49 results on '"Tsutomu Nakayama"'
Search Results
2. Does Augmented Reality-based Portable Navigation Improve the Accuracy of Cup Placement in THA Compared With Accelerometer-based Portable Navigation? A Randomized Controlled Trial
- Author
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Kenji Kurosaka, Hiroyuki Ogawa, Naoyuki Hirasawa, Masayoshi Saito, Tsutomu Nakayama, and Sachiyuki Tsukada
- Subjects
Orthopedics and Sports Medicine ,Surgery ,General Medicine - Published
- 2023
3. Nano-visualization of the in vitro antiviral activity of black tea based on production area using a liposome-based virus membrane model
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Masumi Iijima, Atsushi Kawaguchi, Yukino Ogura, Ryotaro Yoshimoto, Moemi Kaneda, Kota Kera, Shun'ichi Kuroda, and Tsutomu Nakayama
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Tea ,Organic Chemistry ,General Medicine ,Virus Replication ,Applied Microbiology and Biotechnology ,Biochemistry ,Antiviral Agents ,Antioxidants ,Camellia sinensis ,Analytical Chemistry ,Cholesterol ,Liposomes ,Molecular Biology ,Biotechnology - Abstract
Black tea extracts (BTEs) from four different production areas showed a higher aggregation strength for phosphatidylcholine-based liposomes containing cholesterol used as a viral membrane model. Furthermore, the anti-influenza A virus (IAV) activity of each BTE in vitro demonstrated that although Sri Lanka, Kenya, and Assam had higher anti-IAV activities, Darjeeling had a lower anti-IAV activity, showing a correlation between each BTE and the liposome aggregation strength. Moreover, the antiviral activity strength of BTEs was consistent with the antioxidant activity strength of BTEs, suggesting that the component(s) in black tea that exhibits antioxidant activity would also be the component(s) that accounts for its antiviral activity. Thus, our results propose that BTEs exert their antiviral effects by binding not only hemagglutinin and neuraminidase but also viral membranes directly, especially “cholesterol-rich lipid rafts” and affect the membrane structure, causing the virus to aggregate, thereby inhibiting infection of the host cells.
- Published
- 2022
4. Enhanced sugar chain detection by oriented immobilization of Fc-fused lectins
- Author
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Tsutomu Nakayama, Masumi Iijima, Yuki Yamada, and Shun'ichi Kuroda
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0301 basic medicine ,Scaffold ,Recombinant Fusion Proteins ,Biosensing Techniques ,02 engineering and technology ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,03 medical and health sciences ,Protein Domains ,Chain (algebraic topology) ,Lectins ,Staphylococcus aureus protein A ,Humans ,Staphylococcal Protein A ,Sugar ,Molecular Biology ,Tandem ,Chemistry ,Organic Chemistry ,General Medicine ,021001 nanoscience & nanotechnology ,Immunoglobulin Fc Fragments ,Immobilized Proteins ,030104 developmental biology ,Immunoglobulin G ,Sugars ,0210 nano-technology ,Biosensor ,Biotechnology - Abstract
We report a novel scaffold for clustering and oriented immobilization of human IgG1 Fc-fused lectins on biosensors without chemical modifications. This approach uses a bio-nanocapsule (BNC) displaying a tandem form of IgG Fc-binding Z domains derived from Staphylococcus aureus protein A (ZZ-BNC). Incorporating ZZ-BNC effectively increased both the sensitivity and sugar chain-binding capacity compared with the condition without ZZ-BNC.
- Published
- 2020
5. Inhibitory effects of thiol compounds on theaflavin browning and structural analysis of the causative substances
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Asako Narai-Kanayama, Kazuhiro Chiku, Hiroshi Ono, Takamitsu Momoi, Miho Hiwatashi-Kanno, Akiko Kobayashi, Hiroko Matsuda, Mitsuru Yoshida, and Tsutomu Nakayama
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Biflavonoids ,Cysteine ,Sulfhydryl Compounds ,General Medicine ,Glutathione ,Oxidation-Reduction ,Antioxidants ,Catechin ,Acetylcysteine ,Food Science ,Analytical Chemistry - Abstract
Theaflavin, a polyphenol responsible for the bright orange color and various bioactivities of black tea exudates, is susceptible to autoxidation at neutral and mild alkaline pH, changing its color to brown. In the presence of cysteine (Cys), glutathione (GSH), or N-acetyl cysteine (NAC), the browning of theaflavin solution was inhibited concomitantly with time-dependent decreases in the concentrations of both theaflavin and thiol group. The rank order of the decrease was Cys ≅ GSH NAC, suggesting the relevance of the nucleophilic property of the thiol group to its reaction with theaflavin. LC-MS analysis of the reaction products indicated formation of novel derivatives that were mono- or di-molecular adducts of thiol compounds. We determined the chemical structures of theaflavin-Cys and theaflavin-GSH adducts by NMR and proposed the reaction mechanisms. It was found that the theaflavin-Cys adduct was not a simple adduct, to which a new cyclic structure was added.
- Published
- 2022
6. Theaflavin-3-gallate specifically interacts with phosphatidylcholine, forming a precipitate resistant against the detergent action of bile salt
- Author
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Natsumi Mori, Tsutomu Nakayama, Asako Narai-Kanayama, and Kosuke Saruwatari
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0301 basic medicine ,Detergents ,Salt (chemistry) ,Applied Microbiology and Biotechnology ,Biochemistry ,Micelle ,Catechin ,Intestinal absorption ,Analytical Chemistry ,Bile Acids and Salts ,03 medical and health sciences ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Gallic Acid ,Phosphatidylcholine ,Biflavonoids ,Molecular Biology ,Micelles ,chemistry.chemical_classification ,Theaflavin-3-gallate ,030109 nutrition & dietetics ,Vesicle ,Organic Chemistry ,04 agricultural and veterinary sciences ,General Medicine ,Gallate ,040401 food science ,Cholesterol ,Intestinal Absorption ,chemistry ,Polyphenol ,Phosphatidylcholines ,Biotechnology - Abstract
Black tea is a highly popular beverage, and its pigments, polymerized catechins such as theaflavins (TFs), are attracting attention due to their beneficial health effects. In this study, to test the inhibitory activities of TFs on the intestinal absorption of cholesterol, we investigated their effects on phosphatidylcholine (PC) vesicles in the absence or presence of a bile salt. (−)-Epicatechin gallate, (−)-epigallocatechin gallate, and TFs formed insoluble complexes with PC vesicles. Galloylated TFs such as TF2A, TF2B, and TF3 precipitated far more than other polyphenols. The subsequent addition of taurocholate redispersed the polyphenol-PC complexes, except that a large amount of TF2A remained insoluble. After incubation with taurocholate-PC micelles, TF2A elevated the turbidity of the micelle solution, providing red sediments. The TF2A-specific effect was dependent on the PC concentration. These results suggest that TF2A interacts with PC and aggregates in a specific manner different from catechins and other TFs.
- Published
- 2018
7. Two-dimensional membrane scaffold for the oriented immobilization of biosensing molecules
- Author
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Tsutomu Nakayama, Masumi Iijima, and Shun'ichi Kuroda
- Subjects
Scaffold ,Biomedical Engineering ,Biophysics ,Nanoparticle ,02 engineering and technology ,Biosensing Techniques ,Ligands ,01 natural sciences ,Micelle ,Nanocapsules ,Viral Envelope Proteins ,Electrochemistry ,Molecule ,Humans ,Lipid bilayer ,Membranes ,Tandem ,Chemistry ,010401 analytical chemistry ,General Medicine ,021001 nanoscience & nanotechnology ,Lipids ,0104 chemical sciences ,Immunoglobulin Fc Fragments ,Membrane ,Immunoglobulin G ,0210 nano-technology ,Biosensor ,Biotechnology - Abstract
The orientation and density of biosensing molecules on sensor chip should be precisely controlled to improve sensitivity and ligand-binding capacity. We previously developed a ~30-nm bio-nanocapsule (ZZ-BNC), consisting of the hepatitis B virus envelope L protein fused with the tandem form of protein A-derived IgG Fc-binding Z domain (ZZ-L protein). This is used as a robust nanoparticle scaffold to enhance the sensitivity and ligand-binding capacity of IgGs and Fc-fused sensing molecules (Fc-fused receptors). However, due to their rigid particle structure, the surface density of ZZ-L proteins could not be optimized for biosensor functions, and useless ZZ-L proteins become stuck between ZZ-BNC and the sensor chip. Here, we have developed a planar lipid membrane embedded with ZZ-L micelles (ZZ-L membrane), which could modify the surface of any biosensor chip with a controlled density of ZZ-L proteins. Compared with ZZ-BNC, the sensitivity and ligand-binding capacity of IgGs were enhanced about 10-fold with the ZZ-L membrane. Furthermore, the immobilized IgGs could capture their respective antigens almost stoichiometrically, indicating that ZZ-L membrane is the most ideal scaffold for Fc-fused sensing molecules in terms of both clustering and oriented immobilization.
- Published
- 2019
8. No Clinically Important Difference in Pain Scores After THA Between Periarticular Analgesic Injection and Placebo: A Randomized Trial
- Author
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Masahiro Nishino, Masaaki Matsubara, Tsutomu Nakayama, Kenji Kurosaka, Naoyuki Hirasawa, and Sachiyuki Tsukada
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Male ,Time Factors ,medicine.medical_treatment ,Arthroplasty, Replacement, Hip ,Minimal Clinically Important Difference ,law.invention ,Injections, Intra-Articular ,0302 clinical medicine ,Randomized controlled trial ,Japan ,law ,Medicine ,Orthopedics and Sports Medicine ,Ropivacaine ,030212 general & internal medicine ,Prospective Studies ,Prospective cohort study ,Pain Measurement ,030222 orthopedics ,Analgesics ,Pain, Postoperative ,Morphine ,Minimal clinically important difference ,General Medicine ,Middle Aged ,Drug Combinations ,Treatment Outcome ,Methylprednisolone ,Ketoprofen ,Anesthesia ,Female ,Hip Joint ,medicine.drug ,musculoskeletal diseases ,Epinephrine ,Analgesic ,Other Features ,Pain ,Placebo ,03 medical and health sciences ,Double-Blind Method ,Clinical Research ,Humans ,Aged ,business.industry ,Placebo Effect ,Arthroplasty ,Surgery ,business - Abstract
Background Periarticular analgesic injection (PAI) is being used more commonly for pain relief after orthopaedic surgeries. However, there is conflicting evidence regarding the effectiveness of PAI for post-THA pain relief. Questions/purposes In a double-blind, randomized, controlled trial among patients undergoing same-day bilateral THA, with each patient serving as his or her own control, we asked: (1) Did the pain score as measured on a 100-mm VAS differ between the hips that received PAI versus placebo? (2) Were there differences in complications between the treatment and control hips in these patients? Methods Over a 1-year period at one center, 45 patients underwent same-day bilateral THA; three were excluded for prespecified reasons, and two declined participation in this randomized, controlled trial, leaving 40 patients (80 THAs) in the study. Patients randomly received PAI in one hip and placebo in the contralateral hip; patients, surgeons, and nurses were blinded in terms of which hip received the PAI and which hip received a placebo saline injection. The PAI solution included ropivacaine, morphine hydrochloride hydrate, methylprednisolone, ketoprofen, and epinephrine. The primary outcome was the VAS for pain at rest 24 hours after THA, measured using a 100-mm horizontal VAS. The VAS score was compared between two groups and assessed to reach the reported threshold values for the minimum clinically important difference (MCID) of 20 mm for the postoperative VAS score. No patients were lost to followup, and there were no missing data for the primary outcome. Complications that occurred during the trial were recorded prospectively with emphasis on infection, wound complications, nerve palsy and allergic reactions to the injections. Results There were no clinically important differences between hips treated with the PAI and those treated with the placebo injection at any point. The hips that received PAI had less pain than those receiving placebo 24 hours after THA (16 ± 17 mm versus 22 ± 20 mm; mean difference, 6 mm; 95% confidence interval [CI], 2-9 mm; p = 0.006), but this effect size was below the MCID of 20 mm and thus is unlikely to be clinically important. The hips that received PAI also had better VAS scores in the recovery room (38 ± 29 mm versus 52 ± 33 mm; mean difference 14 mm; 95% CI, 5-23 mm; p = 0.004) and 3 hours after THA than placebo controls (28 ± 22 mm versus 37 ± 24 mm; mean difference 9 mm; 95% CI, 2-16 mm; p = 0.010). Neither of these differences exceeded the MCID and likewise were unlikely to be clinically important. No complications, including surgical site infections, were observed in either group. Conclusions Periarticular analgesic injection for pain control after THA did not result in a clinically important reduction in pain at any point examined. Given the expense associated with this PAI mixture and the lack of effectiveness outside this timeframe, we cannot recommend its use. Other mixtures or concentrations of drugs may be helpful in short-stay admissions for THA, but this will require further research. Level of evidence Level I, therapeutic study.
- Published
- 2018
9. The clinical and immunomodulatory effects of green soybean extracts
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Shinjiro Imai, Mamoru Isemura, Tsutomu Nakayama, Yuki Katayanagi, Ryuta Fukutomi, Kyoko Taguchi, Kensuke Yasui, and Hiroyuki Ikemoto
- Subjects
Adult ,Guinea Pigs ,Pilot Projects ,Mucous membrane of nose ,Pharmacology ,Biology ,Immunoglobulin E ,Analytical Chemistry ,Guinea pig ,Mice ,Animals ,Humans ,Immunologic Factors ,Secretion ,B-cell activating factor ,B-Lymphocytes ,Mice, Inbred BALB C ,Plant Extracts ,Rhinitis, Allergic, Seasonal ,Cedar pollinosis ,General Medicine ,Real-time polymerase chain reaction ,Seeds ,Glycine ,Immunology ,biology.protein ,Pollen ,Female ,Soybeans ,Food Science - Abstract
The present study was performed to investigate the immune-modulating activities of extracts from green soybean (Glycine max) in a 2,4-toluene diisocyanate (TDI)-inducing guinea pig rhinitis model and a human trial study for allergic rhinitis. Hot water extracts of green soybean were chosen for animal experimentation on the basis of their ability to regulate the production of B cell-activating factor of the TNF family and a proliferation-inducing ligand in mouse spleen cells. Green soybean extracts significantly decreased the levels of ovalubumin (OVA)-specific IgE in mice and significantly suppressed the TDI-induced nasal mucosa secretion. An open-label human pilot study was performed on 16 subjects, using Japanese cedar pollinosis. The symptom scores for Japanese cedar pollinosis were better in the long-term green soybean extracts intake group than in the withdrawal short-term intake group. Green soybean extracts had great potential as an orally active immune modulator for the treatment of various allergic diseases.
- Published
- 2013
10. Effects of a catechin-free fraction derived from green tea on gene expression of enzymes related to lipid metabolism in the mouse liver
- Author
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Noriko Paeng, Yoko Ishigami, Ryuuta Fukutomi, Tsutomu Nakayama, Mamoru Isemura, Kyoko Taguchi, Takuji Suzuki, Noriyuki Miyoshi, Kensuke Yasui, and Shinjiro Imai
- Subjects
Blood Glucose ,Male ,Arteriosclerosis ,Coenzyme A ,Down-Regulation ,Real-Time Polymerase Chain Reaction ,complex mixtures ,Catechin ,General Biochemistry, Genetics and Molecular Biology ,Mice ,chemistry.chemical_compound ,Gene expression ,Animals ,Obesity ,Triglycerides ,chemistry.chemical_classification ,Mice, Inbred BALB C ,Tea ,biology ,Plant Extracts ,food and beverages ,Lipid metabolism ,Promoter ,General Medicine ,Lipid Metabolism ,Molecular biology ,Plant Leaves ,Fatty acid synthase ,Cholesterol ,Enzyme ,Liver ,chemistry ,Biochemistry ,Glucose-6-Phosphatase ,biology.protein ,sense organs ,Sterol Regulatory Element Binding Protein 1 ,Phosphoenolpyruvate carboxykinase ,Phosphoenolpyruvate Carboxykinase (ATP) ,Sterol Regulatory Element Binding Protein 2 - Abstract
Many biological activities of green tea have been attributed to a major constituent, (minus;)-epigallocatechin gallate (EGCG). We previously reported that EGCG and an EGCG-free fraction derived from green tea modulated the gene expression of gluconeogenic enzymes, glucose-6-phosphatase and phosphoenolpyruvate carboxykinase, in the mouse liver. EGCG is also known to affect the gene expression of enzymes related to lipid metabolism. However, it remains to be examined whether or not a constituent other than EGCG contributes to the change in gene expression of these enzymes. In this study, we prepared an EGCG-free water-soluble fraction (GT-W), and examined its effects on the hepatic gene expression of lipogenic enzymes in mice. The results of quantitative real-time PCR assays indicated that the dietary administration of GT-W for 4 weeks reduced the hepatic gene expression of lipogenic enzymes: fatty acid synthase, hydroxymethylglutaryl coenzyme A reductase, and acetyl-coenzyme A carboxylase alpha. Also, the gene expression of sterol regulatory element-binding transcription factor (Srebf)1 and/or Srebf2 was reduced, suggesting that the reduction of Srebfs contributed to the down-regulation of the lipogenic enzymes, since these transcription factors bind the promoter region to enhance their expression. The plasma levels of triglycerides and cholesterol were reduced with statistical significance in the group given a diet containing GT-W. These results suggest that in addition to EGCG, green tea contains some component(s) which may help to prevent arteriosclerosis and obesity.
- Published
- 2012
11. Evaluation of Superoxide Anion Radicals Generated from an Aqueous Extract of Particulate Phase Cigarette Smoke by Electron Spin Resonance Using 5,5-Dimethyl-1-pyrroline-N-oxide
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Yuichiro Takanami and Tsutomu Nakayama
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Catechols ,Photochemistry ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,law.invention ,Cyclic N-Oxides ,Superoxide dismutase ,chemistry.chemical_compound ,Superoxides ,law ,Smoke ,Tobacco ,Pyrroles ,Electron paramagnetic resonance ,Molecular Biology ,chemistry.chemical_classification ,Reactive oxygen species ,Oxidase test ,biology ,Hydroxyl Radical ,Superoxide ,Organic Chemistry ,Electron Spin Resonance Spectroscopy ,Water ,Free Radical Scavengers ,Hydrogen Peroxide ,General Medicine ,Resonance (chemistry) ,Hydroquinones ,Oxygen ,chemistry ,Catalase ,biology.protein ,Particulate Matter ,Hydroxyl radical ,Biotechnology - Abstract
The reactive oxygen species generated by an aqueous extract of the particulate phase of cigarette smoke were evaluated by an electron spin resonance (ESR) analysis, using spin-trapping agents, and by comparing with model reaction systems. The ESR signals of DMPO-OH were detected from the extract by using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). These signals were eliminated by adding superoxide dismutase, but hardly by catalase. These responses of the ESR signals to the scavengers were similar to those of a hypoxanthine-xanthine oxidase system. The results indicate that the signals of DMPO-OH from the extract were derived from a reaction product of DMPO with superoxide anion radicals and clarify the mechanism by which the extract generated superoxide anion radicals.
- Published
- 2011
12. Proteomic Identification of Serum Proteins Associated with Stress-Induced Gastric Ulcers in Fasted Rats
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Tsutomu Nakayama, Hirotaka Naitou, Kato Ayako, Hiroyuki Sakakibara, Masanobu Akimoto, Takeshi Ishii, Kayoko Shimoi, Makoto Namioka, and Norio Ohashi
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Male ,medicine.medical_specialty ,Apolipoprotein B ,Enzyme-Linked Immunosorbent Assay ,Apolipoprotein A-IV ,Proteomics ,Applied Microbiology and Biotechnology ,Biochemistry ,Analytical Chemistry ,Rats, Sprague-Dawley ,APOA4 ,Internal medicine ,Immersion ,Animals ,Medicine ,Stomach Ulcer ,Molecular Biology ,Apolipoproteins A ,chemistry.chemical_classification ,biology ,business.industry ,Organic Chemistry ,Proteins ,Blood Proteins ,General Medicine ,Blood proteins ,digestive system diseases ,Rats ,Blot ,Enzyme ,Endocrinology ,chemistry ,Duodenal Ulcer ,biology.protein ,Creatine kinase ,business ,Stress, Psychological ,Biotechnology - Abstract
Several physical and psychological stresses frequently become triggers for gastrointestinal disorders such as ulcer. In this study, we tried to identify serum proteins as potential biomarkers for the evaluation of stress-induced gastric ulcer. By proteomic analysis using rats with gastric ulcer induced by water immersion and restraint (WIR) stress as an animal model, we found quantitative changes in several serum proteins, including creatine kinase muscle M chain (CK-M) and apolipoprotein A-IV (ApoA4) in the stressed rats. On western blotting and enzyme-linked immunosorbent assay (ELISA), we confirmed that serum CK-M was remarkably increased by WIR stress. However, ApoA4 appeared to be decreased by fasting, but not WIR stress, which is usually applied prior to WIR stress. The findings suggest that these two serum proteins might be useful as biomarkers, CK-M for stress-induced gastric ulcer and ApoA4 for starvation.
- Published
- 2010
13. A new method for the detection and characterization of α-lipoic acid mixed disulphides
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Tsutomu Nakayama, Miyuki Wakabayashi, Takeshi Ishii, and Taiki Mori
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Stereochemistry ,Direct evidence ,Tandem mass spectrometry ,Mass spectrometry ,Biochemistry ,Iodoacetamide ,chemistry.chemical_compound ,Tandem Mass Spectrometry ,Cysteine ,Disulfides ,Sulfhydryl Compounds ,Incubation ,Chromatography, High Pressure Liquid ,Chromatography ,Glutathione Disulfide ,Thioctic Acid ,Chemistry ,General Medicine ,Glutathione ,Peptide Fragments ,Lipoic acid ,Matrix-assisted laser desorption/ionization ,Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ,Calcium-Calmodulin-Dependent Protein Kinase Type 2 ,Intracellular - Abstract
Alpha-lipoic acid (LA) acts as a direct regulator of intracellular redox status through the formation of mixed disulphides. However, as this is reversible, the evidence for the mixed disulphides has not been obtained. This study established a method for the detection and characterization of mixed disulphides by mass spectrometry (MS) and was the first to provide direct evidence for their formation. When cysteine methyl ester was incubated with LA in the presence of iodeacetamide (IAA), a mixed disulphide with mono carbamidomethylation was observed. MS/MS analysis indicated that the LA forms a mixed disulphide with the cysteinyl sulphydryls, while the other sulphydryl group is the carbamidomethylated. The same results were obtained from the incubation of sulfphydryl peptides such as glutathione with LA in the presence of IAA. These results may provide further biological evidence that LA is a potential modifier of intracellular sulphydryls through mixed disulfide formation.
- Published
- 2010
14. Analysis of Hydrogen Peroxide in an Aqueous Extract of Cigarette Smoke and Effect of pH on the Yield
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Tsutomu Nakayama, Takako Moriyama, Yasutaka Kosaka, and Yuichiro Takanami
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Smoke ,Chromatography ,Smoking ,Organic Chemistry ,Extraction (chemistry) ,Water ,Hydrogen Peroxide ,General Medicine ,Chemical Fractionation ,Hydrogen-Ion Concentration ,Particulates ,Electrochemistry ,Applied Microbiology and Biotechnology ,Biochemistry ,High-performance liquid chromatography ,Injections ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Hydrogen peroxide ,Molecular Biology ,Phosphoric acid ,Biotechnology - Abstract
An analysis of hydrogen peroxide in an aqueous extract of cigarette smoke, which contains many redox-active compounds, requires a method with high selectivity. An aqueous extract of the particulate phase of cigarette smoke was analyzed by HPLC with an electrochemical detector (ECD). Samples were prepared by collecting the particulate phase of the cigarette smoke on a glass fiber filter and extracting it with a phosphate buffer. The obtained solution was purified by using a Waters Oasis MCX cation-exchange cartridge, and then analyzed by an HPLC-ECD system with a Shodex KS-801 mixed-mode resin column. Pre-injecting hydrogen peroxide at a high concentration into the HPLC instrument stabilized the analytical results. The recovery of hydrogen peroxide by using an extract of the particulate phase of the cigarette smoke was more than 80%. An increase in the amount of hydrogen peroxide was observed during extraction with the phosphate buffer at higher pH values. In contrast, extraction with phosphoric acid did not increase the amount of hydrogen peroxide during extraction.
- Published
- 2009
15. Partition Coefficients of Polyphenols for Phosphatidylcholine Investigated by HPLC with an Immobilized Artificial Membrane Column
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Takeshi Ishii, Yuko Takeshita, Tsutomu Nakayama, and Yoshinori Uekusa
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Synthetic membrane ,Applied Microbiology and Biotechnology ,Biochemistry ,High-performance liquid chromatography ,Analytical Chemistry ,Anthocyanins ,chemistry.chemical_compound ,Phenols ,Phosphatidylcholine ,Molecular Biology ,Chromatography, High Pressure Liquid ,Flavonoids ,Liposome ,Chromatography ,Chemistry ,Cell Membrane ,Organic Chemistry ,Polyphenols ,food and beverages ,Membranes, Artificial ,Biological activity ,General Medicine ,Partition coefficient ,Membrane ,Polyphenol ,Phosphatidylcholines ,Biotechnology - Abstract
The biological activity of polyphenols in vitro reflects their affinity for cell membranes and the amount of cellular incorporation. The interaction of polyphenols with phosphatidylcholine was investigated by HPLC with an immobilized artificial membrane (IAM) column. The IAM partition coefficients (K(IAM)) of the polyphenols, calculated by retention times, correlated well with the amounts of polyphenols incorporation into the liposomes.
- Published
- 2008
16. Effect of flavour components in lemon essential oil on physical or psychological stress
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Kohei Furutachi, Tsutomu Nakayama, Takehiko Terashima, Syuichi Fukumoto, Hidehiko Yokogoshi, and Aya Morishita
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Limonene ,Metabolite ,General Medicine ,Citral ,law.invention ,Psychiatry and Mental health ,Clinical Psychology ,chemistry.chemical_compound ,Monoamine neurotransmitter ,chemistry ,law ,Ingestion ,Food science ,Applied Psychology ,Flavor ,Essential oil ,Aromatherapy - Abstract
Citrus essential oils, including lemon essential oil, have long been used widely in aromatherapy and alternative medicine. This study was designed to assess the effects of flavour components in lemon essential oil on physical and psychological stress. In this evaluation, acute cold stress and communication box techniques were used to apply stress after intraperitoneal administration of essential oil components such as limonene, γ-terpinene and citral. Serum corticosterone and monoamines in brain tissues were then determined. In the present study, it found the presence of perillic acid, a limonene metabolite, at concentrations of 1.5–2.5 μg/mL in serum and 0.4–0.6 μg/g in brain tissue collected 3 h after administration. The research also showed that the lemon components R-limonene, citral and γ-terpinene inhibited elevation of serum corticosterone levels and cerebral monoamine levels. S-limonene, a stereoisomer of R-limonene, seemed to have stronger effect than other monoterpenes and inhibited brain monoamines elevation on psychological stress. These findings suggest that limonenes, and particularly S-limonene, have a potent stress-alleviating effect, and the possibility that different stereoisomers of limonene have different levels of activity in their effect on stress responses. These results suggest a possibility that ingestion of lemon essential oil containing components such as limonene and citral alleviates both physical and psychological stress. Copyright © 2007 John Wiley & Sons, Ltd.
- Published
- 2008
17. Antioxidant activity and constituents of propolis collected in various areas of China
- Author
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Yumiko Usui, Jun Nakamura, Mok-Ryeon Ahn, Shigenori Kumazawa, Fang Zhu, Mitsuo Matsuka, and Tsutomu Nakayama
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Antioxidant ,ABTS ,DPPH ,medicine.medical_treatment ,General Medicine ,Propolis ,Analytical Chemistry ,Ferulic acid ,chemistry.chemical_compound ,chemistry ,Polyphenol ,parasitic diseases ,medicine ,Caffeic acid ,Food science ,Caffeic acid phenethyl ester ,Food Science - Abstract
Propolis is a resinous substance collected by honeybees from various plant sources. The composition of propolis depends on time, vegetation, and the area of collection. This study examined the antioxidant activity of propolis from various areas of China: Heilongjiang, Neimongol, Hebei, Shandong, Shanxi, Gansu, Henan, Hubei, Sichuan, Hunan, Yunnan and Hainan. Ethanol extracts of propolis (EEP) were prepared and evaluated for their antioxidant activities by β-carotene bleaching, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging, and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation decolorization assays. Furthermore, the major constituents in EEP were identified by high-performance liquid chromatography (HPLC) analysis with a photodiode array (PDA) and mass spectrometric (MS) detection, and each component was quantitatively analyzed. All propolis samples except that from Yunnan had relatively strong antioxidant activity accompanied by high total polyphenol contents. Propolis with strong antioxidant activity contained large amounts of antioxidative compounds, such as caffeic acid, ferulic acid and caffeic acid phenethyl ester. On the other hand, propolis from Yunnan and Hainan had compounds not present in propolis from other areas.
- Published
- 2007
18. Antioxidant activity of propolis of various geographic origins
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Shigenori Kumazawa, Tsutomu Nakayama, and Tomoko Hamasaka
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chemistry.chemical_classification ,Hplc analysis ,Antioxidant ,Traditional medicine ,DPPH ,medicine.medical_treatment ,Flavonoid ,General Medicine ,Propolis ,Biology ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Polyphenol ,parasitic diseases ,medicine ,Organic chemistry ,Phenols ,Kaempferol ,Food Science - Abstract
Propolis is a resinous substance collected by honeybees from various plant sources. The antioxidant activities of propolis of various geographic origins, i.e., Argentina, Australia, Brazil, Bulgaria, Chile, China (Hebei, Hubei, and Zhejiang), Hungary, New Zealand, South Africa, Thailand, Ukraine, Uruguay, United States, and Uzbekistan were compared. Ethanol extracts of propolis (EEP) were prepared and evaluated for antioxidant activities of EEP samples by the β-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay systems. Major constituents were identified in EEP by HPLC analysis with photo-diode array (PDA) and mass spectrometric (MS) detection, and quantitatively analyzed. EEP from Argentina, Australia, China, Hungary and New Zealand had relatively strong antioxidant activities, and were also correlated with the total polyphenol and flavonoid contents. Propolis with strong antioxidant activity contained antioxidative compounds such as kaempferol and phenethyl caffeate.
- Published
- 2004
19. Effect of quercetin conjugates on vascular permeability and expression of adhesion molecules
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Tsutomu Nakayama, Shigenori Kumazawa, Junji Terao, Kazuhiko Kaji, Katsuko Kajiya, Kayoko Shimoi, and Mika Mochizuki
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Cell Membrane Permeability ,Vascular smooth muscle ,Endothelium ,Lipid Bilayers ,Clinical Biochemistry ,Intercellular Adhesion Molecule-1 ,Vascular permeability ,Biochemistry ,Capillary Permeability ,chemistry.chemical_compound ,medicine ,heterocyclic compounds ,Glycosides ,Aorta ,Cells, Cultured ,ICAM-1 ,Liposome ,Cell adhesion molecule ,General Medicine ,medicine.anatomical_structure ,chemistry ,Molecular Medicine ,Quercetin ,Endothelium, Vascular ,Cell Adhesion Molecules - Abstract
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.
- Published
- 2004
20. Characterization of γ-terpinene synthase fromCitrus unshiu(Satsuma mandarin)
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Mitsuo Omura, Yukiko Suzuki, Hiroshi Sakai, Tsutomu Nakayama, Takehiko Shimada, and Shigenori Kumazawa
- Subjects
Citrus ,Monoterpene ,Clinical Biochemistry ,medicine.disease_cause ,Biochemistry ,Gas Chromatography-Mass Spectrometry ,chemistry.chemical_compound ,Escherichia coli ,medicine ,Cloning, Molecular ,Terpinene ,Gene ,Plant Proteins ,Cloning ,chemistry.chemical_classification ,Alkyl and Aryl Transferases ,ATP synthase ,biology ,Terpenes ,food and beverages ,General Medicine ,biology.organism_classification ,Recombinant Proteins ,Citrus unshiu ,Enzyme ,chemistry ,biology.protein ,Molecular Medicine - Abstract
Gamma-terpinene is a monoterpene and a major component of essential oils made from citrus fruits and shows strong antioxidant activity in various assay systems. Plant gamma-terpinene synthase is a member of the monoterpene cyclase family, which produces a specific monoterpene through cyclization of geranyl diphosphate (GPP), but the monoterpene cyclases have not been fully characterized. It is necessary to prepare large amounts of gamma-terpinene synthase from Citrus unshiu (Satsuma mandarin) for the characterization, on this purpose we expressed the protein in Escherichia coli (E. coli) cells. As most monoterpene synthases have plastid-targeting signals, a gene lacking these signals was prepared and functionally expressed in E. coli cells harboring extra copies of the argU gene. The purified enzyme was incubated with GPP and the main product was confirmed to be gamma-terpinene by GC/MS.
- Published
- 2004
21. Isolation of Sesaminols as Antioxidative Components from Roasted Sesame Seed Oil
- Author
-
Tsutomu Nakayama, Shigenori Kumazawa, Yasuko Fukuda, Yumiko Usui, and Miho Koike
- Subjects
Antioxidant ,General Chemical Engineering ,medicine.medical_treatment ,food and beverages ,General Medicine ,General Chemistry ,Sesame seed ,chemistry.chemical_compound ,chemistry ,Botany ,medicine ,Browning ,Food science ,Sesamol ,Roasting - Abstract
Two antioxidative compounds were isolated from the oil of sesame seeds roasted at 230°C for 15 min and identified as sesaminols (isomers) by MS and NMR analysis. Although sesaminols are present in refined unroasted sesame seed oil, we have demonstrated their presence also in the oil from the roasted sesame seed without refining for the first time. Furthermore, the amounts of sesaminols in sesame seeds were increased by roasting. Sesamol and melanoidin-like browning compounds have been believed to contribute to the antioxidant activity of roasted sesame seed oil, but the present study revealed that sesaminols also play an important role in the antioxidant activity of roasted sesame seed oil.
- Published
- 2003
22. Affinity of isoflavonoids for lipid bilayers evaluated with liposomal systems
- Author
-
Shigenori Kumazawa, Ryuichi Kato, Hiromi Tokumoto, Katsuko Kajiya, and Tsutomu Nakayama
- Subjects
endocrine system ,Time Factors ,Cell Survival ,Lipid Bilayers ,Clinical Biochemistry ,Genistein ,In Vitro Techniques ,Biochemistry ,chemistry.chemical_compound ,Isoflavonoid ,Cricetinae ,Animals ,Cytotoxicity ,Lipid bilayer ,Chromatography, High Pressure Liquid ,Fluorescent Dyes ,Liposome ,Chromatography ,General Medicine ,Fibroblasts ,Isoflavones ,In vitro ,Partition coefficient ,chemistry ,Liposomes ,Lipophilicity ,Molecular Medicine - Abstract
Three parameters, i.e., the proportion of the amount incorporated into the liposomes, the partition coefficient in a system of n-octanol/phosphate buffered saline, and the retention times by HPLC, were measured to determine the lipophilicity of isoflavonoids. The presence of a hydroxyl group at 5-position of the A-ring and a methoxyl group at 4'-position of the B-ring in the isoflavonoid structure increased the three parameters. The localization of isoflavonoids in lipid bilayers was investigated by a liposome system with fluorescent probes. The location of the isoflavonoid depended on its structure. The cytotoxicity of isoflavonoids was investigated by a colony-formation assay with Chinese hamster lung fibroblast V79 cells. The structure-activity relationship of the cytotoxic activity partly reflected those of the three parameters. This suggests that the biological activities of isoflavonoids in vitro could be attributable to their affinity for lipid components in the cases where the estrogen receptors have no role.
- Published
- 2003
23. The human bitter taste receptor hTAS2R39 is the primary receptor for the bitterness of theaflavins
- Author
-
Noriko Matsuda, Tsutomu Nakayama, Tatsuo Watanabe, Toyomi Yamazaki, Riko Ikeda, Toshiyuki Nakamura, Takeshi Ishii, and Miki Sagisaka
- Subjects
chemistry.chemical_element ,Receptors, Cell Surface ,Pharmacology ,Calcium ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,Biflavonoids ,Humans ,Food science ,Theaflavin ,Receptor ,Molecular Biology ,Organic Chemistry ,HEK 293 cells ,Taste Perception ,General Medicine ,Bitter taste ,HEK293 Cells ,chemistry ,Biotechnology - Abstract
We purified several hundred mgs of four major theaflavins (theaflavin, theaflavin-3-O-gallate, theaflavin-3′-O-gallate, and theaflavin-3,3′-O-digallate). Among the 25 hTAS2Rs expressed in HEK293T cells, hTAS2R39 and hTAS2R14 were activated by theaflavins. Both hTAS2R39 and hTAS2R14 responded to theaflavin-3′-O-gallate. In addition, hTAS2R39 was activated by theaflavin and theaflavin-3,3′-O-gallate, but not by theaflavin-3-O-gallate. In contrast, hTAS2R14 responded to theaflavin-3-O-gallate.
- Published
- 2014
24. Steric Effects on Interaction of Tea Catechins with Lipid Bilayers
- Author
-
Shigenori Kumazawa, Tsutomu Nakayama, and Katsuko Kajiya
- Subjects
Models, Molecular ,Steric effects ,Liposome ,Molecular Structure ,Tea ,Stereochemistry ,Chemistry ,Lipid Bilayers ,Organic Chemistry ,Membrane structure ,Stereoisomerism ,General Medicine ,Fluoresceins ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,Partition coefficient ,Spectrometry, Fluorescence ,Membrane ,Moiety ,Lipid bilayer ,Molecular Biology ,Biotechnology - Abstract
Interaction of tea catechins with lipid bilayers has been investigated with liposome systems. Tea catechins are classified into cis-type and trans-type from the configuration of the two hydrogens at the 2 and 3 positions on the C-ring. The amount of trans-type catechins incorporated into liposomes was less than that of the respective cis-type catechins. Furthermore, the order of the partition coefficients of catechins in an n-octanol/PBS system is the same as that of the amount incorporated into liposomes. These results indicate that in addition to the number of hydroxyl groups on the B-ring and the presence of the galloyl moiety, the stereochemical structure of the C-ring also governs the hydrophobicity and the affinity for lipid bilayers. Trans-type catechins with the galloyl moiety were located on the surface of the lipid bilayer, as well as cis-type catechins with the galloyl moiety, and perturbed the membrane structure. These different stereochemical structures should influence the affinity for lipid bilayers, the alteration of membrane structures, and the difference in the order of the biological activities.
- Published
- 2001
25. Affinity of polyphenols for lipid bilayers
- Author
-
Toshihiko Hashimoto, Katsuko Kajiya, Tsutomu Nakayama, and Shigenori Kumazawa
- Subjects
Models, Molecular ,Polymers ,Lipid Bilayers ,Clinical Biochemistry ,Molecular Conformation ,Apoptosis ,Tumor cells ,Epigallocatechin gallate ,complex mixtures ,Biochemistry ,Catechin ,Structure-Activity Relationship ,chemistry.chemical_compound ,Phenols ,Tumor Cells, Cultured ,Animals ,Anticarcinogenic Agents ,Structure–activity relationship ,heterocyclic compounds ,Lipid bilayer ,Flavonoids ,Liposome ,Chromatography ,Bacteria ,Molecular Structure ,Tea ,Membrane structure ,food and beverages ,General Medicine ,Anti-Bacterial Agents ,Epicatechin gallate ,chemistry ,Polyphenol ,Molecular Medicine ,lipids (amino acids, peptides, and proteins) ,sense organs - Abstract
Interaction of tea catechins with lipid bilayers has been investigated with liposome systems. Epicatechin gallate had the highest affinity for lipid bilayers, followed by epigallocatechin gallate, epicatechin, and epigallocatechin. Epicatechin gallate and epigallocatechin gallate in the surface of lipid bilayer perturbed the membrane structure.
- Published
- 2000
26. Interaction of Tea Catechins with Lipid Bilayers Investigated with Liposome Systems
- Author
-
Fumio Nanjo, Yukihiko Hara, Toshihiko Hashimoto, Tsutomu Nakayama, and Shigenori Kumazawa
- Subjects
Polymers ,Lipid Bilayers ,Epigallocatechin gallate ,complex mixtures ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,Phenols ,heterocyclic compounds ,Centrifugation ,Gallic acid ,Lipid bilayer ,Molecular Biology ,Flavonoids ,Liposome ,Chromatography ,Dose-Response Relationship, Drug ,Tea ,Organic Chemistry ,food and beverages ,General Medicine ,Epicatechin gallate ,Models, Chemical ,chemistry ,Polyphenol ,Liposomes ,lipids (amino acids, peptides, and proteins) ,sense organs ,Biotechnology - Abstract
Interaction of tea catechins with lipid bilayers was investigated with liposome systems, which enabled us to separate liposomes from the external medium by centrifugation. We found that epicatechin gallate had the highest affinity for lipid bilayers, followed by epigallocatechin gallate, epicatechin, and epigallocatechin. Epicatechin gallate and epigallocatechin gallate in the surface of lipid bilayer perturbed the membrane structure.
- Published
- 1999
27. Superoxide Dismutase Inhibition of Oxidation of Ubiquinol and Concomitant Formation of Hydrogen Peroxide
- Author
-
Tsutomu Nakayama, Miku Hashimoto, and Kei Hashimoto
- Subjects
chemistry.chemical_classification ,Reactive oxygen species ,Ubiquinol ,Antioxidant ,biology ,Superoxide ,medicine.medical_treatment ,Organic Chemistry ,General Medicine ,Applied Microbiology and Biotechnology ,Biochemistry ,Medicinal chemistry ,Cofactor ,Analytical Chemistry ,Superoxide dismutase ,chemistry.chemical_compound ,Enzyme ,chemistry ,biology.protein ,medicine ,Hydrogen peroxide ,Molecular Biology ,Biotechnology - Abstract
We measured ubiquinone (CoQ0) and hydrogen peroxide (H2O2) formed in the process of oxidation of ubiquinol (CoQ0H2). We found that copper-zinc superoxide dismutase and manganese superoxide dismutase inhibited both the CoQ0 formation and the H2O2 formation only in the presence of chelators such as DTPA (diethylenetriaminepentaacetic acid). The amount of H2O2 was almost equal to that of CoQ0, indicating that the H2O2 formation was coupled with the CoQ0 formation. The lack of inhibitory effects of the corresponding heat-inactivated superoxide dismutase (SOD) confirmed that the inhibition by the original SOD was due to its enzymatic activity. We propose that CoQ0H2 oxidation occurs as a chain reaction with superoxide as the chain carrier and that SOD inhibits this reaction by lowering the superoxide concentration.
- Published
- 1997
28. Identification of Licocoumarone as an Apoptosis-Inducing Component in Licorice
- Author
-
Sumio Hayakawa, Chihiro Mori, Makoto Watanabe, Tsutomu Nakayama, Mamoru Isemura, Shigenori Kumazawa, and Toshioki Kawakami
- Subjects
Pharmacology ,Programmed cell death ,U937 cell ,Traditional medicine ,Plant Extracts ,Cell growth ,Monoblast ,Pharmaceutical Science ,Apoptosis ,Biological activity ,U937 Cells ,General Medicine ,Biology ,Pharmacognosy ,Plant Roots ,Growth Inhibitors ,In vitro ,Biochemistry ,Glycyrrhiza ,Humans ,Benzofurans - Abstract
The 70% methanol soluble fraction from a licorice acetone extract was found to inhibit cell proliferation in human monoblastic leukemia U937 cells by inducing apoptosis. Separation by the methods including preparative HPLC provided us with an active compound, which was identified as licocoumarone. Several lines of evidence indicated that licocoumarone induced apoptosis in U937 cells. Thus, licocoumarone is suggested to be potentially useful as a natural anti-cancer agent.
- Published
- 2002
29. Human serum albumin as an antioxidant in the oxidation of (-)-epigallocatechin gallate: participation of reversible covalent binding for interaction and stabilization
- Author
-
Mitsugu Akagawa, Kanako Minoda, Tsutomu Nakayama, Toshinao Goda, Yukiko Suzuki, Kazuki Mochizuki, Koji Kusaka, Tatsuya Ichikawa, Sohei Ito, and Takeshi Ishii
- Subjects
Antioxidant ,medicine.medical_treatment ,Serum albumin ,Plasma protein binding ,Epigallocatechin gallate ,Pyrogallol ,complex mixtures ,Applied Microbiology and Biotechnology ,Biochemistry ,Antioxidants ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,medicine ,Humans ,heterocyclic compounds ,Molecular Biology ,Serum Albumin ,Amination ,biology ,Chemistry ,Organic Chemistry ,food and beverages ,Water ,General Medicine ,Gallate ,Human serum albumin ,Aerobiosis ,body regions ,Covalent bond ,biology.protein ,sense organs ,Oxidation-Reduction ,Biotechnology ,medicine.drug ,Protein Binding - Abstract
Human serum albumin (HSA) contributes to the stabilization of (-)-epigallocatechin gallate (EGCg) in serum. We characterize in the present study the mechanisms for preventing EGCg oxidation by HSA. EGCg was stable in human serum or buffers with HSA, but (-)-epigallocatechin (EGC) was unstable. We show by comparing EGCg and EGC in a neutral buffer that EGCg had a higher binding affinity than EGC. This indicates that the galloyl moiety participated in the interaction of EGCg with HSA and that this interaction was of critical importance in preventing EGCg oxidation. The binding affinity of EGCg for HSA and protein carbonyl formation in HSA were enhanced in an alkaline buffer. These results suggest the reversible covalent modification of EGCg via Schiff-base formation, and that the immobilization of EGCg to HSA, through the formation of a stable complex, prevented the polymerization and decomposition of EGCg in human serum.
- Published
- 2011
30. Covalent binding of tea catechins to protein thiols: the relationship between stability and electrophilic reactivity
- Author
-
Mitsugu Akagawa, Taiki Mori, Tsutomu Nakayama, Yoshimasa Nakamura, and Takeshi Ishii
- Subjects
Peptide ,Electrons ,complex mixtures ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,Drug Stability ,Organic chemistry ,Reactivity (chemistry) ,Sulfhydryl Compounds ,Molecular Biology ,chemistry.chemical_classification ,Autoxidation ,Tea ,Organic Chemistry ,food and beverages ,Proteins ,Biological activity ,General Medicine ,chemistry ,Polyphenol ,Covalent bond ,Thiol ,Peptides ,Reactive Oxygen Species ,Oxidation-Reduction ,Biotechnology - Abstract
In this study, we investigated the relationship between the stability of catechins and their electrophilic reactivity with proteins. The stability of catechins was evaluated by HPLC analysis. Catechol-type catechins were stable in a neutral buffer, but pyrogallol-type catechins, such as (-)-epigallocatechin gallate (EGCg), were unstable. The electrophilic reactivity of catechins with thiol groups in a model peptide and a protein was confirmed by both mass spectrometry and electrophoresis/blotting with redox-cycling staining. In a comparison of several catechins, pyrogallol-type catechins had higher reactivity with protein thiols than catechol-type catechins. The instability and reactivity of EGCg were enhanced in an alkaline pH buffer. The reactivity of EGCg was reduced by antioxidants due to their ability to prevent EGCg autoxidation. These results indicate that the instability against oxidation of catechins is profoundly related to their electrophilic reactivity. Consequently, the difference in these properties of tea catechins can contribute to the magnitude of their biological activities.
- Published
- 2010
31. Pro-oxidant action of pyrroloquinoline quinone: characterization of protein oxidative modifications
- Author
-
Yuji Naito, Toshikazu Yoshikawa, Tsutomu Nakayama, Takeshi Ishii, Osamu Handa, Taiki Mori, Mitsugu Akagawa, Shigenori Kumazawa, and Tomohisa Takagi
- Subjects
PQQ Cofactor ,Peptide ,Oxidative phosphorylation ,Applied Microbiology and Biotechnology ,Biochemistry ,Redox ,Antioxidants ,Analytical Chemistry ,Protein Carbonylation ,chemistry.chemical_compound ,Pyrroloquinoline quinone ,Molecular Biology ,chemistry.chemical_classification ,Intracellular protein ,Chemistry ,Organic Chemistry ,Proteins ,General Medicine ,Pro-oxidant ,Quinone ,Oxidative Stress ,Posttranslational modification ,Reactive Oxygen Species ,Oxidation-Reduction ,Biotechnology - Abstract
Pyrroloquinoline quinone (PQQ), a putative essential nutrient, is a redox modulator in cell and animal models. Here we characterized PQQ-induced protein oxidative modifications in a model peptide and protein, and we propose that the mechanism of protein modification by PQQ is redox cycling-mediated oxidation. PQQ may contribute to the regulation of intracellular protein functions through its prooxidant action.
- Published
- 2010
32. Interaction of tea catechins with lipid bilayers investigated by a quartz-crystal microbalance analysis
- Author
-
Tsutomu Nakayama, Mikihiko Nakamura, Hiromi Nakazawa, Atsushi Kira, Yumi Mizutani, and Miya Kamihira
- Subjects
Lipid Bilayers ,Epigallocatechin gallate ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,Lipid bilayer ,Molecular Biology ,Chromatography ,Tea ,Bilayer ,Organic Chemistry ,Biological activity ,General Medicine ,Quartz crystal microbalance ,Quartz ,Tea catechin ,Kinetics ,Epicatechin gallate ,chemistry ,Adsorption ,Dimyristoylphosphatidylcholine ,Biotechnology ,Nuclear chemistry - Abstract
The quartz-crystal microbalance (QCM) technique was applied to investigate the interaction of tea catechins with lipid bilayers. The association constants obtained from the frequency changes of QCM revealed that (−)epicatechin gallate and (−)epigallocatechin gallate interacted with 1,2-dimyristoyl-sn-glycero-3-phosphocholine ca. 1000 times more strongly than (−)epicatechin and (−)epigallocatechin. The results exhibited good correlation with the strength of biological activity.
- Published
- 2008
33. Characterization of acrolein-induced protein cross-links
- Author
-
Tsutomu Nakayama, Takeshi Ishii, Taiki Mori, Shigenori Kumazawa, Koji Uchida, and Tomoe Yamada
- Subjects
medicine.medical_treatment ,Peptide ,Protein aggregation ,Tandem mass spectrometry ,Biochemistry ,Models, Biological ,Lipid peroxidation ,chemistry.chemical_compound ,Tandem Mass Spectrometry ,medicine ,Insulin ,Amino Acid Sequence ,Acrolein ,Peptide sequence ,Histidine ,Chromatography, High Pressure Liquid ,chemistry.chemical_classification ,Protease ,Binding Sites ,Proteins ,General Medicine ,Peptide Fragments ,Cross-Linking Reagents ,chemistry ,Lipid Peroxidation - Abstract
Lipid peroxidation products contribute to protein aggregation that occurs during oxidative stress in a number of degenerative disorders. Acrolein (ACR), a highly toxic lipid peroxidation aldehyde, is a strong cross-linking agent of cellular components such as proteins. To understand the mechanisms of oxidative stress-induced protein aggregation, this study characterized the ACR modification of chain B from bovine insulin by mass spectrometry. To identify the cross-linking sites, the ACR-treated peptide was digested with a protease and the resulting peptides were analysed by liquid chromatography-tandem mass spectrometry. Inter- and intra-molecular cross-linking adducts were identified between amino groups and the side chain of histidine in the peptide. These results indicated that the ACR-induced cross-links were accompanied by two reactions, namely Michael addition and Schiff base formation. In conclusion, the use of mass spectrometric techniques provided chemical evidence for protein cross-linking with ACR.
- Published
- 2007
34. Effects of β-Lactoglobulin on the Tight-junctional Stability of Caco-2-SF Monolayer
- Author
-
Kei Hashimoto, Makoto Shimizu, and Tsutomu Nakayama
- Subjects
Lactoglobulins ,Biology ,Applied Microbiology and Biotechnology ,Biochemistry ,Tight Junctions ,Analytical Chemistry ,chemistry.chemical_compound ,Animals ,Humans ,Cytoskeleton ,Molecular Biology ,Protein kinase C ,Cytochalasin D ,Phospholipase C ,Tight junction ,Organic Chemistry ,General Medicine ,Intracellular signal transduction ,chemistry ,Caco-2 ,Biophysics ,Cattle ,Caco-2 Cells ,Signal transduction ,Biotechnology - Abstract
The mechanisms for tight-junction (TJ) stabilization by beta-lactoglobulin (beta-Lg) were studied. Treatment of Caco-2-SF cells with inhibitors for some enzymes in the intracellular signal transduction pathways and a cytoskeleton-disturbing agent (cytochalasin D) reduced the TJ-stabilizing activity of beta-Lg. So beta-Lg is suggested to modulate the cytoskeletal structure through the activation of phospholipase C and protein kinase C, resulting in the TJ stabilization.
- Published
- 1998
35. Affinity of Antioxidative Polyphenols for Lipid Bilayers Evaluated with a Liposome System
- Author
-
Tsutomu Nakayama, Kei Hashimoto, and Koji Ono
- Subjects
Antioxidant ,Polymers ,Ubiquinone ,medicine.medical_treatment ,Lipid Bilayers ,Synthetic membrane ,Chick Embryo ,Applied Microbiology and Biotechnology ,Biochemistry ,Antioxidants ,Analytical Chemistry ,Phenols ,medicine ,Animals ,Lipid bilayer ,Molecular Biology ,Flavonoids ,Liposome ,Dose-Response Relationship, Drug ,Chemistry ,Organic Chemistry ,Polyphenols ,Biological activity ,General Medicine ,In vitro ,Membrane ,Polyphenol ,Liposomes ,Biotechnology - Abstract
We developed a method to measure the amounts of antioxidative polyphenols and ubiquinones incorporated into the liquid bilayers of liposomes to estimate their affinities for cell membranes. Results were expressed in terms of an "affinity factor", calculated by division of the amount of compound incorporated by the amount added to the liposomal solution. The results reflected dose-dependence of the biological activities of the compound found in earlier in vitro experiments with mammalian and bacterial cells.
- Published
- 1998
36. Mass spectroscopic characterization of protein modification by malondialdehyde
- Author
-
Tsutomu Nakayama, Shigenori Kumazawa, Takeshi Ishii, Toyo Sakurai, and Koji Uchida
- Subjects
Spectrometry, Mass, Electrospray Ionization ,Lysine ,Molecular Sequence Data ,Toxicology ,Peptide Mapping ,Epitope ,Adduct ,Lipid peroxidation ,chemistry.chemical_compound ,Malondialdehyde ,Animals ,Insulin ,Amino Acid Sequence ,Peptide sequence ,biology ,Serine Endopeptidases ,Antibodies, Monoclonal ,Proteins ,General Medicine ,Peptide Fragments ,Epitope mapping ,chemistry ,Biochemistry ,biology.protein ,Cattle ,Antibody ,Epitope Mapping - Abstract
Malondialdehyde (MDA), a naturally occurring dialdehyde produced in the membrane by lipid peroxidation, is a strong alkylating agent of primary amino groups. We recently raised a monoclonal antibody (mAb1F83) directed to the lipofuscin-like MDA--lysine adduct and demonstrated the presence of immunoreactivity to the antibody in the atherosclerotic lesions, in which intense positivity was associated primarily with macrophage-derived foam cells (Yamada et al., (2001) J. Lipid Res. 42, 1187-1196). To identify the structure of the epitope in the protein recognized by mAb1F83, in the present study, we exposed chain B from bovine insulin (insulin B chain) to MDA and characterized the MDA adducts by mass spectrometry. The MDA-modified insulin B chain was digested with V8 protease, and the resulting peptides were subjected to liquid chromatography--electrospray ionization--mass spectrometry (LC--ESI--MS/MS). The MS/MS analyses confirmed the formation of N-propenal- (+54 Da) and dihydropyridine-type (DHP, +134 Da) adducts in both Lys29 and the N-terminus of insulin B chain. The ELISA analysis of HPLC fractions of peptides, including the DHP adducts using mAb1F83, showed that the immunoreactivity of the DHP--lysine adduct was more significant than the DHP--N-terminus adduct. The results of this study chemically characterized that the MDA adducts such as DHP-type adducts generated in the epsilon-amino group of lysine and N-terminal amino acid residues in the protein and the structure of the epitope recognized by mAb1F83 were DHP--lysine adducts in protein.
- Published
- 2006
37. Inhibitory Effects of Caffeic Acid Ethyl Ester on H2O2-induced Cytotoxicity and DNA Single-strand Breaks in Chinese Hamster V79 Cells
- Author
-
Toshihiko Osawa, Shunro Kawakishi, Munetaka Yamada, and Tsutomu Nakayama
- Subjects
DNA damage ,Applied Microbiology and Biotechnology ,Biochemistry ,Chinese hamster ,Analytical Chemistry ,Structure-Activity Relationship ,chemistry.chemical_compound ,Caffeic Acids ,Cricetulus ,Cricetinae ,Caffeic acid ,Animals ,Drug Interactions ,Cytotoxicity ,Molecular Biology ,Cells, Cultured ,biology ,Chemistry ,Organic Chemistry ,food and beverages ,DNA ,Hydrogen Peroxide ,General Medicine ,Fibroblasts ,biology.organism_classification ,Cell culture ,Polyphenol ,Antimutagen ,DNA Damage ,Biotechnology - Abstract
Cytotoxicity and DNA single-strand breaks caused by H2O2 were assessed by a colony formation assay and a DNA precipitation assay, respectively, with Chinese hamster V79 cells. In both assays, caffeic acid ethyl ester showed protective effects. The structure-activity relationship showed that the o-dihydroxy structure of caffeic acid ethyl ester was essential for the protective effects.
- Published
- 1996
38. Direct evidence of interaction of a green tea polyphenol, epigallocatechin gallate, with lipid bilayers by solid-state Nuclear Magnetic Resonance
- Author
-
Satoru Tuzi, Michikazu Tanio, Akira Naito, Tsutomu Nakayama, Hazime Saitô, Shigenori Kumazawa, Eri Suzuki, Masayuki Suzuki, Fumio Nanjo, and Katsuko Kajiya
- Subjects
Magnetic Resonance Spectroscopy ,Lipid Bilayers ,Analytical chemistry ,Epigallocatechin gallate ,complex mixtures ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,chemistry.chemical_compound ,Phenols ,Molecule ,heterocyclic compounds ,Lipid bilayer ,Molecular Biology ,Flavonoids ,Liposome ,Tea ,Chemistry ,Bilayer ,Organic Chemistry ,food and beverages ,Polyphenols ,General Medicine ,Nuclear magnetic resonance spectroscopy ,Deuterium ,Crystallography ,Solid-state nuclear magnetic resonance ,lipids (amino acids, peptides, and proteins) ,sense organs ,Dimyristoylphosphatidylcholine ,Biotechnology - Abstract
The interaction of a tea catechin, epigallocatechin gallate (EGCg), with the model membrane of dimyristoylphosphatidylcholine (DMPC) was studied by solid-state (31)P and (2)H NMR. The (31)P chemical shift anisotropy of the DMPC phosphate group decreased on addition of EGCg. The (2)H NMR spectrum of [4-(2)H]EGCg, which is deuterated at the 4-position, in the DMPC liposomes gave deuterium nuclei with much smaller quadrupole splittings than those in the solid phase. These (31)P and (2)H NMR observations provide direct experimental evidence that the EGCg molecule interacts with the lipid bilayers.
- Published
- 2004
39. A new prenylated flavonoid from propolis collected in Okinawa, Japan
- Author
-
Shigenori Kumazawa, Tomoko Hamasaka, Hitomi Goto, Takunori Fujimoto, Syuichi Fukumoto, and Tsutomu Nakayama
- Subjects
Magnetic Resonance Spectroscopy ,Flavonoid ,Protein Prenylation ,Mass spectrometry ,Applied Microbiology and Biotechnology ,Biochemistry ,Propolis ,Analytical Chemistry ,Japan ,Picrates ,Molecular Biology ,chemistry.chemical_classification ,Flavonoids ,Chromatography ,Molecular Structure ,Chemistry ,Organic Chemistry ,Biphenyl Compounds ,General Medicine ,Free Radical Scavengers ,Prenylflavonoid ,Hydrazines ,Flavanones ,Two-dimensional nuclear magnetic resonance spectroscopy ,Biotechnology - Abstract
The new prenylflavonoid, isonymphaeol-B (1), together with three known compounds, nymphaeol-A (2), nymphaeol-B (3), and nymphaeol-C (4), were isolated from propolis collected in Okinawa, the southern-most prefecture of Japan. The structure of each compound was determined by spectral methods, including mass spectrometry and 2D NMR. Each compound had 1,1-diphenyl-2-picryl-hydrazyl radical-scavenging activity.
- Published
- 2004
40. Direct evidence for the plant origin of Brazilian propolis by the observation of honeybee behavior and phytochemical analysis
- Author
-
Masahiro Yoneda, Jun Kanaeda, Tsutomu Nakayama, Tomoko Hamasaka, Ikoi Shibata, and Shigenori Kumazawa
- Subjects
biology ,Behavior, Animal ,Baccharis ,Chemistry ,Plant Extracts ,General Chemistry ,General Medicine ,Propolis ,Bees ,biology.organism_classification ,Mass Spectrometry ,Apoidea ,Plant Leaves ,Ethanol extracts ,Baccharis dracunculifolia ,Aculeata ,Phytochemical ,Pollen basket ,Drug Discovery ,Botany ,Animals ,Brazil ,Chromatography, High Pressure Liquid - Abstract
To identify the plant origin of Brazilian propolis directly, we observed the behavior of honeybees in Minas Gerais State of Brazil. Honeybee workers bit and chewed leaves of the plant, Baccharis dracunculifolia, packed the material into their pollen basket, brought it back to their nest, and used it as propolis. We collected the leaves of B. dracunculifolia and propolis, and compared their constituents by liquid chromatography-mass spectrometry (LC/MS) analysis. There was no difference between the chemical constituents of the ethanol extracts of B. dracunculifolia and those of propolis. This indicates directly that the plant origin of Brazilian propolis is B. dracunculifolia.
- Published
- 2003
41. Identification of 6-methylsulfinylhexyl isothiocyanate as an apoptosis-inducing component in wasabi
- Author
-
Sumio Hayakawa, Tsutomu Nakayama, Makoto Watanabe, Mamoru Isemura, Masahiko Ohata, Naohide Kinae, Michiyo Furugori, and Shigenori Kumazawa
- Subjects
Wasabia ,Apoptosis ,Plant Science ,DNA Fragmentation ,Horticulture ,Pharmacognosy ,Biology ,Biochemistry ,chemistry.chemical_compound ,Isothiocyanates ,Stomach Neoplasms ,medicine ,Tumor Cells, Cultured ,Humans ,Molecular Biology ,Chromatography, High Pressure Liquid ,Plants, Medicinal ,U937 cell ,Dose-Response Relationship, Drug ,Cell growth ,Biological activity ,General Medicine ,U937 Cells ,medicine.disease ,Chromatin ,Leukemia ,chemistry ,Microscopy, Fluorescence ,Cell culture ,Isothiocyanate ,Leukemia, Monocytic, Acute ,Chromatography, Gel - Abstract
The ethanol extract from Japanese horseradish wasabi was found to inhibit cell proliferation in human monoblastic leukemia U937 cells by inducing apoptotic cell death. Separation by methods including silica gel chromatography and preparative HPLC gave an active compound, which was identified as 6-methylsulfinylhexyl isothiocyanate (6-HITC). Several lines of evidence indicated that 6-HITC induced apoptosis in U937 cells and human stomach cancer MKN45 cells. Thus, 6-HITC is potentially useful as a natural anti-cancer agent.
- Published
- 2003
42. Effects of external factors on the interaction of tea catechins with lipid bilayers
- Author
-
Tsutomu Nakayama, Katsuko Kajiya, and Shigenori Kumazawa
- Subjects
Lipid Bilayers ,Static Electricity ,Synthetic membrane ,Sodium Chloride ,complex mixtures ,Applied Microbiology and Biotechnology ,Biochemistry ,Catechin ,Analytical Chemistry ,Phosphates ,chemistry.chemical_compound ,Structure-Activity Relationship ,Static electricity ,Lipid bilayer ,Molecular Biology ,Liposome ,Chromatography ,Tea ,Chemistry ,Bilayer ,Organic Chemistry ,food and beverages ,Stereoisomerism ,General Medicine ,Gallate ,Membrane ,Spectrometry, Fluorescence ,Hydrophobic and Hydrophilic Interactions ,Biotechnology - Abstract
Green tea contains a high concentration of such catechins as (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg). Their biological activities have been evaluated by in vitro experiments using cultured cells or bacteria, but the order of activity of the various catechins differed with the study. We have been studying the interaction of tea catechins with lipid bilayers, and clarified that the number of hydroxyl groups on the B-ring, the presence of the galloyl moiety, and the stereochemical structure of each catechin govern their affinity for lipid bilayers. We investigated in this present study the effects of various external factors on the affinity of tea catechins for lipid bilayers by using liposomes as model membranes. The amount of tea catechins incorporated into the lipid bilayers increased with increasing salt concentration in an aqueous medium and decreased with increasing negative electric charge of the lipid bilayers. Furthermore, the amount of EGCg or ECg incorporated into the lipid bilayers increased with increasing EC concentration. These results reveal that the salt concentration in an aqueous medium, the electric charge of the membrane, and the presence of other catechins governed the affinity of tea catechins for the lipid bilayers.
- Published
- 2003
43. Suppression of Hydrogen Peroxide-induced Cytotoxicity toward Chinese Hamster Lung Fibroblasts by Decylubiquinone, a Coenzyme Q Homolog
- Author
-
Yukie Ogiso, Shunro Kawakishi, Tsutomu Nakayama, and Toshihiko Osawa
- Subjects
inorganic chemicals ,Antioxidant ,medicine.medical_treatment ,Organic Chemistry ,Hamster ,General Medicine ,Oxidative phosphorylation ,Biology ,biology.organism_classification ,Applied Microbiology and Biotechnology ,Biochemistry ,Chinese hamster ,Analytical Chemistry ,chemistry.chemical_compound ,chemistry ,Coenzyme Q – cytochrome c reductase ,medicine ,Coenzyme analog ,Hydrogen peroxide ,Cytotoxicity ,Molecular Biology ,Biotechnology - Abstract
The cytotoxicity of hydrogen peroxide (H2O2) toward Chinese hamster V79 cells was assessed with a colony-formation assay. Decylubiquinone, a coenzyme Q homolog, suppressed H2O2-induced cytotoxicity. Almost all the incorporated decylubiquinone was detected as decylubiquinol after incubating the cells for 4h. These results suggest that decylubiquinol reduced in the cells acted as an antioxidant against H2O2-induced oxidative cell injury.
- Published
- 1994
44. Antioxidative and Prooxidative Activity of Caffeic Acid toward H2O2-induced DNA Strand Breakage Dependent on the State of the Fe Ion in the Medium
- Author
-
Takahiro Kung, Masanori Hiramitsu, Shunro Kawakishi, Tsutomu Nakayama, and Toshihiko Osawa
- Subjects
Antioxidant ,biology ,Chemistry ,Stereochemistry ,medicine.medical_treatment ,Cytochrome c ,Organic Chemistry ,Biological activity ,General Medicine ,Applied Microbiology and Biotechnology ,Biochemistry ,Dna strand breakage ,Analytical Chemistry ,Ion ,chemistry.chemical_compound ,Polyphenol ,medicine ,Caffeic acid ,biology.protein ,Biophysics ,Molecular Biology ,DNA ,Biotechnology - Published
- 1993
45. Lipid peroxidation in linoleic acid micelles caused by H2O2 in the presence of myoglobin
- Author
-
Kei Hashimoto, Youhei Chiba, and Tsutomu Nakayama
- Subjects
Linoleic acid ,Iron Chelating Agents ,Applied Microbiology and Biotechnology ,Biochemistry ,Ferric Compounds ,Antioxidants ,Analytical Chemistry ,Lipid peroxidation ,Linoleic Acid ,chemistry.chemical_compound ,Oxygen Consumption ,Hydrogen peroxide ,Sodium nitrite ,Molecular Biology ,Unsaturated fatty acid ,Micelles ,Chromatography ,Sodium Nitrite ,Myoglobin ,Organic Chemistry ,General Medicine ,Hydrogen Peroxide ,Pentetic Acid ,Ascorbic acid ,Trimethyl Ammonium Compounds ,Quaternary Ammonium Compounds ,chemistry ,Metmyoglobin ,Linoleic Acids ,Lipid Peroxidation ,Biotechnology - Abstract
We investigated the lipid peroxidation in linoleic acid micells caused by H2O2 in the presence of metmyoglobin by monitoring the oxygen consumption. O2 consumption usually consisted of two phases. In the first phase, it occurred slowly and linearly until the concentration of linoleic acid hydroperoxide reached a certain value, rapid consumption, presumably by a chain reaction, then followed in the second phase. No effects of diethylenetriaminepentaacetic acid (DTPA) on the induction period (the period during the first phase) and the maximum oxygen consumption rate (MOCR) in the second phase indicate that free ferric ions liberated from myoglobin had no role in any phases during the lipid peroxidation. The differing dose effects of ascorbic acid, alpha-tocopherol, and sodium nitrite on the induction period and MOCR reflect their respective antioxidative mechanisms during lipid peroxidation.
- Published
- 1997
46. Antioxidative and antimutagenic effects of theaflavins from black tea
- Author
-
Toshihiko Osawa, Yukihiko Hara, Harue Kumon, Mayumi Shiraki, Shunro Kawakishi, and Tsutomu Nakayama
- Subjects
Antioxidant ,medicine.medical_treatment ,DNA, Single-Stranded ,In Vitro Techniques ,Antioxidants ,Catechin ,Lipid peroxidation ,chemistry.chemical_compound ,medicine ,Animals ,Biflavonoids ,Gallic acid ,Theaflavin ,Biotransformation ,Tea ,Erythrocyte Membrane ,food and beverages ,Antimutagenic Agents ,General Medicine ,Hydrogen Peroxide ,Rats ,Biochemistry ,chemistry ,Polyphenol ,Microsomes, Liver ,Lipid Peroxidation ,Rabbits ,Antimutagen ,Mutagens - Abstract
Theaflavins, polyphenolic ingredients of black tea, were observed to inhibit in vitro lipid peroxidation in the erythrocyte membrane ghost and microsomal systems. Theaflavins also showed inhibition of DNA single-strand cleavage and mutagenicity, both induced by hydrogen peroxide. These results suggest that theaflavins scavenge radicals to produce antioxidative and antimutagenic effects. It was also found that the gallic acid moiety of theaflavins is essential for their potent antioxidative activities.
- Published
- 1994
47. The protective role of gallic acid esters in bacterial cytotoxicity and SOS responses induced by hydrogen peroxide
- Author
-
Toshihiko Osawa, Masanori Hiramitsu, Tsutomu Nakayama, and Shunro Kawakishi
- Subjects
Salmonella typhimurium ,Salmonella ,Chemistry ,Mutagenicity Tests ,Revertant ,Esters ,General Medicine ,Hydrogen Peroxide ,medicine.disease_cause ,Ames test ,SOS chromotest ,chemistry.chemical_compound ,Structure-Activity Relationship ,Biochemistry ,Gallic Acid ,medicine ,Escherichia coli ,Gallic acid ,SOS response ,Hydrogen peroxide ,Cytotoxicity ,SOS Response, Genetics - Abstract
The effects of gallic acid and its esters on H2O2-induced cytotoxicity, mutagenicity and SOS response were investigated in bacterial assay systems, i.e., the Ames test with Salmonella typhimurium TA104 and the SOS chromotest with E. coli PQ37. In the Ames test, gallic acid esters showed protective effects against H2O2-induced cytotoxicity and no effects on the number of revertant colonies. In the SOS chromotest, gallic acid esters lowered the SOS induction factor raised by H2O2. Throughout the study, the effects of gallic acid itself were weak or negligible, and lauryl gallate was most effective among the three gallic acid esters. This structure-activity relationship indicates the similarity of the protective effects of gallic acid esters on the H2O2-induced damages to both bacterial and mammalian cells.
- Published
- 1993
48. Stabilization of the Tight Junction of the Intestinal Caco-2 Cell Monolayer by Milk Whey Proteins
- Author
-
Kei Hashimoto, Makoto Shimizu, Tsutomu Nakayama, and Kyoko Takeda
- Subjects
Whey protein ,Cell Membrane Permeability ,Cell ,Serum albumin ,Lactoglobulins ,Applied Microbiology and Biotechnology ,Biochemistry ,Tight Junctions ,Analytical Chemistry ,Monolayer ,medicine ,Animals ,Humans ,Trypsin ,Intestinal Mucosa ,Bovine serum albumin ,Molecular Biology ,biology ,Tight junction ,Chemistry ,Organic Chemistry ,Serum Albumin, Bovine ,General Medicine ,Milk Proteins ,Milk ,Whey Proteins ,medicine.anatomical_structure ,Caco-2 ,Cell culture ,biology.protein ,Biophysics ,Cattle ,Caco-2 Cells ,Biotechnology - Abstract
The tight junction (TJ) of the human intestinal Caco-2-SF monolayer was shown not to have been stably formed. TJ was stabilized by incubating the cell monolayer with beta-lactoglobulin (beta-Lg) and bovine serum albumin (BSA). Thus, the Caco-2-SF cell-culture system will provide a useful model for studying the factors which stabilize TJ and for investigating the mechanism of TJ regulation.
- Published
- 1995
49. Generation of hydrogen peroxide and superoxide anion from active metabolites of naphthylamines and aminoazo dyes: its possible role in carcinogenesis
- Author
-
Tsutomu Nakayama, Chikayoshi Nagata, Masahiko Kodama, and Temyuki Kimura
- Subjects
Cancer Research ,Free Radicals ,Radical ,Naphthalenes ,Medicinal chemistry ,Superoxide dismutase ,chemistry.chemical_compound ,Naphthylamine ,Superoxides ,Animals ,Hydrogen peroxide ,chemistry.chemical_classification ,Reactive oxygen species ,Autoxidation ,biology ,Superoxide ,Superoxide Dismutase ,General Medicine ,Hydrogen Peroxide ,Oxygen ,chemistry ,Catalase ,biology.protein ,Cattle ,Spectrophotometry, Ultraviolet ,Azo Compounds - Abstract
Autoxidation of active metabolites of naphthylamine and aminoazo dyes in neutral buffer generated hydrogen peroxide (H2O2) and superoxide anion (O-.2), as detected by the titanium sulfate method and nitro blue tetrazolium method, respectively. 2-Amino-1-naphthol, 1-amino-2-naphthol, 1-amino-4-naphthol, N-hydroxy-2-aminonaphthalene, N-hydroxy-1-aminonaphthalene, N-hydroxy-4-aminoazobenzene and N-hydroxy-4-methylaminoazobenzene generated H2O2 and O-.2, whereas 1-nitrosonaphthalene, 2-nitrosonaphthalene, 1-naphtylamine, 2-naphthylamine and non-carcinogenic aminonaphthols and naphthols generated no active oxygens. Catalase and superoxide dismutase were used to identify the formation of these active oxygens. For all compounds tested except nitrosonaphthalenes, good parallelism was found between the active oxygen formation and convertibility to free radicals. These results suggest a possible role of free radicals and subsequently formed active oxygens in aromatic amine carcinogenesis.
- Published
- 1983
Catalog
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