江頭 祐嘉合

Abstract UV-irradiated red perilla demonstrated promising protective effects against carbon tetrachloride-induced liver injury in mice. UV exposure significantly enhanced the accumulation of rosmarinic acid, malonylshisonin and shisonin in red perilla, and increased DPPH radical scavenging capacity. The hepatoprotective effect of UV-irradiated red perilla may be attributed to the high level of its polyphenolic compounds, which exhibit antioxidant activity.

Aims: Food-derived peptides have been reported to yield a variety of health promoting activities. Pyroglutamyl peptides are contained in the wheat gluten hydrolysate. In the present study, we investigated the effect of pyroglutamyl dipeptides on the lipopolysaccharide (LPS)-induced inflammation in macrophages. Main methods: RAW 264.7 macrophages were treated with LPS and various concentrations of pyroglutamyl-leucine (pyroGlu-Leu), -valine (pyroGlu-Val), -methionine (pyroGlu-Met), and -phenylalanine (pyroGlu-Phe). Cell viability/proliferation and various inflammatory parameters were measured by the established methods including ELISA and western blotting. The binding of fluorescein isothiocyanate-labeled LPS to RAW 264.7 cells was also measured fluorescently. Key findings: All the tested dipeptides significantly inhibited the secretion of nitric oxide, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 from LPS-stimulated RAW 264.7 macrophages. Above all, pyroGlu-Leu inhibited the secretion of all these inflammatory mediators even at the lowest dose (200 mu g/ml). PyroGlu-Leu dose-dependently suppressed I kappa B alpha degradation and MAPK (JNK, ERK, and p38) phosphorylation in LPS-stimulated RAW 264.7 cells. On the other hand, it did not affect the binding of LPS to the cell surface. Significance: Our results indicated that pyroGlu-Leu inhibits LPS-induced inflammatory response via the blocking of NF-kappa B and MAPK pathways in RAW 264.7 macrophages. (C) 2014 Elsevier Inc. All rights reserved.

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. The derivatives were purified by reversed-phase HPLC and subjected to sequence analysis. The active fraction contained pyroGlu-Ile, pyroGlu-Leu, pyroGlu-Gln, pyroGlu-Gln-Gln, and free pyroGlu. Ingestion of pyroGlu-Leu at 20 mg/kg body weight significantly decreased serum aspartate and alanine aminotransferases to approximately 30% and 20% of those values of the vehicle group, respectively, which were near the normal levels. Thirty minutes after ingestion of pyroGlu-Leu at 20 mg/kg, the concentration of pyroGlu-Leu in portal blood plasma increased to approximately 2 mu M.

Psyllium, a dietary fibre rich in soluble components, has both cholesterol- and TAG-lowering effects. Many studies have verified these actions using liver samples, whereas little information is available on the effects of psyllium treatment on other organs. The purpose of the present study was to evaluate the possible beneficial effects of psyllium. We investigated the gene expression profiles of both liver and skeletal muscle using DNA microarrays. C57BL/6J mice were fed a low-fat diet (LFD; 7% fat), a high-fat diet (HFD; 40% fat) or a HFD with psyllium (40% fat+5% psyllium; HFD+Psy) for 10 weeks. Body weights and food intake were measured weekly. After 10 weeks, the mice were killed and tissues were collected. Adipose tissues were weighed, and plasma total cholesterol and TAG blood glucose levels were measured. The expression levels of genes involved in glycolysis, gluconeogenesis, glucose transport and fatty acid metabolism were measured by DNA microarray in the liver and skeletal muscle. In the HFD+Psy group, plasma total cholesterol, TAG and blood glucose levels significantly decreased. There was a significant reduction in the relative weight of the epididymal and retroperitoneal fat tissue depots in mice fed the HFD+Psy. The expression levels of genes involved in fatty acid oxidation and lipid transport were significantly up-regulated in the skeletal muscle of the HFD+Psy group. This result suggests that psyllium stimulates lipid transport and fatty acid oxidation in the muscle. In conclusion, the present study demonstrates that psyllium can promote lipid consumption in the skeletal muscle; and this effect would create a slightly insufficient glucose state in the liver.

Benifuuki contains unique methylated catechins such as epigallocatechin- 3- O-(3 -O-methyl) gallate (EGCG Me). The hot-water extract of Benifuuki (BE) is an ingredient useful for food industrial applications. In this study, we evaluated the suppressive effect of BE on postprandial hypertriglyceridemia in rats. Rats were fed CE-2 diet for 1 week and deprived of food overnight. A solution containing corn oil (1 mL/head) and BE (50 or 100 mg/head) was given orally. Corn oil (1 mL/head) was given in the control group. Blood was withdrawn via the jugular vein after administration. After the separation of plasma, triglyceride was measured. Increase of plasma triacylglycerol after the administration of corn oil in rats was delayed by BE. The area under the curve (AUC) of plasma triglycerides was significantly decreased (by 43%) in the 100 mg per head BE group, as compared with the control group. BE suppressed postprandial hypertriglyceridemia, which is a risk factor for coronary heart disease. These results suggest that BE may help to prevent postprandial hypertriglyceridemia.

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.). The serum transaminase activities, IL-18 mRNA expression level in the liver and IL-18 concentration in the serum were determined 24 h after injecting D-GalN. Both the oral and intraperitoneal administration of MGN-3 (20 mg/kg B.W.) alleviated D-GalN-induced hepatic injury under these experimental conditions. The low-molecular-weight fraction (LMW) of MGN-3 showed the strongest protective effect on D-GalN-induced liver injury, its main sugar component being glucose. Moreover, the D-GalN-induced IL-18 expression was significantly reduced by treating with MGN-3 and LMW. The results suggest that MGN-3 and LMW could provide significant protection against D-GalN liver injury, and that IL-18 might be involved in their protective influence.

Water spinach (Ipomoea aquatica Forsk; I. aquatica) of the green-stemmed type (green type) is widely consumed, but there also exists a red-stemmed variety (red type). In the present study, the antioxidant capacity of the red type was compared to that of the green type in carbon tetrachloride (CCl4)-treated mice. CCl4-induced thiobarbituric acid reactive substrate (TBARS) formation in the liver was significantly suppressed in mice fed 5% red-type I. aquatica, while the green type showed no effect. Hydrophobic oxygen radical absorbance capacity (H-ORAC(FL)) in the red type showed a lower level than that in the green type: however, lipophilic ORAC (L-ORAC(FL)) and total-ORAC(FL) levels were significantly higher in the red type than in the green type. alpha-Tocopherol, anthocyanidin/proanthocyanidin, and beta-carotene contents were all significantly higher in the red type than in the green type. These results suggest that the wild red-type I. aquatica contains certain lipophilic components that exert antioxidant capacities not only in vitro but also in vivo. Such effective components in the red type would be beneficial phytochemicals for suppressing several diseases related to oxidative stress.

Hepatic α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) plays a key role in regulating NAD biosynthesis. In normal rats, ACMSD has been generally detectable only in the liver and kidneys. Therefore, there is a possibility that liver or kidney injury affects tryptophan-niacin metabolism. We previously reported the significant change of tryptophan-niacin metabolism in rats with liver cirrhosis or in rats with d-galactosamine injected liver injury. In this experiment, we investigated the change of tryptophan-niacin metabolism in rats treated 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. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. The reduction of urinary excretion of niacin in nephrotic rats may be due to the reduction of blood tryptophan concentration. The role of the kidney ACMSD may be insignificant concerning tryptophan-niacin conversion under this experimental condition. © 2006 Elsevier B.V. All rights reserved.

Hepatic alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylate (ACMSD) [EC4.1.1.45] plays a key role in regulating NAD biosynthesis from tryptophan. The aim of this study was to evaluate the ACMSD mRNA expression after pyrazinamide or peroxisome proliferators ingestion. When rats were fed a control (pyrazinamide- and clofibrate-free) diet, 1% pyrazinamide- or 0.24% clofibrate-containing diets for 8 days, hepatic ACMSD activity and mRNA in rats consuming the clofibrate-containing diet was strongly suppressed, as compared with those fed the control and pyrazinamide diet. Pyrazinamide suppressed liver and kidney ACMSD activities, but did not affect ACMSD mRNA. Blood NAD was increased in the colfibrate and pyrazinamide groups. Shifting from the control diet to a clofibrate diet suppressed ACMSD mRNA strongly at day 1 and continued through day 4. However ACMSD activity decreased gradually. In rats fed with several kind of perozisome-proliferator-containing diets such as phthalate ester, bezafibrate, Wy-14,643, 2-(-4-chlorophenoxy) propionic acid, or dehydroisoandrosterone for 8 days, hepatic ACMSD mRNA was drastically decreased by all the peroxisome proliferators. These results suggest that the transcription level of hepatic ACMSD is modulated by peroxisome proliferators, and the fluctuation of the hepatic ACMSD mRNA expression was followed by that of the ACMSD activity. However, pyrazinamide does not affect the transcription level of hepatic ACMSD.

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. The collection of 24-hour urine was conducted 8 days after PAN injection. Daily urinary excretion of nicotinamide and its metabolites, liver and blood NAD, and key enzyme activities of tryptophan-niacin metabolism were determined. In PAN-treated rats, the sum of urinary excretion of nicotinamide and its metabolites was significantly lower compared with controls. The kidney alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) activity in the PAN-treated group was significantly decreased by 50%, compared with the control group. Although kidney ACMSD activity was reduced, the conversion of tryptophan to niacin tended to be lower in the PAN-treated rats. A decrease in urinary excretion of niacin and the conversion of tryptophan to niacin in nephrotic rats may contribute to a low level of blood tryptophan. The role of kidney ACMSD activity may be minimal concerning tryptophan-niacin conversion under this experimental condition.

Many studies have been reported that dietary wheat bran, cellulose, resistant starch and inulin suppressed experimental colon tumors or cancer in rats. Dietary fiber reduces contact between the intestinal contents and mucosa, and leads to production of short-chain fatty acids, acetate, propionate, and butyrate, which reduce pH and the conversion of primary to secondary bile acids. Butyrate is the major source of energy for the distal colon and it reduces cell proliferation and induces apoptosis, factors that are associated with inhibition of the transformation of the colonic epithelium to carcinoma. On the other hand, dietary fiber is thought to protect against colorectal cancer in human but this view has been challenged by recent cohort studies that showed no protective effect.