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Junji Terao

Publications and source records attributed to Junji Terao.

At least 37 records · Page 2Linked to original sources
PubMed2005

Effects of forced swimming stress on rat brain function.

Chronic stress has been reported to be an essential factor for depression. In this study, the effect of forced swimming stress on neurotransmitters and cellular signaling pathway contributing to brain functions was investigated using the forced swimming test (FST) in order to understanding of mechanisms to regulate stress signals in brain. Antidepressant drug, imipramine, significantly reduced the immobility time of male rats in the FST by 85% at a dose of 15 mg/kg for 2 weeks. This result indicated that the swimming stress caused a depressed state in the rats without administration of imipramine. Swimming stress significantly lowered the serotonergic ratio and also markedly enhanced the phosphorylation of ERK1/2 in the hypothalamus region compared to the rats without FST. These phenomena may be included in key mechanisms of the development of depression.

Animals↗
PubMed2004

Participation of singlet oxygen in ultraviolet-a-induced lipid peroxidation in mouse skin and its inhibition by dietary beta-carotene: an ex vivo study.

Dietary beta-carotene acts as a photoprotective agent in the skin, but the exact mechanism of protection is unknown. This ex vivo study is focused on determining the mechanism of action of beta-carotene against UV-A-induced skin damage by characterizing peroxidized phosphatidylcholine (PC) and beta-carotene oxidation products. BALB/c mice were fed with basal or a beta-carotene-supplemented diet, and homogenates from their dorsal skin were prepared after 3 weeks for UV-A irradiation. Analyses revealed that the degree of lipid peroxidation in the beta-carotene group was significantly lower than that in the controls. The isomeric composition of hydroperoxy fatty acids, constituting peroxidized PC, was determined by thin-layer chromatography-blotting followed by gas chromatography/mass spectrometry (MS)/selected ion monitoring analysis. The 9- and 10-isomers of peroxidized PC, resulting from the reaction of singlet molecular oxygen ((1)O(2)) with oleic acid, were elevated in the UV-A-exposed control group compared to the experimental group. Similar results were obtained from methylene-blue-sensitized photooxidation of mouse skin lipids in vitro. Liquid chromatography/MS analysis of the homogenates confirmed the formation of beta-carotene 5,8-endoperoxide, a specific marker for the (1)O(2) reaction. These results indicate that dietary beta-carotene accumulates in the skin and acts as a protective agent against UV-A-induced oxidative damage, by quenching the (1)O(2).

Animals↗
PubMed2004

Orally administered rosmarinic acid is present as the conjugated and/or methylated forms in plasma, and is degraded and metabolized to conjugated forms of caffeic acid, ferulic acid and m-coumaric acid.

Rosmarinic acid (RA) is contained in various Lamiaceae herbs used commonly as culinary herbs. Although RA has various potent physiological actions, little is known on its bioavailability. We therefore investigated the absorption and metabolism of orally administered RA in rats. After being deprived of food for 12 h, RA (50 mg/kg body weight) or deionized water was administered orally to rats. Blood samples were collected from a cannula inserted in the femoral artery before and at designated time intervals after administration of RA. Urine excreted within 0 to 8 h and 8 to 18 h post-administration was also collected. RA and its related metabolites in plasma and urine were measured by LC-MS after treatment with sulfatase and/or beta-glucuronidase. RA, mono-methylated RA (methyl-RA) and m-coumaric acid (COA) were detected in plasma, with peak concentrations being reached at 0.5, 1 and 8 h after RA administration, respectively. RA, methyl-RA, caffeic acid (CAA), ferulic acid (FA) and COA were detected in urine after RA administration. These components in plasma and urine were present predominantly as conjugated forms such as glucuronide or sulfate. The percentage of the original oral dose of RA excreted in the urine within 18 h of administration as free and conjugated forms was 0.44 +/- 0.21% for RA, 1.60 +/- 0.74% for methyl-RA, 1.06 +/- 0.35% for CAA, 1.70 +/- 0.45% for FA and 0.67 +/- 0.29% for COA. Approximately 83% of the total amount of these metabolites was excreted in the period 8 to 18 h after RA administration. These results suggest that RA was absorbed and metabolized as conjugated and/or methylated forms, and that the majority of RA absorbed was degraded into conjugated and/or methylated forms of CAA, FA and COA before being excreted gradually in the urine.

Administration, Oral↗
PubMed2004

Quercetin-4'-glucoside is more potent than quercetin-3-glucoside in protection of rat intestinal mucosa homogenates against iron ion-induced lipid peroxidation.

Quercetin is a typical antioxidative flavonoid found in vegetables, which is more commonly present as its glucosides, quercetin-3-glucoside (Q3G) and quercetin-4'-glucoside (Q4'G). The main aim of this study was to estimate the antioxidant activity of Q3G and Q4'G on iron ion-driven lipid peroxidation of the gastrointestinal mucosa. Q4'G markedly suppressed the lipid peroxidation when rat gastrointestinal mucosa homogenates were incubated with Fe(NO3)3 and ascorbic acid. Its effectiveness was greater as compared to that of Q3G and comparable to that of quercetin aglycone. Furthermore, Q4'G yielded higher amounts of quercetin aglycone than Q3G on incubation with the homogenates. However, Q4'G showed a lower chelating activity in comparison to Q3G. These results indicate that Q4'G, even though it has a low chelating activity, because of its efficient conversion to antioxidative aglycone on exposure to the mucosa, can act as a powerful antioxidant on iron ion driven lipid peroxidation in the intestinal mucosa. Thus, vegetables rich in Q4'G, such as onion, are likely to serve as favorable antioxidant sources for suppressing iron-induced oxidative stress in the intestinal tract.

Animals↗
PubMed2004

Absorption, metabolism, degradation and urinary excretion of rosmarinic acid after intake of Perilla frutescens extract in humans.

BACKGROUND: Rosmarinic acid (RA) is a natural polyphenolic substance contained in many Lamiaceae herbs such as Perilla frutescens. Previous studies have shown RA has antioxidative and anti-inflammatory activity. However, little is known on the absorption, metabolism, degradation and excretion of RA. AIM OF THE STUDY: The aim of this study in healthy humans was to determine the absorption, metabolism, and urinary excretion of RA after a single intake of perilla extract (PE). METHOD: Six healthy men (mean age 37.2 +/- 6.2 y and mean body mass index 22.0 +/- 1.9 kg/m(2)) were enrolled in the study that was a crossover design involving single intakes of PE containing 200 mg RA and placebo with a 10 day interval between treatments. Blood samples were collected before intake and at designated time intervals, while urine samples were collected over the periods 0-6 h, 6-24 h and 24-48 h after intake. RA and its related metabolites in plasma and urine were measured by LC-MS. RESULTS: RA, methylated RA (methyl-RA), caffeic acid (CAA), ferulic acid (FA) and a trace of m-coumaric acid (COA) were detected in the urine after intake of PE. In plasma, RA, methyl-RA and FA were detected, with maximum levels obtained 0.5, 2 and 0.5 h after intake of PE, respectively. The majority of these components in both plasma and urine were present as conjugated forms (glucuronide and/or sulfated). The proportion of RA and its related metabolites excreted in the urine was 6.3 +/- 2.2% of the total dose, with approximately 75% of these components being excreted within 6 h after intake of PE. CONCLUSIONS: RA contained in PE was absorbed, conjugated and methylated following intake, with a small proportion of RA being degraded into various components, such as conjugated forms of CAA, FA and COA. These metabolites were then rapidly excreted in the urine.

Adult↗
PubMed2004

Effect of quercetin conjugates on vascular permeability and expression of adhesion molecules.

Quercetin and its glucosides exist in plant foods and are recovered in human plasma as glucuronide and sulfate conjugates. Quercetin and its conjugates show antioxidant activity in model experiments. It remains obscure, however, whether these conjugates retain these biological functions in vivo. We investigated the interaction of quercetin conjugates with lipid bilayers using liposome systems. Less quercetin conjugate was incorporated into liposomes than quercetin aglycone. We also studied the vascular permeability of quercetin-3-glucuronide using cell culture inserts. Incubation of human aortic endothelial cells (HAECs) with IL-1alpha resulted in increased permeability of quercetin-3-glucuronide. Furthermore, quercetin-3-glucuronide showed no suppressive effect on TNF-alpha-induced cell expression of intercellular adhesion molecule-1 (ICAM-1) on HAECs. These observations suggest that circulating conjugates of quercetin pass through the endothelium to reach vascular smooth muscle cells and exert their biological effects in the blood vessels during inflammation followed by deconjugation of the conjugates.

Aorta↗
PubMed2004

In vitro antioxidative activity of (-)-epicatechin glucuronide metabolites present in human and rat plasma.

Recently we identified four conjugated glucuronide metabolites of epicatechin, (-)-epicatechin-3'-O-glucuronide (E3'G), 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide (4'ME3'G), (-)-epicatechin-7-O-glucuronide (E7G) and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide (3'ME7G) from plasma and urine. E3'G and 4'ME3'G were isolated from human urine, while E7G and 3'ME7G were isolated from rats that had received oral administration of (-)-epicatechin (Natsume et al. (2003), Free Radic. Biol. Med. 34,840-849). It has been suggested that these metabolites possess considerable in vivo activity, and therefore we carried out a study to compare the antioxidant activities of the metabolites with that of the parent compound. This was achieved by measuring superoxide scavenging activity, reduction of plasma TBARS production and reduced susceptibility of low-density-lipoprotein (LDL) to oxidation. (-)-Epicatechin was found to have more potent antioxidant activity than the conjugated glucuronide metabolites. Both (-)-epicatechin and E7G had marked antioxidative properties with respect to superoxide radical scavenging activity, plasma oxidation induced by 2,2'-azobis-(2-aminopropane) dihydrochloride (AAPH) and LDL oxidation induced by copper ions or 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (MeO-AMVN). In contrast, the other metabolites had light antioxidative activities over the range of physiological concentrations found in plasma.

Animals↗
PubMed2004

Stress control and human nutrition.

Stress is a pervasive factor in everyday life that critically affects development and functioning. Severe and prolonged stress exposure impairs homeostatic mechanisms, particularly associated with the onset of depressive illness. Brain food is aimed at preventing as well as treating a growing number of stress-related mental disorders. Some topics on the association of stress and nutrition is reviewed. (1) An increased activity of serotonergic neurons in the brain is an established consequence of stress. An increase in brain tryptophan levels on the order of that produced by eating a carbohydrate-rich/protein-poor meal causes parallel increases in the amounts of serotonin released into synapses. (2) Eating is thought to be suppressed during stress, due to anorectic effects of corticotrophin releasing hormone, and increased during recovery from stress, due to appetite stimulating effects of residual cortisol. (3) A strong inverse association between coffee intake and risk of suicide. (4) Night eating syndrome has been found to occur during periods of stress and is associated with poor results at attempts to lose weight and disturbances in the hypothalamic-pituitary-adrenal axis. (5) Dietary antioxidants present in fruits and vegetables may improve cognitive function. Therefore, it is concluded that the establishment of functional foods that correctly regulate stress response must be firmly based upon scientific knowledge and legal regulation.

Antioxidants↗
PubMed2003

Antioxidative flavonoid quercetin: implication of its intestinal absorption and metabolism.

Quercetin is a typical flavonoid ubiquitously present in fruits and vegetables, and its antioxidant effect is implied to be helpful for human health. The bioavailability of quercetin glycosides should be clarified, because dietary quercetin is mostly present as its glycoside form. Although quercetin glycosides are subject to deglycosidation by enterobacteria for the absorption at large intestine, small intestine acts as an effective absorption site for glucose-bound glycosides (quercertin glucosides). This is because small intestinal cells possess a glucoside-hydrolyzing activity and their glucose transport system is capable of participating in the glucoside absorption. A study using a cultured cell model for intestinal absorption explains that the hydrolysis of the glucosides accelerates their absorption in the small intestine. Small intestine is also recognized as the site for metabolic conversion of quercetin and other flavonoids as it possesses enzymatic activity of glucuronidation and sulfation. Modulation of the intestinal absorption and metabolism may be beneficial for regulating the biological effects of dietary quercetin.

Animals↗
PubMed2003

Structures of (-)-epicatechin glucuronide identified from plasma and urine after oral ingestion of (-)-epicatechin: differences between human and rat.

(-)-epicatechin is one of the most potent antioxidants present in the human diet. Particularly high levels are found in black tea, apples, and chocolate. High intake of catechins has been associated with reduced risk of cardiovascular diseases. There have been several reports concerning the bioavailability of catechins, however, the chemical structure of (-)-epicatechin metabolites in blood, tissues, and urine remains unclear. In the present study, we purified and elucidated the chemical structure of (-)-epicatechin metabolites in human and rat urine after oral administration. Three metabolites were purified from human urine including (-)-epicatechin-3'-O-glucuronide, 4'-O-methyl-(-)-epicatechin-3'-O-glucuronide, and 4'-O-methyl-(-)-epicatechin-5 or 7-O-glucuronide, according to 1H- and 13C-NMR, HMBC, and LC-MS analyses. The metabolites purified from rat urine were 3'-O-methyl-(-)-epicatechin, (-)-epicatechin-7-O-glucuronide, and 3'-O-methyl-(-)-epicatechin-7-O-glucuronide. These compounds were also detected in the blood of humans and rats by LC-MS. The presence of these metabolites in blood and urine suggests that catechins are metabolized and circulated in the body after administration of catechin-containing foods.

Administration, Oral↗
PubMed2003

Phospholipid hydroperoxides are detoxified by phospholipase A2 and GSH peroxidase in rat gastric mucosa.

The aim of this study was to determine the metabolic fate of phospholipid hydroperoxides (PLOOH) in rat gastric mucosa. Here we report evidence concerning the mechanism for PLOOH detoxification in gastric mucosa homogenate. Analysis by the TLC blot technique showed that the gastric mucosa has the highest potential to eliminate 1-palmitoyl-2-linoleoyl-phosphatidylcholine hydroperoxides (PL-PtdChoOOH) compared with the intestinal mucosa and liver. Major products detected after incubation with gastric mucosa were the partially reduced linoleic acid hydroperoxides (LAOOH) and lysophosphatidylcholine, indicating the involvement of phospholipase A2 (PLA2) in the elimination pathway. Using unilamellar vesicles, we demonstrated that gastric mucosal PLA2 does not distinguish between PLOOH and intact phospholipids. Although gastric mucosal PLA2 activity efficiently eliminated excess amounts of PLOOH, the complete reduction of LAOOH was dependent on the supply of exogenous GSH. In a separate experiment, administration of egg yolk PtdChoOOH to rats for 6 d significantly elevated GSH peroxidase (GPx) activity in the gastric mucosa. We concluded that excess amounts of PLOOH are efficiently eliminated through the hydrolysis by PLA2, and the subsequent reduction of FA hydroperoxide by GPx is the critical step for complete detoxification of oxidized phospholipids in the stomach.

Animals↗
PubMed2003

Inhibition of myeloperoxidase-catalyzed tyrosylation by phenolic antioxidants in vitro.

We have developed an in vitro assay system for the evaluation of the inhibitory effects of phenolic antioxidants on myeloperoxidase (MPO) activity. The formation of dityrosine from the MPO/H2O2/L-tyrosine system was used as an indicator of the MPO activity. Because the buffer system used does not include chloride ion, this assay has the advantage of exclusion of direct reaction between an antioxidant and HOCl. In this assay, ferulic acid, gallic acid, and quercetin strongly inhibited the dityrosine formation, and curcumin and caffeic acid were also effective.

Antioxidants↗
PubMed2003

Inhibition of immunoglobulin E production in allergic model mice by supplementation with vitamin E and beta-carotene.

A diet containing different amounts of vitamin E (alpha-tocopherol; 0.5 mg, 5 mg, 10 mg or 50 mg per 100 g diet) was supplemented to BALB/c mice for 6 weeks. These mice were subcutaneously immunized twice with ovalbumin (OVA). A passive cutaneous anaphylaxis (PCA) analysis demonstrated that the mice fed on the diet containing 5 mg of vitamin E produced the highest level of the OVA-specific immunoglobulin E (IgE) antibody. A lower level of serum IgE was found in the mice supplemented with 0.5 mg, 10 mg and 50 mg of vitamin E. A sandwich ELISA analysis showed that the pattern of the total IgE antibody level among these four groups was the same as that of the allergen-specific IgE. In a separate experiment, 5 mg of vitamin E and/or 50 mg of beta-carotene was supplemented to the basal diet containing vitamin E as alpha-tocopherol acetate (5 mg) in order to evaluate the effect of their combination on OVA-specific and total IgE production in the mice. The supplementation with beta-carotene alone had no effect on OVA-specific or total IgE production. In contrast, supplementation with vitamin E plus beta-carotene effectively suppressed both the antigen-specific and total IgE antibodies. The serum vitamin E and beta-carotene levels were increased by supplementation with the respective compounds. These results strongly suggest that the combination of dietary vitamin E and beta-carotene suppressed IgE production and would therefore help to prevent the type-I allergic reaction.

Animals↗
PubMed2003

Enhancing effect of lipids and emulsifiers on the accumulation of quercetin metabolites in blood plasma after the short-term ingestion of onion by rats.

The effects of co-ingested lipids and emulsifiers on the accumulation of quercetin metabolites in blood plasma after the short-term ingestion of onion by rats were investigated. Plasma extracts of rats that had been fed onion-containing diets for one and two weeks were analyzed by HPLC with electrochemical detection after a treatment with sulfatase/beta-glucuronidase. Almost all of the quercetin metabolites in the plasma were sulfate/glucuronide conjugates of quercetin and isorhamnetin. More than 4.6% (w/w) of soybean oil in the diets significantly enhanced the accumulation of quercetin metabolites in the plasma. Fish oil and beef tallow increased this to an extent similar to that with soybean oil, and lecithin was more effective than the other three lipids. Two emulsifiers, sodium caseinate and sucrose fatty acid ester, also showed an enhancing effect on the accumulation of quercetin metabolites. These results indicate that co-ingested lipids and emulsifiers could enhance the bioavailability of quercetin glucosides in onion.

Animals↗
PubMed2003

Alum augments the experimental allergenicity of Kunitz-type soybean trypsin inhibitor independent of the antigen-adsorption.

In order to inspect the significance of the adsorbing property in the adjuvant activity to enhance IgE production, we immunized BALB/c mice against Kunitz-type soybean trypsin inhibitor (KSTI), the most potent experimental allergen among soybean proteins, associated with Aluminum hydroxide (alum) or DEAE-Sephadex particles. The production of immunoglobulin isotypes was analyzed at the various amounts, 3-3,000 microg per mouse, of the antigen dosages. In our experiments, although alum did not adsorb KSTI significantly, it augmented the total and the antigen-specific IgE without affecting the optimal range of the antigen dosage. On the other hand, alum did not effectively enhance the production of the other immunoglobulin isotypes. The production of immunoglobulin isotypes other than IgE increased dose-dependently on the antigen. These results ensured our previous finding that another protein, ovalbumin, was used as the antigen. We also demonstrated that the adsorption of KSTI by DEAE-Sephadex in the immunizing vehicle resulted in the requirement of more KSTI for accomplishing the equal immunity in BALB/c mice compared to the control. Moreover, we demonstrated that, regardless of the inability to adsorb KSTI, alum exerted its adjuvant activity only when it was co-injected with the antigen. These results showed that some biochemical effect, other than adsorptive activity, to enhance the production of the antigen-specific IgE resides in alum.

Adjuvants, Immunologic↗
PubMed2002

Absorption and urinary excretion of procyanidin B2 [epicatechin-(4beta-8)-epicatechin] in rats.

We evaluated the bioavailability and plasma antioxidative activity after administration of procyanidin B2 [epicatechin-(4beta-8)-epicatechin] in rats. After procyanidin B2 administration, procyanidin B2 is absorbed and excreted in urine, and a portion of the PB2 is degraded to (-)-epicatechin and to the metabolized conjugated and/or methylated (-)-epicatechin internally in the rat. Moreover, PB2 reduces the accumulation of lipid peroxide in plasma oxidized by copper ions.

Administration, Oral↗