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

Identification of dihydromyricetin as a natural DNA methylation inhibitor with rejuvenating activity in human skin

Changes in DNA methylation patterning have been reported to be a key hallmark of aged human skin. The altered DNA methylation patterns are correlated with deregulated gene expression and impaired tissue functionality, leading to the well-known skin aging phenotype. Searching for small molecules, which correct the aged methylation pattern therefore represents a novel and attractive strategy for the identification of anti-aging compounds. DNMT1 maintains epigenetic information by copying methylation patterns from the parental (methylated) strand to the newly synthesized strand after DNA replication. We hypothesized that a modest inhibition of this process promotes the restoration of the ground-state epigenetic pattern, thereby inducing rejuvenating effects. In this study, we screened a library of 1800 natural substances and 640 FDA-approved drugs and identified the well-known antioxidant and anti-inflammatory molecule dihydromyricetin (DHM) as an inhibitor of the DNA methyltransferase DNMT1. DHM is the active ingredient of several plants with medicinal use and showed robust inhibition of DNMT1 in biochemical assays. We also analyzed the effect of DHM in cultivated keratinocytes by array-based methylation profiling and observed a moderate, but significant global hypomethylation effect upon treatment. To further characterize DHM-induced methylation changes, we used published DNA methylation clocks and newly established age predictors to demonstrate that the DHM-induced methylation change is associated with a reduction in the biological age of the cells. Further studies also revealed re-activation of age-dependently hypermethylated and silenced genes in vivo and a reduction in age-dependent epidermal thinning in a 3-dimensional skin model. Our findings thus establish DHM as an epigenetic inhibitor with rejuvenating effects for aged human skin.

Metabolism of phenolics in coffee and plant-based foods by canonical pathways: an assessment of the role of fatty acid β-oxidation to generate biologically-active and -inactive intermediates

ω-Phenyl-alkenoic acids are abundant in coffee, fruits, and vegetables. Along with ω-phenyl-alkanoic acids, they are produced from numerous dietary (poly)phenols and aromatic amino acids in vivo. This review addresses how phenyl-ring substitution and flux modulates their gut microbiota and endogenous β-oxidation. 3',5'-Dihydroxy-derivatives (from alkyl-resorcinols, flavanols, proanthocyanidins), and 4'-hydroxy-phenolic acids (from tyrosine, p-coumaric acid, naringenin) are β-oxidation substrates yielding benzoic acids. In contrast, 3',4',5'-tri-substituted-derivatives, 3',4'-dihydroxy-derivatives and 3'-methoxy-4'-hydroxy-derivatives (from coffee, tea, cereals, many fruits and vegetables) are poor β-oxidation substrates with metabolism diverted via gut microbiota dehydroxylation, phenylvalerolactone formation and phase-2 conjugation, possibly a strategy to conserve limited pools of coenzyme A. 4'-Methoxy-derivatives (citrus fruits) or 3',4'-dimethoxy-derivatives (coffee) are susceptible to hepatic "reverse" hydrogenation suggesting incompatibility with enoyl-CoA-hydratase. Gut microbiota-produced 3'-hydroxy-4'-methoxy-derivatives (citrus fruits) and 3'-hydroxy-derivatives (numerous (poly)phenols) are excreted as the phenyl-hydracrylic acid β-oxidation intermediate suggesting incompatibility with hydroxy-acyl-CoA dehydrogenase, albeit with considerable inter-individual variation. Further investigation is required to explain inter-individual variation, factors determining the amino acid to which C6-C3 and C6-C1 metabolites are conjugated, the precise role(s) of l-carnitine, whether glycine might be limiting, and whether phenolic acid-modulation of β-oxidation explains how phenolic acids affect key metabolic conditions, such as fatty liver, carbohydrate metabolism and insulin resistance.

Myricetin inhibits pseudorabies virus infection through direct inactivation and activating host antiviral defense

Myricetin, a polyhydroxyflavone compound, is one of the main ingredients of various human foods and therefore also known as dietary flavonoids. Due to the continuous emergence of resistant strains of herpesviruses, novel control measures are required. In the present study, myricetin exhibited potent antiviral activity against pseudorabies virus (PRV), a model organism of herpesvirus. The suppression rate could reach up to 96.4% at a concentration of 500 μM in cells, and the 50% inhibitory concentration (IC50) was 42.69 μM. Moreover, the inhibitory activity was not attenuated by the increased amount of infective dose, and a significant reduction of intracellular PRV virions was observed by indirect immunofluorescence. A mode of action study indicated that myricetin could directly inactivate the virus in vitro, leading to inhibition of viral adsorption, penetration and replication in cells. In addition to direct killing effect, myricetin could also activate host antiviral defense through regulation of apoptosis-related gene expressions (Bcl-2, Bcl-xl, Bax), NF-κB and MAPK signaling pathways and cytokine gene expressions (IL-1α, IL-1β, IL-6, c-Jun, STAT1, c-Fos, and c-Myc). In PRV-infected mouse model, myricetin could enhance the survival rate by 40% at 5 days post infection, and viral loads in kidney, liver, lung, spleen, and brain were significantly decreased. The pathological changes caused by PRV infection were improved by myricetin treatment. The gene expressions of inflammatory factors (MCP-1, G-CSF, IL-1α, IL-1β, and IL-6) and apoptotic factors (Bcl-xl, Bcl-2, and Bax) were regulated by myricetin in PRV-infected mice. The present findings suggest that myricetin can effectively inhibit PRV infection and become a candidate for development of new anti-herpesvirus drugs.

Myricetin protects natural killer cells from arsenite induced DNA damage by attenuating oxidative stress and retaining poly(ADP-Ribose) polymerase 1 activity

Environmental exposure to arsenite (As⁺³) is known to induce immunotoxicity. Natural killer (NK) cells are innate lymphoid cells act as professional killers of tumor cells. Our previous report indicated that 500 ppb As⁺³ drinking water exposure induced significant DNA damage in the NK cells of C57BL/6 mice. Myricetin is a plant-derived flavonoid known as a strong antioxidant. In this study, daily administration of myricetin at 20 mg/kg was found to alleviate the cell population decrease and DNA damage in the NK cells of BALB/c mice exposed to 500 and 1000 ppb As⁺³ via drinking water. Oxidative stress and poly(ADP-ribose) polymerase 1 (PARP-1) inhibition were induced by As⁺³ at 1 and 2 μM in isolated mouse NK cells in vitro, which were attenuated by 20 μM myricetin. The mitigatory effect of myricetin on the PARP-1 inhibition in NK cells treated with As⁺³ was also found to be the result of its prevention of the zinc loss induced by As⁺³ on PARP-1. Collectively, these results demonstrated, for the first time, that myricetin could protect NK cells from As⁺³ induced DNA through attenuating oxidative stress and retaining PARP-1 activity, indicating that myricetin may be utilized for the prevention of the immunotoxicity induced by As⁺³ in NK cells.

Antioxidant Capacity of Proteins and Hydrolysates from the Liver of Newborn Piglets, and Their Inhibitory Effects on Steatosis in vitro

Research background

Non-alcoholic steatohepatitis is a potentially progressive hepatic disorder that can lead to end-stage liver disease and hepatocellular carcinoma. The inhibitory effects of proteins and hydrolysates from the liver of newborn piglets on hepatic steatosis in oleic acid-induced hepatocellular carcinoma (HepG2) cells were investigated in vitro.

Experimental approach

The extracted proteins from the liver of newborn piglets were hydrolysed with papain, pepsin, trypsin and Alcalase. Based on the comparison of different enzyme digestion conditions, a protein hydrolysis protocol was established to obtain hydrolysates with lipid-lowering effect.

Results and conclusions

Trypsin-digested liver protein hydrolysate from newborn piglets exhibited strong antioxidant activity and good inhibitory effects against lipogenesis and cholesterol accumulation in HepG2 cells at the concentration of 150 μg/mL, with a triglyceride decrease of (43±3) % and cholesterol decrease of (31±5) %, compared with model group induced with 0.75 mM oleic acid. The addition of trypsin-digested liver protein hydrolysate from newborn piglets (300 μg/mL) decreased alanine aminotransferase and aspartate aminotransferase activities and increased superoxide dismutase activity.

Novelty and scientific contribution

This study demonstrated that the trypsin-digested liver protein hydrolysate from newborn piglets has a potential preventive effect against non-alcoholic fatty liver disease in its early stage, and a potential use as the modulator of lipid overaccumulation in form of food supplements.

Myricetin as a Promising Molecule for the Treatment of Post-Ischemic Brain Neurodegeneration

The available drug therapy for post-ischemic neurodegeneration of the brain is symptomatic. This review provides an evaluation of possible dietary therapy for post-ischemic neurodegeneration with myricetin. The purpose of this review was to provide a comprehensive overview of what scientists have done regarding the benefits of myricetin in post-ischemic neurodegeneration. The data in this article contribute to a better understanding of the potential benefits of myricetin in the treatment of post-ischemic brain neurodegeneration, and inform physicians, scientists and patients, as well as their caregivers, about treatment options. Due to the pleiotropic properties of myricetin, including anti-amyloid, anti-phosphorylation of tau protein, anti-inflammatory, anti-oxidant and autophagous, as well as increasing acetylcholine, myricetin is a promising candidate for treatment after ischemia brain neurodegeneration with full-blown dementia. In this way, it may gain interest as a potential substance for the prophylaxis of the development of post-ischemic brain neurodegeneration. It is a safe substance, commercially available, inexpensive and registered as a pro-health product in the US and Europe. Taken together, the evidence available in the review on the therapeutic potential of myricetin provides helpful insight into the potential clinical utility of myricetin in treating neurodegenerative disorders with full-blown dementia. Therefore, myricetin may be a promising complementary agent in the future against the development of post-ischemic brain neurodegeneration. Indeed, there is a scientific rationale for the use of myricetin in the prevention and treatment of brain neurodegeneration caused by ischemia.

Beneficial Effects of Plant-Derived Natural Products on Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is becoming in one of the most prevalent liver diseases that leads to liver transplantation. This health problem is a multisystem disease with a complex pathogenesis that involves liver, adipose tissue, gut, and muscle. Although several pharmacological agents have been investigated to prevent or treat non-alcoholic fatty liver disease, currently there is no effective treatment for the management of this chronic liver disease. Nonetheless, the use of natural products has emerged as a alternative therapeutic for the treatment of hepatic diseases, including non-alcoholic fatty liver disease, due to its anti-inflammatory, antioxidant, antidiabetic, insulin-sensitizing, antiobesity, hypolipidemic, and hepatoprotective properties. In the present review, we have discussed the evidence from experimental and clinical studies regarding the potential beneficial effects of plant-derived natural products (quercetin, resveratrol, berberine, pomegranate, curcumin, cinnamon, green tea, coffee, garlic, ginger, ginseng, and gingko biloba) for the treatment or prevention of non-alcoholic fatty liver disease.

Molecular Level Insight Into the Benefit of Myricetin and Dihydromyricetin Uptake in Patients With Alzheimer's Diseases

Alzheimer's disease (AD) is a neurodegenerative disease with a high incidence rate and complicated pathogenesis. Currently, all anti-AD drugs treat the symptoms of the disease, and with currently no cure for AD. Flavonoid containing natural products, Myricetin (MYR) and Dihydromyricetin (DMY), are abundant in fruits and vegetables, and have been approved as food supplements in some countries. Interestingly, MYR and DMY have been reported to have anti-AD effects. However, the underlying anti-AD mechanism of action of MYR and DMY is complex with many facets being identified. In this review, we explore the benefit of MYR and DMY in AD patients from a molecular level. Their mechanism of action are discussed from various aspects including amyloid β-protein (Aβ) imbalance, neuroinflammation, dyshomeostasis of metal ions, autophagy disorder, and oxidative stress.

Myricetin bioactive effects: moving from preclinical evidence to potential clinical applications

Several flavonoids have been recognized as nutraceuticals, and myricetin is a good example. Myricetin is commonly found in plants and their antimicrobial and antioxidant activities is well demonstrated. One of its beneficial biological effects is the neuroprotective activity, showing preclinical activities on Alzheimer, Parkinson, and Huntington diseases, and even in amyotrophic lateral sclerosis. Also, myricetin has revealed other biological activities, among them as antidiabetic, anticancer, immunomodulatory, cardiovascular, analgesic and antihypertensive. However, few clinical trials have been performed using myricetin as nutraceutical. Thus, this review provides new insights on myricetin preclinical pharmacological activities, and role in selected clinical trials.

Optimization of betacyanins from agricultural by-products using pressurized hot water extraction for antioxidant and in vitro oleic acid-induced steatohepatitis inhibitory activity

Pressurized hot water extraction (PHWE) is proposed to recover betacyanins from agricultural by-products (pitaya fruits peels (PFP), red beet stalks (RBS), and cactus pear peels (CPP)). The extraction yield of betacyanins was optimized by response surface methodology. The optimal PHWE conditions were attained and the actual yields of betacyanins under optimal conditions were well matched with the predicted yields. In addition, betacyanin pigment compositions as well as superoxide anion scavenging activity of individual betacyanins extract (BE) produced in optimal PHWE conditions were characterized by HPLC-ESI/MSⁿ and cyclic voltammetry. Furthermore, the inhibitory activity of three BEs on oleic acid-induced steatohepatitis in cellular model was comparatively investigated. The results showed that unlike PFP, RBS, and CPP presented excellent efficacy in decreasing intracellular triglyceride and reactive oxygen species, inhibiting the release of alanine aminotransferase and aspartate aminotransferase as well as regulating fatty acid synthase and carnitine palmitoyltransferase 1 mRNAs expression. Practical applications In this study, PHWE, is firstly proposed for the enhancement of the extraction of betacyanins from three agricultural by-products. Betacyanin-rich extracts by PHWE method exhibit excellent activities in inhibition of ROS and regulation of lipid metabolism in hepatic cells. It suggests that PHWE has a strong potentiality in keeping bioactivity of BEs, which is significant for the production of betacyanins functional foods.

Myricetin inhibits NLRP3 inflammasome activation via reduction of ROS-dependent ubiquitination of ASC and promotion of ROS-independent NLRP3 ubiquitination

Myricetin is a plant-derived flavonoid that exhibits diverse pharmacological properties. The NLRP3 (NLR family, pyrin domain-containing 3 protein) inflammasome is a cytosolic multiprotein complex that plays a critical role in the innate immune response and pathogenesis of multiple inflammatory disorders. The present study found that myricetin inhibited NLRP3 inflammasome assembly via promotion of reactive oxygen species (ROS)-independent ubiquitination of NLRP3 and reduction of ROS-dependent ubiquitination of ASC (apoptosis-associated speck-like protein containing a CARD), which disrupted the interaction between ASC and NLRP3 and inhibited ASC oligomerization. This effect was further confirmed in vivo using mouse models of lipopolysaccharide (LPS)-induced sepsis and alum-induced peritonitis. These results suggest the therapeutic value of myricetin by targeting NLRP3-driven inflammatory diseases.

Protective Effects of Five Structurally Diverse Flavonoid Subgroups against Chronic Alcohol-Induced Hepatic Damage in a Mouse Model

Alcoholic liver disease (ALD) has become one of the major global health problems, with augmented morbidity and mortality. Evidence indicates that flavonoids can reduce the risk of ALD owing to their biological properties. However, the effect of structurally different flavonoid subclasses on alleviating alcohol-induced liver damage in a same model has never been studied. In this study, mice were supplemented with five kinds of flavonoid subgroups, apigenin (flavone), quercetin (flavonol), naringenin (flavanone), (-)-epigallocatechin gallate (flavanol), and genistein (isoflavone), in the same dose (0.3 mmol kg⁻¹ body weight) and then given 50% alcohol by gastric perfusion for five consecutive weeks. The results demonstrated that genistein and naringenin had greater benefits in terms of mitigating fibrosis and apoptosis, respectively, in the liver. Lipid deposition, partial inflammatory-related factors (nuclear factor kappa B p65, cyclooxygenase-2, and interleukin-6 levels), and hepatic histopathological alterations were similarly attenuated by five kinds of flavonoids. All the flavonoids also showed different degrees of influence on protecting against alcoholic liver injury on other aspects, such as serum biochemistry makers, hepatic lipid accumulation, lipid peroxidation, antioxidant capacities, and inflammation.

Anthocyanin-rich extracts from blackberry, wild blueberry, strawberry, and chokeberry: antioxidant activity and inhibitory effect on oleic acid-induced hepatic steatosis in vitro

BACKGROUND

Limited information is available regarding the relationship between the chemical structures and inhibitory effects of anthocyanin (ACN) on triglyceride (TG) overaccumulation. Thus this study investigated the antioxidant activity and inhibitory effect of blackberry, wild blueberry, strawberry, and chokeberry ACN-rich extracts, with different structural characteristics, on oleic acid-induced hepatic steatosis in vitro. Four major ACNs from these berries, with different aglycones, namely cyanidin-3-glucoside (Cy-3-glu), delphinidin-3-glucoside, pelargonidin-3-glucoside, and malvidin-3-glucoside, were also investigated.

RESULTS

Blackberry ACN-rich extract exhibited the most significant inhibitory effect on TG clearance (30.5% ± 3.4%) and reactive oxygen species generation. TG clearance was significantly correlated with total phenolic content (r = 0.991, P < 0.05) and oxygen radical absorbance capacity value (r = 0.961, P < 0.05). Furthermore, Cy-3-glu showed the highest inhibitory effect on intracellular TG overaccumulation, with a maximum TG clearance of 61.3% at 40 µg mL(-1) .

CONCLUSION

Our findings suggest that the inhibitory effects of different ACNs on oleic acid-induced hepatic steatosis significantly vary. Cy-3-glu, which contains the ortho hydroxyl group in its B ring, possibly confers the protective effects of antioxidants and inhibits TG accumulation in HepG2 cells. © 2015 Society of Chemical Industry.

Myricetin: A Dietary Molecule with Diverse Biological Activities

Myricetin is a common plant-derived flavonoid and is well recognised for its nutraceuticals value. It is one of the key ingredients of various foods and beverages. The compound exhibits a wide range of activities that include strong anti-oxidant, anticancer, antidiabetic and anti-inflammatory activities. It displays several activities that are related to the central nervous system and numerous studies have suggested that the compound may be beneficial to protect against diseases such as Parkinson's and Alzheimer's. The use of myricetin as a preserving agent to extend the shelf life of foods containing oils and fats is attributed to the compound's ability to protect lipids against oxidation. A detailed search of existing literature revealed that there is currently no comprehensive review available on this important molecule. Hence, the present work includes the history, synthesis, pharmaceutical applications and toxicity studies of myricetin. This report also highlights structure-activity relationships and mechanisms of action for various biological activities.

Methylation of flavonoids: Chemical structures, bioactivities, progress and perspectives for biotechnological production

Among the natural products, flavonoids have been particularly attractive, highly studied and become one of the most important promising agent to treat cancer, oxidant stress, pathogenic bacteria, inflammations, cardio-vascular dysfunctions, etc. Despite many promising roles of flavonoids, expectations have not been fulfilled when studies were extended to the in vivo condition, particularly in humans. Instability and very low oral bioavailability of dietary flavonoids are the reasons behind this. Researches have demonstrated that the methylation of these flavonoids could increase their promise as pharmaceutical agents leading to novel applications. Methylation of the flavonoids via theirs free hydroxyl groups or C atom dramatically increases their metabolic stability and enhances the membrane transport, leading to facilitated absorption and highly increased oral bioavailability. In this paper, we concentrated on analysis of flavonoid methoxides including O- and C-methoxide derivatives in aspect of structure, bioactivities and description of almost all up-to-date O- and C-methyltransferases' enzymatic characteristics. Furthermore, modern biological approaches for synthesis and production of flavonoid methoxides using metabolic engineering and synthetic biology have been focused and updated up to 2015. This review will give a handful information regarding the methylation of flavonoids, methyltransferases and biotechnological synthesis of the same.

Strategies, models and biomarkers in experimental non-alcoholic fatty liver disease research

Non-alcoholic fatty liver disease encompasses a spectrum of liver diseases, including simple steatosis, steatohepatitis, liver fibrosis and cirrhosis and hepatocellular carcinoma. Non-alcoholic fatty liver disease is currently the most dominant chronic liver disease in Western countries due to the fact that hepatic steatosis is associated with insulin resistance, type 2 diabetes mellitus, obesity, metabolic syndrome and drug-induced injury. A variety of chemicals, mainly drugs, and diets is known to cause hepatic steatosis in humans and rodents. Experimental non-alcoholic fatty liver disease models rely on the application of a diet or the administration of drugs to laboratory animals or the exposure of hepatic cell lines to these drugs. More recently, genetically modified rodents or zebrafish have been introduced as non-alcoholic fatty liver disease models. Considerable interest now lies in the discovery and development of novel non-invasive biomarkers of non-alcoholic fatty liver disease, with specific focus on hepatic steatosis. Experimental diagnostic biomarkers of non-alcoholic fatty liver disease, such as (epi)genetic parameters and '-omics'-based read-outs are still in their infancy, but show great promise. In this paper, the array of tools and models for the study of liver steatosis is discussed. Furthermore, the current state-of-art regarding experimental biomarkers such as epigenetic, genetic, transcriptomic, proteomic and metabonomic biomarkers will be reviewed.

Anthocyanins-rich extract of wild Chinese blueberry protects glucolipotoxicity-induced INS832/13 β-cell against dysfunction and death

As commonly observed events in diabetic patients, glucolipotoxicity induces oxidative stress, apoptosis and functional defects in β-cells. Anthocyanins are well investigated as strong antioxidants and modulators for metabolic syndromes. Therefore, this study examined the protective effects of anthocyanins-rich extracts (BAE) from wild Chinese blueberry (Vaccinium spp.) against glucolipotoxicity in β-cells. Results showed that INS832/13 β-cells subjected to glucolipotoxicity were significantly decreased (p < 0.05) in cell survival rate, which were alleviated by BAE and metformin treatments. Both BAE and metformin reduced reactive oxidative species and improved the antioxidant defense system. Moreover, BAE were effective in reducing intracellular triglycerides (TG) level, restoring intracellular insulin content, lowering basal insulin secretion (BIS) and increasing glucose-stimulated insulin secretion which in turn resulted in an elevated insulin secretion index. However, metformin only demonstrated marginal effect on secretion dysfunction and had no effect (p > 0.05) on BIS or TG. Additionally, TG levels reduced by BAE treatment were correlated with BIS (p < 0.01, r = 0.9755). This study has for the first time demonstrated that anthocyanin enriched extract of wild Chinese blueberry could effectively protect β-cells against glucolipotoxicity in vitro. These results implied the potential efficacy of BAE as a complementary measure for diabetes intervention.

A diet formula of Puerariae radix, Lycium barbarum, Crataegus pinnatifida, and Polygonati rhizoma alleviates insulin resistance and hepatic steatosis in CD-1 mice and HepG2 cells

According to the principles of traditional Chinese medicine, medicinal and edible herbs exhibit holistic effects through their actions on multiple target organs.

The effects of intermittent hypoxia on redox status, NF-κB activation, and plasma lipid levels are dependent on the lowest oxygen saturation

Obstructive sleep apnea syndrome (OSAS) is described as repetitive obstructions of the upper airways during sleep, causing concomitant episodes of systemic hypoxia and associated cardiovascular and metabolic pathologies. The mechanisms generating these pathologies are controversial. Because recurrent hypoxia is the element of inadequate respiration that leads to the pathology, experimental models of OSAS consist in the exposure of the animals to intermittent hypoxia (IH) by cycling O2 percentages in their habitats. A proposed mechanism linking the IH of OSAS to pathologies is the increased production of reactive oxygen species (ROS). However, it has been argued that many patients seem to lack oxidative stress and that, to augment ROS in IH animals, intense hypoxia, seldom encountered in patients, has to be applied. To solve the controversy, we have exposed rats to two intensities of IH (cycles of 10 or 5% O2, 40s, and then 21% O2, 80s; 8h/day, 15 days). We then measured reduced and oxidized glutathione and lipid peroxide levels, aconitase and fumarase activities, and ROS-disposal enzyme activity in liver, brain, and lung. Liver levels of nuclear NF-κB-p65 and plasma C-reactive protein (CRP), as well as lipid levels, were also assessed. Lowest hemoglobin saturations were 91.7 ± 0.8 and 73.5 ± 1.4%. IH caused tissue-specific oxidative stress related to hypoxic intensity. Nuclear NF-κB-p65 and lipid content in the liver and CRP in the plasma all increased with IH intensity, as did both plasma triglycerides and cholesterol. We conclude that IH, even of moderate intensity, causes oxidative stress probably related to the pathologies encountered in OSAS patients.

Water Soluble Vitamin E Administration in Wistar Rats with Non-alcoholic Fatty Liver Disease

OBJECTIVE

A diet rich in fat is associated with hepatic fat deposition [steatosis; non-alcoholic fatty liver disease (NAFLD)]. The exact cause of NAFLD however, is still unknown. The aim of this study was to assess the effect of a water-soluble formulation of vitamin E on a dietary-induced-NAFLD animal model.

METHODS

Adult male Wistar rats (n=20) were allocated to 2 groups: Controls (Group A, n=6), which received a standard chow diet for 24 weeks and a High Cholesterol group (HC: n=14), which received a standard chow diet enriched with cholesterol for the first 14 weeks of the experiment (t(1)). At t(1), the HC group was divided into: Group HC(B), which received a high-saturated-fat/high-cholesterol (HSF/HCH) diet and Group HC(C), which followed the same HSF/HCH diet but was also administered water soluble vitamin E (10 IU/kg body weight/day), for 10 more weeks.

RESULTS

At the end of the study, group HC(C) exhibited significantly lower mean total cholesterol (T-CHOL) than group HC(B) (p<0.001). No significant differences were observed between HC(C) and Control groups in blood glucose and serum lipid concentrations. Liver Function Tests did not vary between all groups at the end of the study. Animals in group HC(B) exhibited higher SGOT at the end of the study compared with the beginning of the study (p<0.05). Group HC(B) exhibited the highest scores in steatosis, and grading (according to the NAFLD scoring system) in the histopathological analysis (p≤0.001 in all cases).

CONCLUSIONS

Vitamin E seems to exert a hypolipidemic and hepatoprotective role in the presence of a HSF/HCH atherogenic diet in a rat model.