHS+Gen), HFHS with moderate exercise (HFHS+Ex), and HFHS with combined genistein and moderate exercise (HFHS-Gen+Ex). Control lean mice were fed standard chow and water. Exercise consisted of 30-minute sessions of treadmill running five days/week for the 12-week study duration. Body weight was assessed weekly. Liver, kidney, fecal pellets and serum were extracted at the end of the study and maintained at -80°C.

RESULTS

After 12 weeks of treatment, mice in the HFHS group had the highest hepatic lipid content. Plasma levels of glucose, insulin, leptin, cholesterol, amylin, and total fat content were significantly elevated in HFHS mice compared to control mice. HFHS feeding increased protein expression of carnitine palmitoyltransferase 1b (CPT-1b isoform) in gastrocnemius, CPT1a, glucose transporter protein 2 (GLUT2), glucocorticoid receptor (GR), and fructose 1,6-bisphosphate 1 (FBP1) expression in liver. Exercise alone had minor effects on these metabolic abnormalities. Genistein alone resulted in improvements in body weight, fat content, amylin, insulin sensitivity, and liver histopathology, GR, FBP1, and acetyl-CoA carboxylase 1 (ACC1). Combination treatment resulted in additional metabolic improvements, including reductions in hepatic lipid content and lipid area, alanine transferase activity, CPT1b, and CPT1a.

CONCLUSION

Our results indicate that a HFHS diet is obesogenic, inducing metabolic perturbations consistent with T2DM and MAFLD. Genistein alone and genistein combined with moderate intensity exercise were effective in reducing MAFLD and the aberrations induced by chronic HFHS feeding.

Polyphenols: Potential anti-inflammatory agents for treatment of metabolic disorders

Ample evidence highlights the potential benefits of polyphenols in health status especially in obesity-related metabolic disorders such as insulin resistance, type 2 diabetes, and cardiovascular diseases. Mechanistically, due to the key role of "Metainflammation" in the pathomechanism of metabolic disorders, recently much focus has been placed on the properties of polyphenols in obesity-related morbidities. This narrative review summarizes the current knowledge on the role of polyphenols, including genistein, chlorogenic acid, ellagic acid, caffeic acid, and silymarin in inflammatory responses pertinent to metabolic disorders and discusses the implications of this evidence for future directions. This review provides evidence that the aforementioned polyphenols benefit health status in metabolic disorders via direct and indirect regulation of a variety of target proteins involved in inflammatory signaling pathways. However, due to limitations of the in vitro and in vivo studies and also the lack of long-term human clinical trials studies, further high-quality investigations are required to firmly establish the clinical efficacy of the polyphenols for the prevention and management of metabolic disorders.

Metformin in combination with genistein ameliorates skeletal muscle inflammation in high-fat diet fed c57BL/6 mice

Although the beneficial effects of metformin (MET) and genistein in ameliorating inflammation have been elucidated, their combined impacts on skeletal muscle inflammation have not been clearly understood. This study aimed to examine the possible preventive effect of MET in combination with genistein on skeletal muscle inflammation in high-fat diet (HFD) fed C57BL/6 mice. Fifty C57BL/6 male mice were fed on an HFD for 10 weeks. The mice were categorized into five groups, control, HFD, HFD + MET (0.23%), HFD + genistein (0.2%), and HFD + MET + genistein for 12 weeks. The results showed that treatment with MET and genistein, either alone or in combination, led to reduced weight gain, fasting blood glucose, plasma insulin, HOMA-IR levels, and Area Under the Curves (AUCs) in ipGTT. MET in combination with genistein demonstrated a decreasing effect on macrophages infiltration rate compared to genistein and MET groups alone. The expression of iNOS was reduced, whereas the expression of M2 macrophage markers was increased in combined treatment of MET and genistein. Furthermore, MET in combination with genistein reduced the expression of TNF-α, IL-1β, MCP-1, and IL-6 and increased the expression of IL-10 in comparison with genistein and MET groups alone. Plasma and skeletal muscle triglycerides and intra-myocellular lipid deposition were reversed by treatment with MET and genistein, alone or in combination. These results imply that the combination therapy of MET and genistein may have therapeutic potential for decreasing obesity-induced skeletal muscle inflammation in the HFD-fed model.

Effect of Nigella sativa, atorvastatin, or L-Carnitine on high fat diet-induced obesity in adult male Albino rats

Obesity is increasing rapidly across the globe. It is widely accepted that natural products with a long safety background may modulate obesity. The current work aimed to investigate the effect of Nigella sativa, atorvastatin, or L-Carnitine on high-fat diet-induced obesity in white male albino rats. A regular basal diet was fed to 7 rats, and a high-fat diet (HFD) was fed to 24 rats throughout the study for 12 weeks. The HFD group was split equally into four subgroups, each containing six rats. The first group fed on HFD with no medication, the second group received HFD+ Nigella sativa, the third group received HFD+ atorvastatin, and the fourth group received HFD+L-carnitine. At the beginning of the seventh week (the start of the treatment regimen), Nigella sativa, atorvastatin, or L-Carnitine were administered for six weeks. Glucose, body weight, serum atherogenic index (AI), ALT, and AST activities were analyzed. The pathological alterations in the hepatic tissues were examined microscopically and scored. The results revealed that the HFD diet significantly increased the final body weight, serum AI, and serum levels of liver enzymes. Treatment with L-carnitine or Nigella sativa significantly normalized the lipid profile and decreased the final body weight, serum AI, and Serum ALT. Histopathological examination of the liver of HFD received rats showed features of steatosis, which were mitigated by the administration of Nigella sativa or L-Carnitine, while atorvastatin had no significant effect on the improvement of hepatic lesions. Collectively, study findings showed that Nigella sativa or L-Carnitine has mitigated effects on metabolic and histopathological changes in the liver tissues of rats fed with HFD.

Influence of Genistein on Hepatic Lipid Metabolism in an In Vitro Model of Hepatic Steatosis

Nonalcoholic fatty liver disease (NAFLD) is among the leading causes of end-stage liver disease. The impaired hepatic lipid metabolism in NAFLD is exhibited by dysregulated PPARα and SREBP-1c signaling pathways, which are central transcription factors associated with lipid degradation and de novo lipogenesis. Despite the growing prevalence of this disease, current pharmacological treatment options are unsatisfactory. Genistein, a soy isoflavone, has beneficial effects on lipid metabolism and may be a candidate for NAFLD treatment. In an in vitro model of hepatic steatosis, primary human hepatocytes (PHHs) were incubated with free fatty acids (FFAs) and different doses of genistein. Lipid accumulation and the cytotoxic effects of FFAs and genistein treatment were evaluated by colorimetric and enzymatic assays. Changes in lipid homeostasis were examined by RT-qPCR and Western blot analyses. PPARα protein expression was induced in steatotic PHHs, accompanied by an increase in CPT1L and ACSL1 mRNA. Genistein treatment increased PPARα protein expression only in control PHHs, while CPTL1 and ACSL1 were unchanged and PPARα mRNA was reduced. In steatotic PHHs, genistein reversed the increase in activated SREBP-1c protein. The model realistically reflected the molecular changes in hepatic steatosis. Genistein suppressed the activation of SREBP-1c in steatotic hepatocytes, but the genistein-mediated effects on PPARα were abolished by high hepatic lipid levels.

Natural Aldose Reductase Inhibitor: A Potential Therapeutic Agent for Non-alcoholic Fatty Liver Disease

Aldose reductase (AR) has been reported to be involved in the development of nonalcoholic fatty liver disease (NAFLD). Hepatic AR is induced under hyperglycemia condition and converts excess glucose to lipogenic fructose, which contributes in part to the accumulation of fat in the liver cells of diabetes rodents. In addition, the hyperglycemia-induced AR or nutrition-induced AR causes suppression of the transcriptional activity of peroxisome proliferator-activated receptor (PPAR) α and reduced lipolysis in the liver, which also contribute to the development of NAFLD. Moreover, AR induction in non-alcoholic steatohepatitis (NASH) may aggravate oxidative stress and the expression of inflammatory cytokines in the liver. Here, we summarize the knowledge on AR inhibitors of plant origin and review the effect of some plant-derived AR inhibitors on NAFLD/NASH in rodents. Natural AR inhibitors may improve NAFLD at least in part through attenuating oxidative stress and inflammatory cytokine expression. Some of the natural AR inhibitors have been reported to attenuate hepatic steatosis through the regulation of PPARα-mediated fatty acid oxidation. In this review, we propose that the natural AR inhibitors are potential therapeutic agents for NAFLD.

New insight and potential therapy for NAFLD: CYP2E1 and flavonoids

Over the years, the prevalence of nonalcoholic fatty liver disease (NAFLD) has increased year by year; however, due to its complicated pathogenesis, there is no effective treatment so far. It is reported that Cytochrome P450 2E1 (CYP2E1) plays an indispensable role in the development of NAFLD, and numerous studies have shown that flavonoids have a hepatoprotective effect and can exert a beneficial effect on NAFLD by regulating the activity of CYP2E1. Therefore, flavonoids may become effective drugs for the treatment of NAFLD in the future. This prompted us to review the research progress of the pathological mechanism of NAFLD and the impact of CYP2E1 activity changes during the pathological process, and to summarize the protective effect of flavonoids against CYP2E1 activity.

Protection of Fatty Liver by the Intake of Fermented Soybean Paste, Miso, and Its Pre-Fermented Mixture

Soybeans and fermented soy-derived foodstuffs contain many functional components and demonstrate various beneficial effects. In this report, we demonstrate the anti-fatty liver effect of miso, a traditional fermented product made from soybeans and rice molded in Aspergillus oryzae and forming a common part of the Japanese diet. After acclimation for 2 weeks, male and female C57BL/6J mice were fed with a normal diet (ND), a high-fat diet (HFD), a HFD containing 5% miso (HFD+M), or a HFD containing 5% pre-fermented miso (HFD+PFM) for 20 weeks. Although mice in the HFD group developed typical fatty liver, the consumption of miso or PFM significantly ameliorated the progression of fatty liver in female mice. The liver weight and the average nonalcoholic fatty liver disease activity score (NAS) were significantly reduced in the HFD+M and HFD+PFM groups. In addition, leptin and resistin levels in the serum were decreased in the HFD+M and HFD+PFM groups. The progression of fatty liver was also prevented by the consumption of miso or PFM in male mice, although there were no decreases in NAS. Therefore, miso appears to be a potential food to prevent lifestyle-related diseases such as metabolic syndrome.

Interaction of Polyphenols as Antioxidant and Anti-Inflammatory Compounds in Brain-Liver-Gut Axis

Oxidative stress plays an important role in the onset as well as the progression of inflammation. Without proper intervention, acute inflammation could progress to chronic inflammation, resulting in the development of inflammatory diseases. Antioxidants, such as polyphenols, have been known to possess anti-oxidative properties which promote redox homeostasis. This has encouraged research on polyphenols as potential therapeutics for inflammation through anti-oxidative and anti-inflammatory pathways. In this review, the ability of polyphenols to modulate the activation of major pathways of inflammation and oxidative stress, and their potential to regulate the activity of immune cells are examined. In addition, in this review, special emphasis has been placed on the effects of polyphenols on inflammation in the brain–liver–gut axis. The data derived from in vitro cell studies, animal models and human intervention studies are discussed.

Protective effect of genistein on nonalcoholic fatty liver disease (NAFLD)

NAFLD is a vital health problem worldwide; however, no effective treatment is currently available for NAFLD. Intensive studies have indicated the efficacy of genistein (GE), a bioactive isoflavone extracted from soy, in treating NAFLD. In addition to its oestrogen-like effects, GE is known to have multiple molecular effects, for instance, lipid and glucose metabolism-promoting effects and activities against lipid peroxidation, inflammation, fibrosis, and NAFLD-related tumours. Here, this review summarizes the potential role of GE in the treatment and prevention of NAFLD and some of the currently known targets and signalling pathways of GE in NAFLD.

l-Carnitine-induced amelioration of HFD-induced hepatic dysfunction is accompanied by a reduction in hepatic TNF-α and TGF-β1

In this study, we evaluated the possible mechanisms through which l-carnitine ameliorates the adverse effects from obesity in rats, induced with a high-fat diet (HFD). For this, 56 albino Wister rats were randomly assigned to 7 groups. The control group was fed a basal diet and injected with saline. The second group was fed the basal diet and injected with l-carnitine (200 mg/kg body mass, by intraperitoneal injection; i.p.). The third group were fed the HFD. The fourth group was fed the HFD and injected with l-carnitine (200 mg/kg body mass, i.p.) for 8 weeks. The fifth group was fed the HFD for 10 weeks. The sixth group were fed the HFD for 10 weeks and were also injected with l-carnitine (200 mg/kg body mass, i.p.) during the final 2 weeks. The seventh group was fed the HFD diet for 8 weeks then the basal diet for 2 weeks. The HFD induced significantly increased levels of hyperglycemia, lipid peroxidation, pathological changes, TNF-α and TGF-β1 protein expression in hepatic tissue, food intake, body weight gain, serum levels of total and non-high-density lipoprotein cholesterol, ketone bodies, triacylglycerol, urea, creatinine, AST, and ALT. However, the HFD diet significantly decreased serum levels of high-density lipoprotein (HDL) and hepatic levels of reduced glutathione. l-Carnitine ameliorated the effects of the HFD on the above-mentioned parameters. This study indicated that l-carnitine had protective and curative effects against HFD-induced hepatosteatosis by reducing hepatic oxidative stress and protein expression of TNF-α and TGF-β1.

The relationship between urinary genistein levels and serum alanine aminotransferase levels in adults in the USA: National Health and Nutrition Examination Survey 1999-2010

BACKGROUND

Genistein, a phytoestrogen with similarities to female sex hormones, has been shown to protect against oxidative stress and fibrosis in nonalcoholic fatty liver injury in animal studies. However, few studies have examined genistein's effects on liver function in humans.

PARTICIPANTS AND METHODS

We analyzed data from the National Health and Nutrition Examination Survey from 1999 to 2010. Individuals younger than 21 years, with viral hepatitis, or with serum alanine aminotransferase (ALT) at the extremes of distribution (5% on each extreme) were excluded. Urinary genistein was normalized by urinary creatinine levels. The relationship between normalized urinary genistein (nUG) and serum ALT was examined using linear regression models with and without adjustment for potential confounders, and the differential effect of sex was examined using an interaction term.

RESULTS

Of the 9864 participants, 52% were female, 50% were White, 24% were elderly, 36% had hypertension, 12% had diabetes, and 8.1% were heavy alcohol drinkers. Serum ALT was significantly lower in the highest quartile compared with the lowest quartile of nUG (22.3 vs. 23.5 U/l; P<0.001). In adjusted models, individuals in the highest quartile had 0.75 U/l lower ALT levels than those in the lowest quartile (P=0.02). We found a significant difference in ALT levels between the lowest and highest quartiles of nUG in males, but not in females (difference in differences=1.77 U/l, interaction P=0.04).

CONCLUSION

We found a statistically significant association between higher nUG and lower serum ALT in males, but not in females. The sex-specific role of genistein in mitigating liver disease merits further study.

Genistein Ameliorates Cyclophosphamide - Induced Hepatotoxicity by Modulation of Oxidative Stress and Inflammatory Mediators

AIM:

The present study investigated the protective effect of the phytoestrogen, genistein (GEN), against (CP)-induced acute hepatotoxicity in rats.

MATERIAL AND METHODS:

Male adult rats were randomly assigned into five groups. Normal control group received the vehicles; CP group received a single dose of CP (200 mg/kg, i.p). The other three groups received subcutaneous GEN at doses of 0.5, 1 and 2 mg/kg/day, respectively, for 15 consecutive days prior CP injection. Sera and liver tissues were collected forty-eight hours after CP injection for assessment of liver function enzymes (ALT and AST) in rat sera, the hepatic oxidative/nitrosative biomarkers (GSH, MDA and NOx), hepatic interleukin-1β, and myeloperoxidase activity. Immunohistochemistry of cyclooxygenase-2 and histopathological examination of liver tissues were also conducted.

RESULTS:

The CP-induced acute liver damage was evidenced by elevated serum ALT and AST accompanied by increased hepatic oxidative stress and inflammatory biomarkers. Immunohistochemical outcomes revealed hepatic cyclooxygenase-2 expression in CP group with distortion of liver architecture. GEN-pretreatment significantly ameliorated the deterioration of liver function and exerted significant anti-oxidant and anti-inflammatory activity with a marked decline in hepatic cyclooxygenase-2 expression in a dose dependent-manner.

CONCLUSION:

The present study demonstrated that the antioxidant and anti-inflammatory activities of GEN might contribute to its protective effects against CP-induced liver damage.

Genistein supplementation improves insulin resistance and inflammatory state in non-alcoholic fatty liver patients: A randomized, controlled trial

BACKGROUND & AIMS

The beneficial effect of genistein has indicated on metabolic disorders and inflammatory state. The aim of this study was to investigate the effect of genistein supplementation on non-alcoholic fatty liver disease (NAFLD) as the hepatic manifest of metabolic syndrome.

METHODS

In the present randomized double-blind controlled trial, patients with NAFLD were daily supplemented with either 250 mg genistein (n = 41) or placebo (n = 41) for 8-weeks. Both groups were instructed to follow an energy-balanced diet and physical activity recommendations. And their anthropometric and biochemical indices were assessed before and after the intervention.

RESULTS

At the end of the study, the genistein group had lower level of serum insulin (p = 0.001) and homeostasis model assessment for insulin resistance (HOMA-IR) (p = 0.041) compare to the placebo group. In addition serum malondialdehyde (MDA) (p = 0.004), tumor necrosis factor-α (TNF-α) (p = 0.045) and interleukin (IL)-6 (p = 0.018) also were lower in the genistein group. Compare with placebo, genistein supplementation significantly reduced waist to hip ratio (p = 0.021), body fat percentage (p = 0.015) and triglyceride (p = 0.018). However, there were no significant changes in BMI, fasting blood glucose (p = 0.122), alanine aminotransferase (ALT) (p = 0.536), aspartate aminotransferase (AST) (p = 0.265) between the two groups.

CONCLUSIONS

Oral supplementation with 250 mg genistein for 8-weeks can reduce insulin resistance, oxidative and inflammatory indices along with improvement in fat metabolism in patients with NAFLD. Studies with longer duration and larger samples might be needed to reveal other beneficial effects of genistein.

Hypolipidemic effect of XH601 on hamsters of Hyperlipidemia and its potential mechanism

BACKGROUND

The novel compound XH601 is a synthesized derivative of formononetin. The present study was to investigate the hypolipidemia effect and potential mechanism of XH601.

METHODS

Male Golden Syrian hamsters were induced by high-fat diet (HFD) for eight weeks and the hyperlipidemic model was established successfully. After XH601 treatment, serum and hepatic biochemistry parameters of hamsters were detected and the effect of XH601 on adipose tissue was also analyzed. Furthermore, 3 T3-L1 cell differentiation by Oil-Red-O staining was observed and the mRNA and protein expression of peroxisome proliferator-activated receptors (PPARs) were measured by qRT-PCR and Western-blot in mature adipocytes.

RESULTS

The in vivo results suggest that XH601 significantly decreased the adipose weight and levels of serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), apolipoprotein B (Apo-B), apolipoprotein E (Apo-E), while increased serum high-density lipoprotein (HDL-C). The in vitro results implied that XH601 up-regulated the mRNA and protein expression of both PPARα and PPARβ/δ in a dose-dependent manner.

CONCLUSIONS

The study suggests that XH601 exhibited strong ability to improve the dyslipidemia in hamsters fed with high-fat diet. The potential mechanism of XH601 was associated with the up-regulation of PPARα and PPARβ/δ mRNA and protein expression.

Protective and therapeutic effects of Crataegus aronia in non-alcoholic fatty liver disease

AIM

We evaluated the potential preventive and therapeutic effects of Crataegus aronia (C. aronia) in NAFLD induced by high-fat diet (HFD) in rat models.

METHODS

Protective effect of Crataegus aronia or simvastatin was investigated in Wistar rats fed either low-fat diet (LFD) or HFD.

RESULTS

Liver histopathological examinations confirmed the development of NAFLD in rats fed HFD. In both protective and therapeutic treatments, C. aronia significantly reduced liver index (3.85 ± 0.21% in HFD plus aronia group versus 6.22 ± 0.58% in HFD model group), increased the HDL-cholesterol and reduced the LDL-cholesterol in blood. The hawthorn plant also significantly ameliorated oxidative stress biomarker (p < 0.002) and liver enzymes (p < 0.0001) that indicate liver damage.

CONCLUSION

C. aronia exhibits therapeutic and protective effects on NAFLD in an animal model possibly by its lipid lowering and antioxidant effects; thus, may offer therapeutic potential in humans.

Extract of a polyherbal formulation ameliorates experimental nonalcoholic steatohepatitis

The objective of the present study is to evaluate the effect of the extract of a well-known hepatospecific polyherbal formulation, Liv.52, in an experimental model of high-fat diet (HFD)-induced nonalcoholic steatohepatitis (NASH) in rats. Feeding a HFD for 15 weeks resulted in significant impairment of the lipid profile, elevation of hepatic enzyme markers, and insulin resistance in rats. The histological examination of the liver furthermore indicated fibrotic changes and fat deposition in hepatic tissues. The treatment with Liv.52 extract [125 mg/kg body weight per os (b.wt. p.o.)], which was administered from week 9 onward, reversed the HFD-induced changes to a statistically significant extent, compared to the untreated positive control animals. The effect observed with Liv.52 extract was comparable to that of pioglitazone (4 mg/kg b.wt.), a standard drug that is useful in the management of NASH. The treatment with Liv.52 extract significantly reduced steatosis, collagen deposition, and necrosis in hepatic tissues, which indicates its antifibrotic and antinecrotic properties. The results obtained in the present set of experiments indicate that Liv.52 extract effectively reverses metabolic and histological changes associated with HFD-induced NASH.

Natural antioxidants for non-alcoholic fatty liver disease: molecular targets and clinical perspectives

Non-alcoholic steatohepatitis (NASH), the progressive form of non-alcoholic fatty liver disease (NAFLD), is emerging as a main health problem in industrialized countries. Lifestyle modifications are effective in the treatment of NAFLD; however, the long-term compliance is low. Therefore, several pharmacological treatments have been proposed but none has shown significant efficacy or long-term safety. Natural polyphenols are a heterogeneous class of polyphenolic compounds contained in vegetables, which are being proposed for the treatment of different metabolic disorders. Although the beneficial effect of these compounds has traditionally related to their antioxidant properties, they also exert several beneficial effects on hepatic and extra-hepatic glucose and lipid homeostasis. Furthermore, natural polyphenols exert antifibrogenic and antitumoural effects in animal models, which appear relevant from a clinical point of view because of the association of NASH with cirrhosis and hepatocellular carcinoma. Several polyphenols, such anthocyanins, curcumin and resveratrol and those present in coffee, tea, soy are available in the diet and their consumption can be proposed as part of a healthy diet for the treatment of NAFLD. Other phenolic compounds, such as silymarin, are commonly consumed worldwide as nutraceuticals or food supplements. Natural antioxidants are reported to have beneficial effects in preclinical models of NAFLD and in pilot clinical trials, and thus need clinical evaluation. In this review, we summarize the existing evidence regarding the potential role of natural antioxidants in the treatment of NAFLD and examine possible future clinical applications.

Genistein Attenuates Nonalcoholic Steatohepatitis and Increases Hepatic PPARγ in a Rat Model

Nonalcoholic steatohepatitis (NASH) has become a global chronic liver disease, but no effective medicine has been proven to cure it. This study investigated the protective effects of genistein, a phytoestrogen, on NASH and examined whether it has any effect on hepatic PPARγ. Male Sprague-Dawley rats were divided into four groups: control group fed ad libitum with standard rat diet, NASH group fed ad libitum with high-fat diet to induce NASH and NASH + Gen8 group and NASH + Gen16 group fed with high-fat diet plus intragastric administration of 8 or 16 mg/kg genistein once daily. After 6 weeks, liver samples were collected to determine MDA, TNF-α, PPARγ, and histopathology. The findings were that levels of hepatic MDA and TNF-α increased in NASH group, but 16 mg/kg genistein reduced these levels significantly. Downregulation of hepatic PPARγ was observed in NASH group, but genistein significantly upregulated the expression of PPARγ in both NASH + Gen groups. The histological appearance of liver in NASH group presented pathological features of steatohepatitis which were diminished in both NASH + Gen groups. The results suggest that genistein attenuates the liver histopathology of NASH with upregulation of hepatic PPARγ, reduction of oxidative stress, and inhibition of inflammatory cytokine.

Novel insights into the mechanisms whereby isoflavones protect against fatty liver disease

Fatty liver disease (FLD) is a growing public health problem worldwide. There is an urgent requirement for alternative and natural medicine to treat this disease. As phytochemicals, isoflavones have attracted considerable attention for the prevention of FLD. Numerous studies have revealed that isoflavones protect against FLD through various pathways which modulate fatty acid β-oxidation, lipid synthesis, and oxidative stress. Recently, the aldose reductase (AR)/polyol pathway has been reported to be involved in the development of FLD by modulating hepatic fructose production, peroxisome proliferator-activated receptor (PPAR)α activity, cytochrome P450 (CYP)2E1 expression, and gut bacterial endotoxin-induced cytokine release. It has been reported that some isoflavones are potent AR inhibitors. Here, we review the anti-FLD actions of isoflavones and the proposed mechanism whereby isoflavones protect against FLD, with regard to the AR/polyol pathway. We propose that isoflavones block the AR/polyol pathway and in turn reduce fructose production and subsequent fat accumulation in the liver in diabetic or high-glucose-diet mice. In addition, in rodents with alcoholic liver disease or nonalcoholic fatty liver disease/nonalcoholic steatohepatitis, inhibition of AR by isoflavones may improve PPARα-mediated fatty acid oxidation, reduce hepatic steatosis, and attenuate CYP2E1-mediated oxidative stress or AR/gut bacterial endotoxin-mediated cytokine overproduction, to alleviate progression of FLD.

Thioacetamide-induced liver injury: protective role of genistein

This study aimed to investigate the possible protective effects of genistein (GEN), a phytoestrogen, on the liver injury induced in rats by thioacetamide (TTA; 200.0 mg·(kg body mass)(-1); administered 3 times a week by intraperitoneal injection). GEN (0.5, 1.0, or 2.0 mg·(kg body mass)(-1); by subcutaneous injection) was concurrently administered on a daily basis for 8 weeks, and its effects were evaluated 24 h after the administration of the last dose. The results from this study revealed that TTA-induced liver injury was associated with massive changes in the serum levels of liver biomarkers, oxidative stress markers, and liver inflammatory cytokines. Treatment of TAA-induced liver injury in rats with GEN decreased the elevated serum levels of aspartate aminotransferase, alanine aminotransferase, and total and direct bilirubin, and increased the serum level of albumin. GEN also restored the liver levels of malondialdehyde and reduced glutathione, as well as tumor necrosis factor-alpha, interleukin-6, and their modulator nuclear factor kappa-light-chain-enhancer of activated B cells. From our results, it can be concluded that GEN attenuates the liver injury-induced in rats with TAA, and this hepatoprotective role is attributed to its anti-inflammatory and antioxidant properties.

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.

2-heptyl-formononetin increases cholesterol and induces hepatic steatosis in mice

Consumption of isoflavones may prevent adiposity, hepatic steatosis, and dyslipidaemia. However, studies in the area are few and primarily with genistein. This study investigated the effects of formononetin and its synthetic analogue, 2-heptyl-formononetin (C7F), on lipid and cholesterol metabolism in C57BL/6J mice. The mice were fed a cholesterol-enriched diet for five weeks to induce hypercholesterolemia and were then fed either the cholesterol-enriched diet or the cholesterol-enriched diet-supplemented formononetin or C7F for three weeks. Body weight and composition, glucose homeostasis, and plasma lipids were compared. In another experiment, mice were fed the above diets for five weeks, and hepatic triglyceride accumulation and gene expression and histology of adipose tissue and liver were examined. Supplementation with C7F increased plasma HDL-cholesterol thereby increasing the plasma level of total cholesterol. Supplementation with formononetin did not affect plasma cholesterol but increased plasma triglycerides levels. Supplementation with formononetin and C7F induced hepatic steatosis. However, formononetin decreased markers of inflammation and liver injury. The development of hepatic steatosis was associated with deregulated expression of hepatic genes involved in lipid and lipoprotein metabolism. In conclusion, supplementation with formononetin and C7F to a cholesterol-enriched diet adversely affected lipid and lipoprotein metabolism in C57BL/6J mice.

Development of a cell-based antioxidant activity assay using dietary fatty acid as oxidative stressor

The existing cellular antioxidant activity (CAA) assays always use chemical stressors [e.g. 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)] to initiate oxidative stress (OS), which is not accordance with the pathology of OS-related diseases. In contrast to previous cell models, an oleic acid (OA)-induced OS model of the HepG2 cells was developed in the current work. The antioxidant activities (AAs) of the 16 flavonoid standards in the CAAOA assay were significantly different from the results of the CAAAAPH and peroxyl radical-scavenging assays (PRSA). The AAs of these flavonoids in the PRSA were significantly associated with those of the CAAAAPH assay (r=0.848, P<0.01). On the other hand, isoflavones and epicatechin could significantly attenuate the OS in the CAAOA assay. However, the three flavonoids had no quantifiable AA in CAAAAPH and PRSA. The aforementioned results suggest that the CAAOA assay can probably better reflect the AAs of samples in biological systems.

The role of diet and nutrient composition in nonalcoholic Fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the developed world. NAFLD is tightly linked to insulin resistance and considered to be the hepatic manifestation of the metabolic syndrome. The cornerstone of any treatment regimen for patients with NAFLD is lifestyle modification focused on weight loss, exercise, and improving insulin sensitivity. Here we review the literature and discuss the role of diet and nutrient composition in the management of NAFLD. Because there are currently no specific dietary guidelines for NAFLD, this review proposes a dietary framework for patients with NAFLD based on the available evidence and extrapolates from dietary guidelines aimed at reducing insulin resistance and cardiovascular risk.

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.

Anti-apoptotic and anti-inflammatory effects of Silybum marianum in treatment of experimental steatohepatitis

In this study, we were aimed to evaluate the probable effect of the crud extract of Silybum marianum, with high polyphenolic content, on experimental nonalcoholic steatohepatitis (NASH). To induce NASH, a methionine and choline deficient (MCD) diet was given to N-Mary rats for 8 weeks. After NASH development, MCD-fed rats were divided into two groups: MCD groups received MCD diet and MCD+S group was fed MCD diet plus crude extract of S. marianum orally for 3 weeks. Control group was fed a normal diet for 11 weeks. Finally, all rats were sacrificed. Plasma alanine amino transferase (ALT) and aspartate amino transferase (AST) levels were evaluated. In addition, the following hepatic factors were also evaluated: liver histology, malondialdehyde (MDA) and reduced glutathione (GSH) contents, gene expressions of TNF-α and TGF-β and immunoblot evaluations of caspase-3, ERK/p-ERK, JNK/pJNK and p38/pp38. Histopathological evaluations of the liver samples revealed that treatment with the S. marianum extract has abated the severity of NASH among the MCD-fed rats. Also, a significant reduction was observed in the sera ALT and AST activities. In addition, the extract caused dramatic reduction in the elevated hepatic TNF-α and TGF-β mRNA and MDA levels along with an increase in the GSH content. Moreover, the plant extract treatments significantly lowered activation of procaspase-3 to active caspase-3 and also lowered the phosphorylated form of JNK among the same group of rats. These results suggest that the S. marianum crude extract beneficial effects on NASH are mainly due to its antioxidant and anti-inflammatory activities.

Comparative study on antioxidant capacity of flavonoids and their inhibitory effects on oleic acid-induced hepatic steatosis in vitro

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and its incidence is rising worldwide. We compared the antioxidant capacity of seventeen flavonoids with their inhibitory effects on oleic acid-induced triglyceride (TG) over-accumulation in HepG2 cells. The results showed significant correlations (P < 0.01) between the inhibition of intracellular TG levels and the suppression effects on reactive oxygen species. Nevertheless, the radical-reducing activities of flavonoids assessed by chemical assays (cyclic voltammetry and Folin-Ciocalteu reagent assay) were poorly correlated with their intracellular TG inhibitory effects. The relationships between structural properties of flavonoids and their inhibitory effects on TG over-accumulation were discussed.

Impact of chromium histidinate on high fat diet induced obesity in rats

Background

Chromium (Cr) is an essential trace element that has garnered interest for use as a weight loss aid, but its molecular mechanism in obesity is not clear. In this study, an attempt has been made to investigate the effects of chromium histidinate (CrHis) on glucose transporter-2 (GLUT-2), nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), nuclear factor-kappa B (NF-κB p65) and the oxidative stress marker 4-hydroxynonenal adducts (HNE) expressions in liver of rats fed high fat diet (HFD).

Methods

Male Wistar rats (n = 40, 8 wk-old) were divided into four groups. Group I was fed a standard diet (12% of calories as fat); Group II was fed a standard diet and supplemented with 110 μg CrHis/kg BW/d; Group III was fed a HFD (40% of calories as fat); Group IV was fed HFD and supplemented with 110 μg CrHis/kg BW/d.

Results

Rats fed HFD possessed greater serum insulin (40 vs.33 pmol/L) and glucose (158 vs. 143 mg/dL) concentration and less liver Cr (44 vs.82 μg/g) concentration than rats fed the control diet. However, rats supplemented with CrHis had greater liver Cr and serum insulin and lower glucose concentration in rats fed HFD (P < 0.05). The hepatic nuclear factor-kappa B (NF-κB p65) and HNE were increased in high fat group compared to control group, but reduced by the CrHis administration (P < 0.05). The levels of hepatic Nrf2 and HO-1 were increased by supplementation of CrHis (P < 0.05).

Conclusion

These findings demonstrate that supplementation of CrHis is protective against obesity, at least in part, through Nrf2-mediated induction of HO-1 in rats fed high fat diet.

Neonatal exposure to genistein ameliorates high-fat diet-induced non-alcoholic steatohepatitis in rats

Non-alcoholic steatohepatitis (NASH) is becoming a prevalent disease in developing countries with no effective therapy. Isoflavones such as genistein have been shown to prevent NASH in a rat model, but the effects of neonatal exposure to genistein on lipid metabolism have been rarely studied. In the present study, three doses of genistein (30, 300 or 1200 μg/rat per d) were injected (subcutaneously) into neonatal male Sprague–Dawley rats at postnatal days 1–5. After weaning, these rats were allowed free access to a high-fat diet for 6 weeks. The results demonstrate that NASH was induced by high fat feeding in the control rats, whereas genistein-treated rats displayed smaller body weight, and lower hepatic inflammation and steatosis. The mid dose of genistein was most effective. Neonatal exposure to genistein also resulted in a lower incidence of apoptotic cells in the liver. Additionally, neonatal genistein-treated rats showed lower hepatic expression of fatty acid synthase and sterol regulatory element-binding protein-1, but higher expression of PPARα, indicative of lower rates of lipid synthesis and higher rates of β-oxidation. These results indicate that neonatal treatment with genistein has a prolonged effect on hepatic lipid metabolism that is maintained post-weaning, offering a potential approach for the prevention of hepatic steatosis and NASH.

Comparison of dietary control and atorvastatin on high fat diet induced hepatic steatosis and hyperlipidemia in rats

Background

Treatment with atorvastatin (ATO) or dietary control has been demonstrated to benefit patients with non-alcoholic fatty liver disease (NAFLD) and hyperlipidemia. However, little is known on whether combination of dietary control and ATO treatment could enhance the therapeutic effect.

Methods

We employed a rat model of NAFLD to examine the therapeutic efficacy of dietary control and/or ATO treatment. Sprague-Dawley rats were fed with normal chow diet as normal controls or with high fat diet (HFD) for 12 weeks to establish NAFLD. The NAFLD rats were randomized and continually fed with HFD, with normal chow diet, with HFD and treated with 30 mg/kg of ATO or with normal chow diet and treated with the same dose of ATO for 8 weeks. Subsequently, the rats were sacrificed and the serum lipids, aminotranferase, hepatic lipids, and liver pathology were characterized. The relative levels of fatty acid synthesis and β-oxidation gene expression in hepatic tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Hepatic expression of hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase was determined by Western blot assay.

Results

While continual feeding with HFD deteriorated NAFLD and hyperlipidemia, treatment with dietary control, ATO or ATO with dietary control effectively improved serum and liver lipid metabolism and liver function. In comparison with ATO treatment, dietary control or combined with ATO treatment significantly reduced the liver weight and attenuated the HFD-induced hyperlipidemia and liver steatosis in rats. Compared to ATO treatment or dietary control, combination of ATO and dietary control significantly reduced the levels of serum total cholesterol and low density lipoprotein cholesterol (LDL-C). However, the combination therapy did not significantly improve triglyceride and free fatty acid metabolism, hepatic steatosis, and liver function, as compared with dietary control alone.

Conclusions

ATO treatment effectively improved NAFLD-related hyperlipidemia and inhibited liver steatosis, accompanied by modulating the expression of genes for regulating lipid metabolism. ATO enhanced the effect of dietary control on reducing the levels of serum total cholesterol and LDL-C, but not triglyceride, free fatty acid and hepatic steatosis in HFD-induced fatty liver and hyperlipidemia in rats.

Teucrium polium reversed the MCD diet-induced liver injury in rats

In the present study, we evaluated the ability of Teucrium polium ethyl acetate fraction, with high antioxidant activity, in the treatment of nonalcoholic steatohepatitis (NASH) in rats and its possible effect on factors involved in pathogenesis of the disease. To induce NASH, a methionine and choline deficient (MCD) diet was given to N-Mary rats for 8 weeks. After NASH development, MCD-fed rats were divided into 2 groups: NASH group that received MCD diet and NASH + T group which was fed MCD diet plus ethyl acetate fraction of T. polium orally for 3 weeks. Histopathological evaluations revealed that treatment with the extract has abated the severity of NASH among the MCD-fed rats. In addition, the fraction reduced the elevated levels of hepatic tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-β) gene expression and also the elevated level of malondialdehyde (MDA). In addition, the extract increased the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx) and enhanced the level of hepatic glutathione (GSH). Moreover, the fraction treatments lowered caspase-3 level and the phosphorylated form of C-Jun N-terminal kinase (JNK) and augmented the phosphorylated level of extracellular regulated kinase1/2 (ERK1/2). These results indicate that the ethyl acetate fraction of T. poium effectively reversed NASH, mainly due to its strong antioxidant and anti-inflammatory properties.

The inhibitory effect of genistein on hepatic steatosis is linked to visceral adipocyte metabolism in mice with diet-induced non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has been deeply associated with visceral adiposity, adipose tissue inflammation and a variety of adipocytokines. We reported previously that genistein inhibited NAFLD by enhancing fatty acid catabolism. However, this molecular approach focused on hepatic metabolism. Thus, we have attempted to determine whether this anti-steatotic effect of genistein is linked to visceral adipocyte metabolism. C57BL/6J mice were fed on normal-fat (NF) diet, high-fat (HF) diet and HF diet supplemented with genistein (1, 2 and 4 g/kg diet) for 12 weeks. Mice fed on the HF diet gained body weight, exhibited increased visceral fat mass and elevated levels of serum and liver lipids, and developed NAFLD, unlike what was observed in mice fed on the NF diet. However, genistein supplementation (2 and 4 g/kg diet) normalised these alternations. In the linear regression analysis, visceral fat (R 0·77) and TNFα (R 0·62) were strongly correlated with NAFLD among other NAFLD-related parameters. Genistein supplementation suppressed the hypertrophy of adipocytes via the up-regulation of genes involved in fatty acid β-oxidation, including PPARα, 5'-AMP-activated protein kinase and very long-chain acyl CoA dehydrogenase, as well as through the down-regulation of genes associated with adipogenesis or lipogenesis, including liver X receptor-α, sterol-regulatory element-binding protein-1c, PPARγ, retinoid X receptor-α and acetyl CoA carboxylase 2. Moreover, genistein supplementation augmented an anti-steatohepatitic adiponectin TNF and reduced a steatohepatitic TNFα. Collectively, these findings show that genistein may prevent NAFLD via the regulation of visceral adipocyte metabolism and adipocytokines.

Anti-inflammatory activity of natural dietary flavonoids

Over the past few decades, inflammation has been recognized as a major risk factor for various human diseases. Acute inflammation is short-term, self-limiting and it's easy for host defenses to return the body to homeostasis. Chronic inflammatory responses are predispose to a pathological progression of chronic illnesses characterized by infiltration of inflammatory cells, excessive production of cytokines, dysregulation of cellular signaling and loss of barrier function. Targeting reduction of chronic inflammation is a beneficial strategy to combat several human diseases. Flavonoids are widely present in the average diet in such foods as fruits and vegetables, and have been demonstrated to exhibit a broad spectrum of biological activities for human health including an anti-inflammatory property. Numerous studies have proposed that flavonoids act through a variety mechanisms to prevent and attenuate inflammatory responses and serve as possible cardioprotective, neuroprotective and chemopreventive agents. In this review, we summarize current knowledge and underlying mechanisms on anti-inflammatory activities of flavonoids and their implicated effects in the development of various chronic inflammatory diseases.

A polyphenol extract modifies quantity but not quality of liver fatty acid content in high-fat-high-sucrose diet-fed rats: possible implication of the sirtuin pathway

High-fat or high-fat-high-sucrose diets are known to induce non-alcoholic fatty liver disease and this is emerging as one of the most common liver diseases worldwide. Some polyphenols have been reported to decrease rat hepatic lipid accumulation, in particular those extracted from red grapes such as resveratrol. The present study was designed to determine whether a polyphenol extract (PPE), from red grapes, modulates liver fatty acid composition and desaturase activity indexes in rats fed a high-fat-high-sucrose (HFHS) diet, and to explore whether sirtuin-1 deacetylase activation was implicated in the effect of the PPE against liver steatosis. The effect of this PPE on mitochondriogenesis and mitochondrial activity was also explored. The PPE decreased liver TAG content in HFHS+PPE diet-fed rats in comparison with HFHS diet-fed rats. The PPE had no effect on liver fatty acid composition, desaturase activity indexes and stearoyl-CoA desaturase 1 (SCD1) gene expression. Sirtuin-1 deacetylase protein expression was significantly increased with the PPE; AMP kinase protein expression was higher with the PPE in comparison with the HFHS rats, but no modification of phosphorylated AMP kinase was observed. Protein expression of phospho-acetyl-CoA carboxylase was decreased in HFHS rats and returned to basal values with the PPE. Finally, the PPE modulated PPARγ coactivator-1α (PGC-1α) but did not modify mitochondriogenesis and mitochondrial activity. In conclusion, the PPE partially prevented the accumulation of TAG in the liver by regulating acetyl-CoA carboxylase phosphorylation, a key enzyme in lipid metabolism, probably via sirtuin-1 deacetylase activation. However, the PPE had no effect on the qualitative composition of liver fatty acids.

Genistein suppresses spontaneous oviduct tumorigenesis in quail

Spontaneous leiomyomas of the oviduct are common tumors of the Japanese quail (Coturnix coturnix japonica) and laying hens. This makes it a good animal model for screening potential agents for testing in the prevention and treatment of human myoma uteri. Genistein has been shown to inhibit the growth of various cancer cells. We investigated the effects of genistein supplementation on the development of fibroid tumors in the oviduct, serum oxidative stress markers [malondialdehyde (MDA), 8-isoprostane, 4-hydroxyalkenal (HAE), 8-hydroxy-2' -deoxyguanosine (8-OHdG) levels], soy isoflavone levels, and tissue biomarkers [Connexin 43 (Cx43), Bcl-2, and Bax and heat shock protein 70 (Hsp70) expression] in Japanese quail. One hundred and fifty quail (12 mo old) were assigned to 3 experimental groups as 5 replicates of pens containing 10 birds in each. Birds were fed either a basal diet or the basal diet supplemented with 400 mg or 800 mg of genistein/kg of diet. The animals were sacrificed after 315 days, and the tumors were identified. Genistein supplementation significantly decreased the incidence of fibroid tumors as compared to control birds (P = 0.04). The tumors in genistein-fed birds were smaller than those found in control birds (P = 0.02). Serum MDA, 8-isoprostane, and HAE levels were lower in treatment groups than in control group (MDA: 2.01 vs. 0.82; 8-isoprostane: 135 vs. 101; HAE: 1.45 vs. 0.73; P <or= 0.01). The concentrations of serum 8-OHdG, which is a marker of oxidative damage, in the groups were 27.5, 22.4, and 21.3 ng/ml, respectively (P = 0.05). The expression of cell cycle regulatory proteins, Bcl-2, was 4.18 and 4.61 in the genistein groups and 6.21 in the control group, and the expression of Bax was 10.93 and 16.78 in the genistein groups and 7.60 in the control group (P < 0.001 for Bax). Cx43 level was 2.56 and 2.40 in the genistein groups compared with 5.15 in the control group. None of the differences in the Cx43 and Bcl-2 of the groups were significant. The expression of heat shock proteins, Hsp60 and Hsp70, were not different between groups, although Hsp70 level of the genistein groups (19.73) was lower than the control group (27.8). The results indicate that dietary supplementation of genistein reduces the incidence and size of spontaneously occurring leiomyoma of the oviduct in the Japanese quail. Clinical trials should be conducted to investigate the efficacy of genistein supplementation in the prevention and treatment of uterine leiomyoma in humans.

Genistein improves liver function and attenuates non-alcoholic fatty liver disease in a rat model of insulin resistance

BACKGROUND

The high fructose-fed rat is widely used as a model of insulin resistance. Genistein, a soy isoflavone, has been shown to improve insulin sensitivity in this model. The present study investigated whether genistein could prevent fatty liver disease in this model.

METHODS

Male Wistar rats were fed a diet containing starch (control) or 60% fructose (insulin-resistant model). Fifteen days later, rats in each dietary group were divided into two groups and were treated with either genistein (1 mg/kg per day) in dimethylsulfoxide (DMSO) or 30% DMSO alone. After 60 days, markers of liver injury, oxidative stress, interleukin (IL)-6, tumor necrosis factor (TNF)-α, lipids, lipoprotein profile, nitrite, and nitrosothiol in the plasma and liver were quantified. Liver sections were examined for 3-nitrotyrosine (3-NT) expression and pathological lesions.

RESULTS

Fructose-fed rats displayed hyperlipidemia, significant changes in plasma lipoprotein profile, and increases in IL-6 and TNF-α levels compared with control. In addition, the accumulation of lipids, liver injury, a decline in liver function, inactivation of the glyoxalase system, depletion of antioxidants, and increased 3-NT expression were observed in the fructose-fed group. Administration of genistein to fructose-fed rats significantly reduced these biochemical and histological abnormalities.

CONCLUSIONS

Genistein activates the antioxidant profile, decreases IL-6 and TNF-α concentrations, prevents oxidative damage, and ameliorates fatty liver in insulin-resistant rats.

Resveratrol inhibits nonalcoholic fatty liver disease in rats

BACKGROUND

The prevalence of nonalcoholic fatty liver disease (NAFLD) is high. NAFLD is linked to obesity, diabetes mellitus, and hypertriglyceridemia. Approximately 20% of patients with NAFLD will eventually develop cirrhosis. Our purpose was to investigate whether resveratrol decreased hepatic steatosis in an animal model of steatosis, and whether this therapeutic approach resulted in a decrease in tumor necrosis factor alpha (TNF-alpha) production, lipid peroxidation and oxidative stress.

METHODS

Male Wistar CRL: Wi (Han) (225 g) rats were randomized into three groups. A control group (n = 12) was given free access to regular dry rat chow for 4 weeks. The steatosis (n = 12) and resveratrol (n = 12) groups were given free access to feed (a high carbohydrate-fat free modified diet) and water 4 days per week, and fasted for the remaining 3 days for 4 weeks. Rats in the resveratrol group were given resveratrol 10 mg daily by the oral route. All rats were killed at 4 weeks and assessed for fatty infiltration and bacterial translocation. Levels of TNF-alpha in serum, hepatic malondialdehyde (MDA), oxidative stress (superoxide dismutase, glutathione peroxidase, catalase and nitric oxide synthase) and biochemical parameters were measured.

RESULTS

Fat deposition was decreased in the resveratrol group as compared to the steatosis group (Grade 1 vs Grade 3, P < 0.05). TNF-alpha and MDA levels were significantly increased in the steatosis group (TNF-alpha; 33.4 +/- 5.2 vs 26.24 +/- 3.47 pg/ml and MDA; 9.08 +/- 0.8 vs 3.17 +/- 1.45 muM respectively, P < 0.05). This was accompanied by increased superoxide dismutase, glutathione peroxidase and catalase and decreased nitric oxide synthase in the liver of resveratrol group significantly (P < 0.05 vs steatosis group). Bacterial translocation was not found in any of the groups. Glucose levels were decreased in the group of rats given resveratrol (P < 0.05).

CONCLUSION

Resveratrol decreased NAFLD severity in rats. This effect was mediated, at least in part, by TNF-alpha inhibition and antioxidant activities.