Identification of urolithin a as a metabolite produced by human colon microflora from ellagic acid and related compounds

Dietary ellagic acid and related polyphenols are metabolized in humans to dibenzopyran-6-one derivatives, and the microbial origin of these metabolites has been suggested. However, this has not been demonstrated so far. Fecal samples donated by six volunteers were incubated under anaerobic conditions, and aliquots were used to evaluate the fecal metabolism of ellagic acid, the ellagitannin punicalagin, and an ellagitannin rich extract from walnuts. The isoflavone daidzein was also incubated with the same fecal samples to follow the production of the microbial metabolites previously reported (dihydrogenistein, O-demethylangolensin, and equol) as a positive control of the system and to evaluate similarities between isoflavone and ellagic acid fecal flora metabolism. After fermentation the metabolite "urolithin A" (3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one) was produced from ellagic acid, punicalagin, and the ellagitannin extract in all the fecal cultures from different volunteers, but with very different production rates and concentrations. This large variability in the concentration of metabolite and kinetics of metabolite production is consistent with the large variability found in the excretion of these metabolites in urine in vivo after human consumption of ellagitannins, and with differences in the composition of the fecal microflora. No correlation between isoflavone and ellagic acid metabolism by fecal microflora was observed. The present study confirms the microbial origin of the recently reported in vivo generated hydroxy-6H-dibenzo[b,d]pyran-6-one derivatives in humans and is a further step in the study of the bioavailability and metabolism of ellagic acid and ellagitannins.

Potential impact of strawberries on human health: a review of the science

Epidemiological studies have noted a consistent association between the consumption of diets rich in fruits and vegetables and a lower risk for chronic diseases including cancer and cardiovascular disease. There is accumulating evidence that much of the health-promoting potential of these plant foods may come from phytochemicals, bioactive compounds not designated as traditional nutrients. In strawberries, the most abundant of these are ellagic acid, and certain flavonoids: anthocyanin, catechin, quercetin and kaempferol. These compounds in strawberries have potent antioxidant power. Antioxidants help lower risk of cardiovascular events by inhibition of LDL-cholesterol oxidation, promotion of plaque stability, improved vascular endothelial function, and decreased tendency for thrombosis. Furthermore, strawberry extracts have been shown to inhibit COX enzymes in vitro, which would modulate the inflammatory process. Individual compounds in strawberries have demonstrated anticancer activity in several different experimental systems, blocking initiation of carcinogenesis, and suppressing progression and proliferation of tumors. Preliminary animal studies have indicated that diets rich in strawberries may also have the potential to provide benefits to the aging brain.

Low concentrations of quercetin and ellagic acid synergistically influence proliferation, cytotoxicity and apoptosis in MOLT-4 human leukemia cells

Little information is available regarding possible synergistic or antagonistic biochemical interactions among polyphenols contained in fruits and vegetables. Identifying potential interactions among these compounds may help to define the efficiency of polyphenol-containing foods in cancer prevention as related to structure-function activity of the compounds. The objective of this study was to investigate interactions between quercetin and ellagic acid, two polyphenolics that are present predominantly in small fruits, on cell death and proliferation-related variables in the MOLT-4 human leukemia cell line. Assays were performed to determine cell cycle kinetics, proliferation, apoptotic DNA-fragmentation and caspase-3-activity after 12, 24 and 48 h. Ellagic acid significantly potentiated the effects of quercetin (at 5 and 10 micro mol/L each) in the reduction of proliferation and viability and the induction of apoptosis. Significant alterations in cell cycle kinetics were also observed. The synergy was confirmed by an isobolographic analysis of the cell proliferation data. The interaction of ellagic acid and quercetin demonstrated an enhanced anticarcinogenic potential of polyphenol combinations, which was not based solely on the additive effect of individual compounds, but rather on synergistic biochemical interactions.

The effects of dietary ellagic acid on rat hepatic and esophageal mucosal cytochromes P450 and phase II enzymes

Ellagic acid (EA), a naturally occurring plant polyphenol possesses broad chemoprotective properties. Dietary EA has been shown to reduce the incidence of N-2-fluorenylacetamide-induced hepatocarcinogenesis in rats and N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumors. In this study changes in the expression and activities of specific rat hepatic and esophageal mucosal cytochromes P450 (P450) and phase II enzymes following dietary EA treatment were investigated. Liver and esophageal mucosal microsomes and cytosol were prepared from three groups of Fisher 344 rats which were fed an AIN-76 diet containing no EA or 0.4 or 4.0 g/kg EA for 23 days. In the liver total P450 content decreased by up to 25% and P450 2E1-catalyzed p-nitrophenol hydroxylation decreased by 15%. No changes were observed in P450 1A1, 2B1 or 3A1/2 expression or activities or cytochrome b5 activity. P450 reductase activity decreased by up to 28%. Microsomal epoxide hydrolase (mEH) expression decreased by up to 85% after EA treatment, but mEH activities did not change. The hepatic phase II enzymes glutathione S-transferase (GST), NAD(P)H:quinone reductase [NAD-(P)H:QR] and UDP glucuronosyltransferase (UDPGT) activities increased by up to 26, 17 and 75% respectively. Assays for specific forms of GST indicated marked increases in the activities of isozymes 2-2 (190%), 4-4 (150%) and 5-5 (82%). In the rat esophageal mucosa only P450 1A1 could be detected by Western blot analysis and androstendione was the only P450 metabolite of testosterone detectable. However, there were no differences in the expression of P450 1A1, the formation of androstendione or NAD(P)H:QR activities between control and EA-fed rats in the esophagus. Although there was no significant decrease in overall GST activity, as measured with 1-chloro-2,4-dinitrobenzene (CDNB), there was a significant decrease in the activity of the 2-2 isozyme (66% of control). In vitro incubations showed that EA at a concentration of 100 microM inhibited P450 2E1, 1A1 and 2B1 activities by 87, 55 and 18% respectively, but did not affect 3A1/2 activity. Using standard steady-state kinetic analyses, EA was shown to be a potent non-competitive inhibitor of both liver microsomal ethoxyresorufin O-deethylase and p-nitrophenol hydroxylase activities, with apparent Ki values of approximately 55 and 14 microM respectively. In conclusion, these results demonstrate that EA causes a decrease in total hepatic P450 with a significant effect on hepatic P450 2E1, increases some hepatic phase II enzyme activities [GST, NAD-(P)H:QR and UDPGT] and decreases hepatic mEH expression. It also inhibits the catalytic activity of some P450 isozymes in vitro. Thus the chemoprotective effect of EA against various chemically induced cancers may involve decreases in the rates of metabolism of these carcinogens by phase I enzymes, due to both direct inhibition of catalytic activity and modulation of gene expression, in addition to effects on the expression of phase II enzymes, thereby enhancing the ability of the target tissues to detoxify the reactive intermediates.

Phytonutrient intake by adults in the United States in relation to fruit and vegetable consumption

BACKGROUND

Individuals consuming diets dense in fruits and vegetables consume an array of phytonutrients as well as recognized nutritional components, including vitamins, minerals, and fiber. There is a growing body of evidence that phytonutrients may play positive roles in health.

OBJECTIVE

The purpose of this research was to estimate usual intakes of nine individual phytonutrients by Americans consuming recommended levels of fruits and vegetables compared to intakes by adults not meeting these recommendations, and to identify contributions of food sources to total phytonutrient intakes. The phytonutrients examined in this study are found predominantly in fruits and vegetables.

DESIGN

Food consumption data from the National Health and Nutrition Examination Surveys 2003-2006 and phytonutrient concentration data from US Department of Agriculture databases and the published literature were used to estimate energy-adjusted usual intakes. Student's t tests were used to compare mean energy-adjusted phytonutrient intakes between subpopulations who consumed recommended amounts of fruits and vegetables vs those who did not. Percentage contributions of each phytonutrient by food source were estimated for all adults.

RESULTS

Energy-adjusted intakes of all phytonutrients other than ellagic acid were considerably higher among both men and women meeting dietary recommendations for fruit and vegetable intakes compared to those not meeting the recommendations; energy-adjusted intakes of ellagic acid were higher only among women meeting vs not meeting the recommendations. For five of the nine phytonutrients (α-carotene, β-cryptoxanthin, lycopene, hesperetin, and ellagic acid), a single food accounted for 64% or more of the total intake of the phytonutrient.

CONCLUSIONS

Energy-adjusted intakes of carotenoids and flavonoids are higher among men and women whose diets conform to dietary guidance for fruits and vegetables. A limited number of foods provide the majority of these phytonutrients. Findings from this research provide important reference information on the phytonutrient contributions of a diet rich in fruits and vegetables.

Pomegranate polyphenols and urolithin A inhibit α-glucosidase, dipeptidyl peptidase-4, lipase, triglyceride accumulation and adipogenesis related genes in 3T3-L1 adipocyte-like cells

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate fruit is considered an antidiabetic medicine in certain systems of traditional medicine. In addition, pomegranate polyphenols are known as powerful antioxidants with beneficial effects such as the reduction of oxidative / inflammatory stress and the increase of protective signalling such as antioxidant enzymes, neurotrophic factors and cytoprotective proteins.

AIM OF THE STUDY

This work evaluates the effects of pomegranate juice, its main polyphenols known as ellagic acid and punicalagin, as well as its main metabolite urolithin A, on physiological and pharmacological targets of metabolic diseases such as obesity and diabetes.

MATERIALS AND METHODS

For this purpose, enzyme inhibition bioassays of lipase, α-glucosidase and dipeptidyl peptidase-4 were carried out in cell-free systems. Similarly, adipocytes derived from 3T3-L1 cells were employed to study the effects of ellagic acid, punicalagin and urolithin A on adipocyte differentiation and triglyceride (TG) accumulation.

RESULTS

Pomegranate juice, ellagic acid, punicalagin and urolithin A were able to inhibit lipase, α-glucosidase and dipeptidyl peptidase-4. Furthermore, all tested compounds but significantly the metabolite urolithin A displayed anti-adipogenic properties in a dose-dependent manner as they significantly reduced TG accumulation and gene expression related to adipocyte formation such as adiponectin, PPARγ, GLUT4, and FABP4 in 3T3-L1 adipocytes.

CONCLUSION

These results may explain from a molecular perspective the beneficial effects and traditional use of pomegranate in the prevention of metabolic-associated disorders such as obesity, diabetes and related complications.

Strawberry processing does not affect the production and urinary excretion of urolithins, ellagic acid metabolites, in humans

The study of fruit and vegetable processing and its effects on the levels of health-promoting constituents and their bioavailability and metabolism is very relevant to understanding the role of these constituents in human health. Strawberry polyphenols, and particularly ellagitannins and ellagic acid, have been associated with the health benefits of this berry for humans. These compounds are transformed into urolithins by the gut microbiota, and these metabolites exert several biological activities that could be responsible for the health effects of strawberries. Processing potentially increases the extraction of ellagitannins from the strawberry achenes and the release of ellagic acid from ellagitannins. It is of interest to evaluate the effect of processing on strawberry ellagitannin microbial metabolism compared with fresh strawberries. This study shows that no significant differences in the production and excretion of urolithins were found between the intake of fresh strawberries and that of a thermally processed strawberry puree containing the same amount of strawberries. Processing increases the amount of free ellagic acid 2.5-fold, but this had no effect on the transformation in urolithins by the gut microbiota or in the excretion of urolithin metabolites (urolithin glucuronides) in urine, showing that the release of ellagic acid from ellagitannins is not a relevant factor affecting the microbial metabolism. All of the volunteers produced urolithin A, but only 3 of 20 volunteers produced and excreted urolithin B. It is confirmed that some volunteers were efficient producers of urolithins, whereas other produced much lower amounts. These results show that processing does not modify the potential health effects of strawberry polyphenols.

Enhanced oral bioavailability and antioxidant profile of ellagic acid by phospholipids

Ellagic acid (EA) has been reported as a potent antioxidant from natural resources with several nutritional benefits. The major disadvantage of this phytoconstituent is its rapid elimination from the body after administration. To overcome this limitation, a novel dietary formulation of EA with phospholipid was developed to investigate the effect of this complex on carbon tetrachloride induced liver damage in rats. The antioxidant activity of the complex (equivalent of EA = 25 and 50 mg/kg of body weight) and free EA (25 and 50 mg/kg of body weight) was evaluated by measuring various enzymes in oxidative stress condition. The complex significantly protected the liver by restoring the activity of superoxide dismutase, catalase and liver glutathione, and thiobarbituric acid reactive substances with respect to the carbon tetrachloride treated group (P < 0.05 and < 0.01). The complex provided better protection to rat liver than free EA at the same dose. The serum concentration of EA obtained from the complex (equivalent to 80 mg/kg of EA) was higher (C(max) = 0.54 microg/mL) than that of pure EA (80 mg/kg) (C(max) = 0.21 microg/mL), and the complex maintained effective concentration for a longer period of time in serum. The experimental outcome highlighted better hepatoprotective activity of the EA complex due to its potential antioxidant property compared with the free EA tested at the same dose level.

Polyphenols inhibit promotional phase of tumorigenesis: relevance of superoxide radicals

Ellagic acid (EA), tannic acid (TA), caffeic acid (CA), and ferulic acid (FA) offer considerable promise as anticarcinogens. The role of these dietary polyphenols was investigated in the promotional phase of carcinogenesis. Topical application of polyphenols simultaneously with phorbol-12-myristate-13-acetate (PMA) or mezerein resulted in significant protection against 7,12-dimethyl-benz[a]anthracene-induced skin tumors in mice. Caffeic acid was the most effective inhibitor of tumor promotion. In vivo and in vitro treatment of murine peritoneal macrophages with the tumor promoters resulted in stimulation of superoxide anion radical formation. Tannic acid, caffeic acid, and ferulic acid were stronger inhibitors of PMA- and mezerein-induced superoxide anion radical than ellagic acid in in vivo and in vitro conditions. Treatment of [1(3)-14C]glycerol- or [methyl-14C]choline chloride-labeled resident or thioglycollate-elicited macrophages with PMA and mezerein led to accumulation of radioactive diacylglycerol equivalents. The polyphenols were capable of inhibiting these releases.

Caffeic acid and ellagic acid ameliorate adjuvant-induced arthritis in rats via targeting inflammatory signals, chitinase-3-like protein-1 and angiogenesis

Rheumatoid arthritis (RA) is a chronic inflammatory arthropathy that principally attacks the joints. The present study aimed to explore the potential anti-arthritic effects of caffeic acid and ellagic acid in adjuvant-induced arthritis, compared to celecoxib. The current study also explored the underlying molecular mechanisms e.g., pro-inflammatory signals including chitinase-3-like protein-1 (CHI3L1); a glycoprotein that correlates with RA joint destruction besides angiogenesis, oxidative stres and apoptosis. Interestingly, caffeic and ellagic acids attenuated the severity of arthritis with comparable efficacy to celecoxib. Both agents effectively mitigated paw edema and inflammatory cell infiltration and protected the joint tissues against pannus formation along with cartilage and bone destruction. Notably, they also lowered the paw expression of NF-κB and the downstream effector CHI3L1 and its synthesis inducer IL-1β. They also lowered the levels of the tissue remodeling factor MMP-9 and the angiogenic signal VEGF in rat paws. Both agents also suppressed serum oxidative stress via diminishing lipid peroxides and nitric oxide together with augmentation of reduced glutathione in arthritic animals. Regarding apoptosis, they attenuated paw caspase-3 levels, favoring cell survival. Together, these favorable findings may advocate the use of caffeic and ellagic acids as adjunct modalities for the management of RA to mitigate joint damage.

Protection against dextran sulfate sodium-induced colitis by microspheres of ellagic acid in rats

Ellagic acid (EA), a naturally occurring plant phenol, has the antioxidant and anti-inflammatory activities. In the present study, we examined the effect of EA contained in microspheres on the ulcerative colitis induced experimentally in rats by dextran sulfate sodium (DSS). Experimental colitis was induced in male Fisher 344 rats by daily treatment with 3% DSS solution in drinking water for 7 days. EA of microspheres (mcEA: 1 approximately 10 mg/kg as EA contents) was administered p.o. twice daily for 6 days. In a preliminary study, we found that these microsphere capsules, when administered p.o., are effectively dissolved in the proximal to the ileo-cecal junction and distributed to the terminal ileum and the colon. The ulceration area, colon length, and mucosal myeloperoxidase (MPO) activity as well as thiobarbituric acid-reactive substances (TBARS) were measured on 7th day after the onset of DSS treatment. The DSS treatment for 7 days caused severe mucosal lesions in the colon, accompanied with the increases of MPO activity and TBARS as well as the decreases of body weight gain and colon length. Administration of mcEA reduced the severity of DSS-induced colitis in a dose-dependent manner, and a significant effect was observed at 10 mg/kg, the ED50 being 2.3 mg/kg. This mcEA treatment also significantly mitigated changes in various biochemical parameters in the colonic mucosa induced by DSS. Although plain EA (without using microspheres) was also effective in reducing the severity of DSS-induced colitis, this effect was much less potent as compared with that of mcEA; the ED50 was about 15 times higher than that of mcEA. In addition, a significant effect on DSS-induced colitis was also obtained by intra-rectal administration of superoxide dismutase, an anti-oxidative agent. These results suggest that EA prevents the ulcerative colitis induced by DSS, probably by radical scavenging and/or anti-oxidative actions. The microspheres used in this study may be useful for delivering an orally administered drug specifically to the colon.

Effects of dietary phenethyl isothiocyanate, ellagic acid, sulindac and calcium on the induction and progression of N-nitrosomethylbenzylamine-induced esophageal carcinogenesis in rats

The potential inhibitory effects of phenethyl isothiocyanate (PEITC), ellagic acid (EA), sulindac and supplemental dietary calcium (SDC) on N-nitrosomethylbenzylamine (NMBA)-induced esophageal carcinogenesis were evaluated in rats utilizing an abbreviated (5 week) NMBA treatment protocol which allowed administration of the putative inhibitors throughout the experiment (i.e. beginning 2 weeks prior to NMBA treatment) or following completion of NMBA dosing only. PEITC at 500 p.p.m. significantly inhibited tumor incidence and multiplicity when given before and during, but not following, NMBA treatment. Neither sulindac at 125 p.p.m. nor SDC (2% versus 0.5% in control diet) inhibited tumor development when given during or following NMBA treatment. EA, which was administered only following NMBA treatment, significantly reduced the incidence (66.7% versus 100% in NMBA controls), but not the multiplicity, of esophageal tumors at the high-dose (4000 p.p.m.) level. Together these findings indicate that: (i) PEITC selectively inhibits the induction but not the subsequent progression of NMBA-induced esophageal tumors; (ii) EA may repress esophageal tumor development when administered following NMBA treatment; (iii) at the doses administered, neither sulindac nor SDC possess significant inhibitory activity against NMBA-induced esophageal carcinogenesis in the rat.

The modulatory effect of ellagic acid and rosmarinic acid on ultraviolet-B-induced cytokine/chemokine gene expression in skin keratinocyte (HaCaT) cells

Ultraviolet radiation (UV) induces an increase in multiple cutaneous inflammatory mediators. Ellagic acid (EA) and rosmarinic acid (RA) are natural anti-inflammatory and immunomodulatory compounds found in many plants, fruits, and nuts. We assessed the ability of EA and RA to modulate IL-1β, IL-6, IL-8, IL-10, MCP-1, and TNF-α gene expression in HaCaT cells after UVB irradiation. Cells were treated with UVB (100 mJ/cm(2)) and simultaneously with EA (5 μM in 0.1% DMSO) or RA (2.7 μM in 0.5% DMSO). Moreover, these substances were added to the UVB-irradiated cells 1 h or 6 h before harvesting, depending on the established UVB-induced cytokine expression peak. Cytokine gene expression was examined using quantitative real time polymerase chain reaction. RA produced a significant reduction in UVB-induced expression of IL-6, IL-8, MCP-1, and TNF-α when applied at the same time as irradiation. EA showed milder effects compared with RA, except for TNF-α. Both substances decreased IL-6 expression, also when applied 5 h after irradiation, and always produced a significant increase in UVB-induced IL-10 expression. Our findings suggest that EA and RA are able to prevent and/or limit the UVB-induced inflammatory cascade, through a reduction in proinflammatory mediators and the enhancement of IL-10, with its protective function.

Effects of Oral Administration of Ellagic Acid-Rich Pomegranate Extract on Ultraviolet-Induced Pigmentation in the Human Skin

We performed a double-blind, placebo-controlled trial to clinically evaluate the protective and ameliorative effects of ellagic acid-rich pomegranate extract on pigmentation in the skin after ultraviolet ray (UV) irradiation, using female subjects in their 20s to 40s. Thirteen healthy volunteers per group were randomly assigned to three groups; namely, high dose (200 mg/d ellagic acid), low dose (100 mg/d ellagic acid) and control (0 mg/d ellagic acid: placebo). Each group received the respective test foods for 4 wk. Each subject received a 1.5 MED (minimum erythema dose) of UV irradiation on an inside region of the right upper arm, based on the MED value measured on the previous day. Luminance (L), melanin and erythema values were measured before the start of the test food intake, and after 1, 2, 3 and 4 wk following the start of the test food intake. Further, questionnaires were conducted regarding the condition of the skin before the start of the test food intake and at the termination of the test food intake. As a result, decreasing rates of L values from the baseline in the low- and high-dose groups were inhibited by 1.35% and 1.73% respectively, as compared to the control group. Further, a stratified analysis using subjects with a slight sunburn revealed an inhibited decrease of L values compared with the control group at 1, 2 (p<0.01, respectively) and 4 wk (p<0.05) after the start of the test food intake in the low-dose group, and at 2 and 3 wk (p<0.05) in the high-dose group. Furthermore, the results of questionnaires showed ameliorating tendencies due to the test food, in some items such as "brightness of the face" and "stains and freckles." Based on the above-mentioned results, it is suggested that ellagic acid-rich pomegranate extract, ingested orally, has an inhibitory effect on a slight pigmentation in the human skin caused by UV irradiation.

Biodistribution of ellagic acid and dose-related inhibition of lung tumorigenesis in A/J mice

Ellagic acid (EA), derived from fruit ellagitannins, is known to be antimutagenic and anticarcinogenic in various animal tumor models. In this study, EA at a dose of 4 g/kg diet inhibited multiplicity of tumors induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mice by 54%. This inhibition was dose related between 0.06 and 4.0 g/kg diet. In contrast, two related compounds, esculin and esculetin, had no effect on lung tumorigenesis. The biodistribution of EA was studied as a function of dose and time after gavage of EA. The levels of EA in the lung were directly proportional to the dose of EA between 0.2 and 2.0 mmol. The maximum level of EA, corresponding to 21.3 nmol/g, was observed 30 minutes after gavage with 2.0 mmol of EA/kg body wt, which corresponds to only 70 ppm of the administered dose. The levels in liver tissues were 10-fold lower and reached a maximum 30 minutes after gavage. At this interval, the blood level of EA was 1 nmol/ml. The inclusion of EA in cyclodextrin doubles the level of EA in lung tissues. These results demonstrate that EA localizes preferentially in lung tissues and confirm that EA administered orally can inhibit lung tumorigenesis.

Anti-inflammatory and antioxidant nanostructured cellulose membranes loaded with phenolic-based ionic liquids for cutaneous application

The utilization of natural compounds, such as phenolic acids and biopolymers, in the healthcare domain is gaining increasing attention. In this study, bacterial nanocellulose (BC) membranes were loaded with ionic liquids (ILs) based on phenolic acids. These ionic compounds, with improved solubility and bioavailability, were prepared by combining the cholinium cation with anions derived from caffeic, ellagic and gallic acids. The obtained BC-ILs membranes were homogeneous, conformable and their swelling ability agreed with the solubility of each IL. These membranes revealed a controlled ILs dissolution rate in the wet state and high antioxidant activity. In vitro assays performed with Raw 264.7 macrophages and HaCaT keratinocytes revealed that these novel BC-ILs membranes are non-cytotoxic and present relevant anti-inflammatory properties. Diffusion studies with Hanson vertical diffusion cells showed a prolonged release profile of the ILs from the BC membranes. Thus, this work, successfully demonstrates the potential of BC-ILs membranes for skin treatment.

The flavonoid ellagic acid from a medicinal herb inhibits host immune tolerance induced by the hepatitis B virus-e antigen

The aim of this study is to characterize the role of ellagic acid, a flavonoid from a medicinal herb which blocks HBeAg secretion in a HBV infected cell line and in HBeAg transgenic mice, in immune tolerance in chronic HBV infection. Using the mouse strain C57ML/6, HBeAg-producing transgenic mice (HBeAg-Tg), under the control of metal ion-inducible promoter were generated. The effect on immune tolerance of HBeAg-Tg and the release of immune tolerance by the inhibitor of HBeAg secretion, ellagic acid, was tested using T/B cell proliferation, HBeAg/HBeAb production, cytotoxic T-lymphocyte (CTL) and cytokine assays. C57ML/6 based HBeAg-producing HBeAg-Tg mice were tolerant to HBeAg at the T and B-cell level, did not produce antibodies to HBeAg in vivo and in vitro, produced minimal levels of cytokines (IL-4 and IFN-gamma) and decreased CTL responses, while feeding mice with ellagic acid (5mg/kg body weight) blocked the immune tolerance caused by HBeAg. Our results suggest that host immune tolerance induced by HBeAg during HBV infection, a viral strategy to guarantee HBV infection, can be overcome by ellagic acid, thus it can be used as a therapeutic for HBV-carriers.

Influence of ellagic acid on antioxidant defense system and lipid peroxidation in mice

Addition of ellagic acid (EA) to liver microsomes of mice resulted in a steady increase in inhibition of NADPH-dependent lipid peroxidation up to 2 mM concentration. The maximum of 70% inhibition of ascorbate-dependent lipid peroxidation was achieved at 1 mM concentration of EA. Feeding of EA significantly increased the levels of reduced glutathione and glutathione reductase in liver and lungs of male and female mice. However, there were no changes in the activities of catalase and superoxide dismutase. On the other hand, microsomes from liver and lungs of EA fed animals showed significantly suppressed NADPH- and ascorbate-dependent lipid peroxidation.

Disposition of the plant phenol ellagic acid in the mouse following oral administration by gavage

1. The absorption, distribution and elimination of 3H-ellagic acid, a putative antimutagen and anticarcinogen, was studied in male Swiss-Webster mice following oral administration. 2. Levels of 3H-ellagic acid were highest in blood 30 min after administration, in urine and bile 120 min post-administration, and in liver, lung and kidney 15 min after administration [corrected]. 3. Free ellagic acid and its conjugates were present in urine, bile and blood. H.p.l.c. analysis of the organic solvent extracts of urine, bile and blood indicated the presence of four metabolites in urine, two in blood and one in bile. 4. Sulphate ester, glucuronide and glutathione conjugates of ellagic acid were present in urine, bile and blood. H.p.l.c. analysis of organic solvent extracts after aryl sulphatase or beta-glucuronidase treatment showed that ellagic acid was the major component present. 5. Absorption of 3H-ellagic acid occurred mostly within two hours after oral administration. Levels in blood, bile and tissues were low and almost all of the absorbed dose was excreted in urine. 6. More than 53% of the orally administered 3H-ellagic acid remained in the gastrointestinal tract at 24 h. Approximately 19% was excreted in faeces and 22% in urine at 24 h. 7. Of the 24 h faecal radioactivity 93% was extractable into organic solvents and more than 80% of this fraction was free ellagic acid. Only one metabolite was found in faeces.

Neuroprotective effects of ellagic acid on cuprizone-induced acute demyelination through limitation of microgliosis, adjustment of CXCL12/IL-17/IL-11 axis and restriction of mature oligodendrocytes apoptosis

CONTEXT

Ellagic acid (EA) is a natural phenol antioxidant with various therapeutic activities. However, the efficacy of EA has not been examined in neuropathologic conditions.

OBJECTIVE

In vivo neuroprotective effects of EA on cuprizone (cup)-induced demyelination were evaluated.

MATERIAL AND METHODS

C57BL/6 J mice were fed with chow containing 0.2% cup for 4 weeks to induce oligodendrocytes (OLGs) depletion predominantly in the corpus callosum (CC). EA was administered at different doses (40 or 80 mg/kg body weight/day/i.p.) from the first day of cup diet. Oligodendrocytes apoptosis [TUNEL assay and myelin oligodendrocyte glycoprotein (MOG+)/caspase-3+ cells), gliosis (H&E staining, glial fibrillary acidic protein (GFAP+) and macrophage-3 (Mac-3+) cells) and inflammatory markers (interleukin 17 (IL-17), interleukin 11 (IL-11) and stromal cell-derived factor 1 α (SDF-1α) or CXCL12] during cup intoxication were examined.

RESULTS

High dose of EA (EA-80) increased mature oligodendrocytes population (MOG+ cells, p < 0.001), and decreased apoptosis (p < 0.05) compared with the cup mice. Treatment with both EA doses did not show any considerable effects on the expression of CXCL12, but significantly down-regulated the expression of IL-17 and up-regulated the expression of IL-11 in mRNA levels compared with the cup mice. Only treatment with EA-80 significantly decreased the population of active macrophage (MAC-3+ cells, p < 0.001) but not reactive astrocytes (GFAP+ cells) compared with the cup mice.

DISCUSSION AND CONCLUSION

In this model, EA-80 effectively reduces lesions via reduction of neuroinflammation and toxic effects of cup on mature OLGs. EA is a suitable therapeutic agent for moderate brain damage in neurodegenerative diseases such as multiple sclerosis.

Combination of blocking agents and suppressing agents in cancer prevention

The design of the present study was based on the premise that if blocking agents and suppressing agents are targeted at different phases of chemical carcinogenesis, a greater chemopreventive effect would be achieved by using the combination treatment compared to the single-agent treatment. The dimethylbenz[a]anthracene (DMBA)-induced mammary tumor model in rats was used to test this hypothesis, with the blocking agent given before DMBA only and the blocking agent given after DMBA until the end of the experiment. A total of three sets of combination treatment were carried out; diallyl sulfide/Se-methylselenocysteine, ellagic acid/selenomethionine, and diallyl sulfide/quercetin. In all three cases, the combination regimen was much more effective than the single-agent treatment in tumor suppression. It should be noted that only naturally occurring inhibitors were selected for these experiments. The impact of minor dietary anutrients in cancer chemoprevention is also discussed.

Ellagic acid, sulforaphane, and ursolic acid in the prevention and therapy of breast cancer: current evidence and future perspectives

Globally, breast cancer is the most common cancer and the second leading cause of cancer-related death among women. Surgery, chemotherapy, hormonal therapy, and radiotherapy are currently available treatment options for breast cancer therapy. However, chemotherapy, hormonal therapy, and radiotherapy are often associated with side effects and multidrug resistance, recurrence, and lack of treatment in metastasis are the major problems in the treatment of breast cancer. Recently, dietary phytochemicals have emerged as advantageous agents for the prevention and therapy of cancer due to their safe nature. Ellagic acid (EA), sulforaphane (SF), and ursolic acid (UA), which are found in widely consumed fruits and vegetables, have been shown to inhibit breast cancer cell proliferation and to induce apoptosis. This review encompasses the role of EA, SF, and UA in the fight against breast cancer. Both in vitro and in vivo effects of these agents are presented.

The dietary polyphenol ellagic acid is a potent inhibitor of hOAT1

Ellagic acid (EA), a polyphenol present in berries, has been demonstrated to be preventive of esophageal and colon cancer in animals. Here, we have studied the ability of organic anion transporters (OATs) and organic anion-transporting polypeptides (OATPs) to transport EA. The accumulation of radiolabeled (14)C]EA, [(3)H]p-aminohippuric acid (PAH), [(14)C]glutarate, [(3)H]estrone sulfate, [(3)H]ochratoxin A, and [(3)H]taurocholic acid +/- inhibitor(s) was tested in OAT- and OATP-expressing oocytes. Oocytes expressing human (h)OAT1, rat (r)Oat1, and hOAT4 accumulated 6.5-, 7.1-, and 8.9-fold more EA, respectively, than did water-injected oocytes. This accumulation was prevented by the prototype OAT inhibitors bromosulfophthalein and probenecid. rOatp1, mouse (m)Oat2, hOAT3, and mOat5 showed no EA transport. The uptake of the prototype OAT substrate PAH in hOAT1-expressing oocytes was dose dependently and potently inhibited by EA with an IC(50)of 207 nM. In conclusion, we have demonstrated that the OAT family members hOAT1, rOat1, and hOAT4 mediate transport of EA, with a very high affinity for hOAT1.

Protective effect of ellagic acid on concanavalin A-induced hepatitis via toll-like receptor and mitogen-activated protein kinase/nuclear factor κB signaling pathways

Ellagic acid (EA) is present in certain fruits and nuts, including raspberries, pomegranates, and walnuts, and has anti-inflammatory and antioxidant properties. The aims of this study were to examine the protective effect of EA on concanavalin A (Con A)-induced hepatitis and to elucidate its underlying molecular mechanisms in mice. Mice were orally administered EA at different doses before the intravenous delivery of Con A; the different experimental groups were as follows: (i) vehicle control, (ii) Con A alone without EA, (iii) EA at 50 mg/kg, (iv) EA at 100 mg/kg, and (v) EA at 200 mg/kg. We found that EA pretreatment significantly reduced the levels of plasma aminotransferase and liver necrosis in Con A-induced hepatitis. Also, EA significantly decreased the expression levels of the toll-like receptor 2 (TLR2) and TLR4 mRNA and protein in liver tissues. Further, EA decreased the phosphorylation of JNK, ERK1/2, and p38. EA-treated groups showed suppressions of nuclear factor κB (NF-κB) and IκB-α degradation levels in liver tissues. In addition, EA pretreatment decreased the expression of pro-inflammatory cytokines, such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β). These results suggest that EA protects against T-cell-mediated hepatitis through TLR and mitogen-activated protein kinase (MAPK)/NF-κB signaling pathways.

Ellagic Acid and Natural Sources of Ellagitannins as Possible Chemopreventive Agents Against Intestinal Tumorigenesis in the Min Mouse

Ellagic acid has been shown to have chemopreventive effects in various experimental cancer models. We wanted to see whether pure ellagic acid and natural ellagitannins from cloudberry (Rubus chamaemorus) seed and pulp have any effect on adenoma formation in Apc-mutated Min mice. From the age of 5 wk, the mice were fed either a control diet, a diet containing pure ellagic acid at 1,564 mg/kg, or diets containing 4.7% (wt/wt) cloudberry seeds or 5.3% cloudberry pulp. The concentrations of ellagitannins and free ellagic acid in the seed diet were 807 and 42 mg/kg and in the pulp diet 820 and 34 mg/kg, respectively. After the 10-wk feeding period, ellagic acid had no effect on the number or size of adenomas in the distal or total small intestine, but it increased adenoma size in the duodenum when compared with the control diet (1.50+/-0.29 vs. 1.16+/-0.31 mm; P=0.029). Neither cloudberry seed nor pulp diets had any effect on the adenoma formation. Chemopreventive effects and mechanisms of whole cloudberry and other similar sources of phenolic compounds should, however, be studied, further taking into account food matrix and interactions with other dietary constituents that may be involved in the bioavailability and metabolism of ellagitannins.