Identification of a hepatoprotective peptide in wheat gluten hydrolysate against D-galactosamine-induced acute hepatitis in rats.

A hepatoprotective peptide, pyroglutamyl leucine (pyroGlu-Leu), was identified in wheat gluten hydrolysate through an in vivo activity-guided fractionation approach based on D-galactosamine-induced acute hepatitis in rats and fractionation of peptides with large-scale preparative ampholine-free isoelectric focusing. The active acidic fraction predominantly consisted of pyroglutamyl peptides and free pyroglutamic acid. Pyroglutamyl peptides were derivatized with phenyl isothiocyanate after removal of a pyroglutamyl residue by pyroglutamate aminopeptidase.

Suppressive effect of modified arabinoxylan from rice bran (MGN-3) on D-galactosamine-induced IL-18 expression and hepatitis in rats.

We investigated in this study the effect of modified arabinoxylan from rice bran (MGN-3) and its fractions on D-galactosamine (D-GalN)-induced IL-18 expression and hepatitis in rats. Male Wistar rats were pretreated with MGN-3 or fractions of the MGN-3 hydrolysate, or with saline 1 h before administering D-GalN (400 mg/kg B.W.

Protection by dietary Spirulina platensis against D-galactosamine--and acetaminophen-induced liver injuries.

Increasing attention has been paid to Spirulina for its potential clinical uses. The present study investigated the protection by dietary Spirulina platensis against d-galactosamine (d-GalN)- and acetaminophen (APAP)-induced hepatitis in ICR mice. Mice in each group (n 6) were fed with a standard diet (American Institute of Nutrition (AIN)-93G), a positive control diet containing 0.

Production of L-tryptophan-derived catabolites in hepatocytes from streptozotocin-induced diabetic rats.

Background: Recently the L-tryptophan (Trp) metabolites such as L-kynurenine(Kyn), L-kinurenic acid, quinolinic acid (QA) and picolinic acid (PA) have been shown physiologically important in central nervous and immune system, and various enzyme activities concerning their production were reported to be affected by insulin-dependent diabetes mellitus. However, the states of these metabolites in diabetes have not been clarified enough yet.

Aim Of Study: The present study was performed to make clear the states of the productions of L-Kyn, QA, PA and nicotinamide (Nam) in vitro in the hepatocytes prepared from streptozotocin (STZ)-induced diabetic rats using [5-3H]L-Trp.

Mechanism of the suppression against D-galactosamine-induced hepatic injury by dietary amino acids in rats.

To elucidate the mechanism by which dietary amino acids suppress the D-galactosamine (D-GalN)-induced hepatitis, we examined the involvement of Kupffer cells, tumor necrosis factor-alpha (TNF-alpha) and apoptosis in the mechanism. In experiment 1, the rats were fed with 10% L-glutamine or 5% glycine diet injected with D-GalN with or without gadolinium chloride (GdCl3)-pretreatment. The results indicated that these amino acids suppressed the D-GalN-induced elevation of serum transaminase activities, irrespective of GdCl3-pretreatment.

L-Gln and L-Ser suppress the D-galactosamine-induced IL-18 expression and hepatitis.

D-Galactosamine (GalN) induces acute hepatitis in experimental animals and this hepatitis has been shown to be suppressed by preceding ingestion of amino acids such as Gly, L-Ser, and L-Gln. However, little is known about the mechanism of its action. The present study shows for the first time that IL-18 reduction is involved in the suppressive actions of L-Gln and L-Ser on GalN-induced hepatitis.

Down-regulation of alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase by polyunsaturated fatty acids in hepatocytes is not mediated by PPARalpha.

Background: alpha-Amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) is a key enzyme in NAD biosynthesis from tryptophan. Dietary polyunsaturated fatty acids (PUFA) have been shown to suppress hepatic ACMSD activity and its mRNA level in rat. However the mechanism of the suppressive action has not been clarified yet.

Effect of dietary fiber in edible seaweeds on the development of D-galactosamine-induced hepatopathy in rats.

Previous studies in our laboratory demonstrated the repressive effect of seaweeds (Laminaria sp., Sargassum fulvellum, Eisenia bicyclis and Gelidium sp.) against D-galactosamine (D-GalN)-induced hepatopathy.

Effects of various kinds of edible seaweeds in diets on the development of D-galactosamine-induced hepatopathy in rats.

In the present study we investigated the effects of 11 kinds of edible seaweeds (6 brown and 5 red algae) which contain characteristic seaweed dietary fibers on the induction of D-GalN (D-galactosamine)-hepatopathy in rats (Exps. 1 and 2). Then, the efficacy of various components prepared from Gelidium sp.

Dietary protein level and dietary interaction affect quinolinic acid concentration in rats.

During tryptophan-niacin conversion, hepatic alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) [EC4.1.1.

Hypocholesterolemic mechanism of Chlorella: Chlorella and its indigestible fraction enhance hepatic cholesterol catabolism through up-regulation of cholesterol 7alpha-hydroxylase in rats.

Chlorella powder (CP) has a hypocholesterolemic effect and high bile acid-binding capacity; however, its effects on hepatic cholesterol metabolism are still unclear. In the present study, male Wistar rats were divided into four groups and fed a high sucrose + 10% lard diet (H), an H + 10% CP diet (H+CP), an H + 0.5% cholesterol + 0.

Roles of nuclear receptors in the up-regulation of hepatic cholesterol 7alpha-hydroxylase by cholestyramine in rats.

Nuclear receptors are involved in regulating the expression of cholesterol 7alpha-hydroxylase (CYP7A1), however, their roles in the up-regulation of CYP7A1 by cholestyramine (CSR) are still unclear. In the present study, male Wistar rats were divided into four groups and fed [high sucrose + 10% lard diet] (H), [H + 3% CSR diet] (H + CSR), [H + 0.5% cholesterol + 0.

Differential effects of pyrazinamide and clofibrate on gene expression of rat hepatic alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase, a key enzyme of the tryptophan-NAD pathway.

Hepatic alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) [EC4.1.1.

Effect of docosahexaenoic acid intake on lipid peroxidation in diabetic rat retina under oxidative stress.

Docosahexaenoic acid (DHA) plays an important role in visual function but has a highly oxidation-prone chemical structure. Therefore, we investigated how dietary DHA affects the generation of lipid peroxides in rat retina under oxidative stress in diabetes with/without vitamin E (VE) deficiency. Streptozotocin-induced (50 mg i.

Effects of dietary corn bran hemicellulose and neomycin on hepatic caspase-3 activity and glycoprotein concentration in rats treated with or without D-galactosamine.

The effects of dietary corn bran hemicellulose (CBH) and neomycin (Neo) on hepatic caspase-3 activity and glycoprotein concentration were investigated to explore the possible mechanism of the alleviative action of dietary CBH and Neo on the development of D-galactosamine (GalN)-hepatitis. Rats were fed a diet containing 5% CBH with or without neomycin (Neo) for 7 or 14 d. On the last day of feeding, the rats were treated with GalN (400 mg/kg body weight, i.

Tryptophan-niacin metabolism in rat with puromycin aminonucleoside-induced nephrosis.

We investigated the change of tryptophan-niacin metabolism in rats with puromycin aminonucleoside PAN-induced nephrosis, the mechanisms responsible for their change of urinary excretion of nicotinamide and its metabolites, and the role of the kidney in tryptophan-niacin conversion. PAN-treated rats were intraperitoneally injected once with a 1.0% (w/v) solution of PAN at a dose of 100 mg/kg body weight.

Suppressive effect of corn bran hemicellulose on liver injury induced by D-galactosamine in rats.

Objective: It is well known that the indigestible oligo- and polysaccharides including dietary fiber are important food components and that they have many physiologic functions. This study examined the effect of water-soluble corn bran hemicellulose (CBH) on the development of D-galactosamine (GalN) hepatitis in rats to obtain some knowledge about new functions of dietary fiber.

Methods: Male Wistar rats were fed diets containing 5% CBH for various days (1 to 14 d).

Phenolic antioxidants richly contained in corn bran are slightly bioavailable in rats.

Phenolic acids (PAs) have been shown to be beneficial to human health and are found most abundantly in corn bran ( approximately 4%, w/w), one of the main dietary fibers. This study therefore evaluated the bioavailabilities of phenolic antioxidants ferulic acid (FA) and p-coumaric acid (PCA) in refined corn bran (RCB) by determining their recovery in the plasma, urine, and feces of rats fed a single meal of a RCB diet containing 5% RCB or adapted to the RCB diet for 10 days. In both studies, 0.

Differential effects of dietary fatty acids on rat liver alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase activity and gene expression.

Hepatic alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD; formerly termed picolinic carboxylase) [EC4.1.1.

Ferulic acid is quickly absorbed from rat stomach as the free form and then conjugated mainly in liver.

Ferulic acid (FA) is one of the most abundant phenolic antioxidants in the human diet. Many studies have documented its beneficial properties. It is therefore essential to understand the absorption and metabolism of FA in detail.

Dietary linoleic acid suppresses gene expression of rat liver alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) and increases quinolinic acid in serum.

Hepatic ACMSD [EC4.1.1.

Identification and expression of alpha cDNA encoding human 2-amino-3-carboxymuconate-6-semialdehyde decarboxylase (ACMSD): a key enzyme for the tryptophan-niacine pathway and quinolinate hypothesis.

Quinolinate (quinolinic acid) is a potent endogenous excitotoxin of neuronal cells. Elevation of quinolinate levels in the brain has been implicated in the pathogenesis of various neurodegenerative disorders, the so-called "quinolinate hypothesis." Quinolinate is non-enzymatically derived from 2-amino-3-carboxymuconate-6-semialdehyde (ACMS).

Purification and characterization of a feruloyl esterase from the intestinal bacterium Lactobacillus acidophilus.

Dietary ferulic acid (FA), a significant antioxidant substance, is currently the subject of extensive research. FA in cereals exists mainly as feruloylated sugar ester. To release FA from food matrices, it is necessary to cleave ester cross-linking by feruloyl esterase (FAE) (hydroxycinnamoyl esterase; EC 3.

Digestion and absorption of ferulic acid sugar esters in rat gastrointestinal tract.

We estimated the absorption site and absorptivity of ferulic acid (FA) and its sugar esters, namely 5-O-feruloyl-l-arabinofuranose (FAA) and feruloyl-arabinoxylan (FAXn), in rats on the basis of their recovery in intestinal content and feces by comparing the values with those of a nonabsorbable marker, poly R-478. The results indicated that free FA was absorbed almost completely before reaching cecum. About 40% of dietary FAA was absorbed in rat foregut and 57% disappeared in the cecum.

Ferulic acid sugar esters are recovered in rat plasma and urine mainly as the sulfoglucuronide of ferulic acid.

Ferulic acid sugar esters, the common form of ferulic acid (FA) in cereals, show a stronger antioxidant potential than FA in vitro. However, there is little information on their metabolism and excretion in vivo. In the present study, we investigated the metabolic derivatives of FA in the plasma, urine and feces of rats administered 70 micro mol/kg body of 5-O-feruloyl-L-arabinofuranose (FAA), feruloyl-arabinoxylan (FAXn) or the same molar amount of FA as a comparison.