37 results on '"Tsutomu Nakayama"'
Search Results
2. 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.
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- 2022
3. Enhanced sugar chain detection by oriented immobilization of Fc-fused lectins
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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
4. Theaflavin-3-gallate specifically interacts with phosphatidylcholine, forming a precipitate resistant against the detergent action of bile salt
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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
5. Specificity of tyrosinase-catalyzed synthesis of theaflavins
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Tsutomu Nakayama, Asako Narai-Kanayama, Yuuka Uchida, Aya Kawashima, and Miho Kawamura
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0301 basic medicine ,chemistry.chemical_classification ,Catechol ,030102 biochemistry & molecular biology ,Process Chemistry and Technology ,Tyrosinase ,Substrate (chemistry) ,Bioengineering ,Catechin ,Biochemistry ,Redox ,Catalysis ,Quinone ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Enzyme ,chemistry ,Organic chemistry ,Theaflavin - Abstract
This study kinetically characterized the mechanism of the enzymatic synthesis of theaflavins (TFs) from catechins by mushroom tyrosinase (EC 1.14.18.1). In reactions containing one of four catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), and their galloylated forms (ECg and EGCg), they were oxidized by tyrosinase with apparent KM values of 3.78, 5.55, 0.80, and 3.05 mM, respectively, and with different consumption rates, of which EC was more than four times higher than those of the others. In reactions with binary combinations of catechins with tyrosinase, the synthesis of TF1 from EC and EGC occurred most efficiently, while the yields of mono- and di-galloylated TFs, TF2A, TF2B, and TF3, were low. Time-dependent changes in concentrations of the reactants suggested that the enzymatic oxidation of catechins and the subsequent non-enzymatic coupling redox reaction between the quinone derived from EC or ECg and the intact pyrogallol-type catechin (EGC or EGCg) proceeded concurrently. The latter reaction induced the rapid decrease of EGC and EGCg and it was remarkable for EGCg. So the efficiency of condensation of a pair of quinones from catechol- and pyrogallol-type catechins is restricted, critically influencing the yield of TFs. Using green tea extracts as mixtures of the four substrate catechins, tyrosinase produced TF1 most abundantly. Furthermore, a remarkable enhancement of production of TF2A and TF2B as well as TF1 was observed, when the initial concentration of EGCg was low. These results suggest that the catechin composition has an impact on yields of TFs.
- Published
- 2016
6. 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
- Author
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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.
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- 2011
7. Structural characteristics of green tea catechins for formation of protein carbonyl in human serum albumin
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Tatsuya Ichikawa, Toshiyuki Wakimoto, Takeshi Ishii, Yoshiyuki Aihara, Yoshinori Uekusa, Tsutomu Nakayama, Koji Kusaka, Toshiyuki Kan, Taiki Mori, Maiko Kaku, Mitsugu Akagawa, and Takumi Furuta
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Stereochemistry ,Chemical structure ,Protein Carbonylation ,Clinical Biochemistry ,Flavonoid ,Serum albumin ,Pharmaceutical Science ,Pyrogallol ,Biochemistry ,Catechin ,chemistry.chemical_compound ,Drug Discovery ,medicine ,Humans ,Molecular Biology ,Serum Albumin ,chemistry.chemical_classification ,Molecular Structure ,Tea ,biology ,Organic Chemistry ,Human serum albumin ,chemistry ,Polyphenol ,biology.protein ,Molecular Medicine ,medicine.drug - Abstract
Catechins are polyphenolic antioxidants found in green tea leaves. Recent studies have reported that various polyphenolic compounds, including catechins, cause protein carbonyl formation in proteins via their pro-oxidant actions. In this study, we evaluate the formation of protein carbonyl in human serum albumin (HSA) by tea catechins and investigate the relationship between catechin chemical structure and its pro-oxidant property. To assess the formation of protein carbonyl in HSA, HSA was incubated with four individual catechins under physiological conditions to generate biotin-LC-hydrazide labeled protein carbonyls. Comparison of catechins using Western blotting revealed that the formation of protein carbonyl in HSA was higher for pyrogallol-type catechins than the corresponding catechol-type catechins. In addition, the formation of protein carbonyl was also found to be higher for the catechins having a galloyl group than the corresponding catechins lacking a galloyl group. The importance of the pyrogallol structural motif in the B-ring and the galloyl group was confirmed using methylated catechins and phenolic acids. These results indicate that the most important structural element contributing to the formation of protein carbonyl in HSA by tea catechins is the pyrogallol structural motif in the B-ring, followed by the galloyl group. The oxidation stability and binding affinity of tea catechins with proteins are responsible for the formation of protein carbonyl, and consequently the difference in these properties of each catechin may contribute to the magnitude of their biological activities.
- Published
- 2010
8. 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.
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- 2010
9. 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
10. 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
11. Dynamic Behavior of Tea Catechins Interacting with Lipid Membranes As Determined by NMR Spectroscopy
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Miya Kamihira, Yoshinori Uekusa, and Tsutomu Nakayama
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chemistry.chemical_classification ,Magnetic Resonance Spectroscopy ,Tea ,Lipid Bilayers ,Flavonoid ,Catechin ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,Epigallocatechin gallate ,Structure-Activity Relationship ,chemistry.chemical_compound ,Membrane ,Epicatechin gallate ,chemistry ,Polyphenol ,Organic chemistry ,General Agricultural and Biological Sciences ,Lipid bilayer - Abstract
Interaction between tea catechins, such as epicatechin gallate (ECg) and epigallocatechin gallate (EGCg), and isotropic bicelle model lipid membranes was investigated by solution NMR techniques. (1)H NMR measurements provided signals from the B-ring and the galloyl moiety in ECg and EGCg that were obviously shifted, and whose proton T1 relaxation times were shortened upon interaction of the catechins with the bicelles. These results indicate that the B-ring and the galloyl moiety play an important role in this interaction. Nuclear Overhauser effect spectrometry experiments demonstrated that the B-ring and the galloyl moiety are located near the gamma-H in the phospholipid trimethylammonium group. On the basis of these findings, we propose that ECg and EGCg interact with the surface of lipid membranes via the choline moiety.
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- 2007
12. 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.
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- 2004
13. Studies of the Constituents of Uruguayan Propolis
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Shigenori Kumazawa, Katsumi Hayashi, Tsutomu Nakayama, Katsuko Kajiya, Tomoko Hamasaka, and Takeshi Ishii
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Chemical structure ,Carboxylic acid ,Flavonoid ,Carboxylic Acids ,Ethyl acetate ,Acetates ,Spectrometry, Mass, Fast Atom Bombardment ,Propolis ,chemistry.chemical_compound ,Anti-Infective Agents ,Phenols ,Chinese origin ,Organic chemistry ,Chromatography, High Pressure Liquid ,Flavonoids ,chemistry.chemical_classification ,Ethanol ,Traditional medicine ,Pinobanksin ,General Chemistry ,Phenolic acid ,Solubility ,chemistry ,Flavanones ,Uruguay ,General Agricultural and Biological Sciences - Abstract
Eighteen flavonoids including two new compounds, four aromatic carboxylic acids, and eleven phenolic acid esters including one new compound were isolated and identified from the ethyl acetate soluble fraction of the 70% ethanol extract of Uruguayan propolis. The new compounds were elucidated as pinobanksin 3-(2-methyl)butyrate (1; recently reported in Usia, T.; Banskota, A. H.; Tezuka, Y.; Midorikawa, K.; Matsushige, K.; Kadota, S. J. Nat. Prod. 2002, 65, 673-676) pinobanksin 3-isobutyrate (2), and 2-methyl-2-butenyl ferulate (24). The constituents isolated from Uruguayan propolis in this study were similar to those of propolis of European and Chinese origin. Thus, it is suggested that the Uruguayan propolis has a plant origin similar to those of propolis from Europe and China.
- Published
- 2002
14. The human bitter taste receptor hTAS2R39 is the primary receptor for the bitterness of theaflavins
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Noriko Matsuda, Tsutomu Nakayama, Tatsuo Watanabe, Toyomi Yamazaki, Riko Ikeda, Toshiyuki Nakamura, Takeshi Ishii, and Miki Sagisaka
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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
15. Steric Effects on Interaction of Tea Catechins with Lipid Bilayers
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Shigenori Kumazawa, Tsutomu Nakayama, and Katsuko Kajiya
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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
16. Interaction of Tea Catechins with Lipid Bilayers Investigated with Liposome Systems
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Fumio Nanjo, Yukihiko Hara, Toshihiko Hashimoto, Tsutomu Nakayama, and Shigenori Kumazawa
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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
17. Superoxide Dismutase Inhibition of Oxidation of Ubiquinol and Concomitant Formation of Hydrogen Peroxide
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Tsutomu Nakayama, Miku Hashimoto, and Kei Hashimoto
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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
18. Antioxidative Effects of Phenolic Acids on Lipid Peroxidation Induced by H2O2 in the Presence of Myoglobin
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Tsutomu Nakayama, Shigenori Kumazawa, Kei Hashimoto, Mayuko Sato, and Katsuko Kajiya
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Marketing ,Antioxidant ,Chromatography ,General Chemical Engineering ,Linoleic acid ,medicine.medical_treatment ,chemistry.chemical_element ,Micelle ,Oxygen ,Industrial and Manufacturing Engineering ,Ferulic acid ,Lipid peroxidation ,chemistry.chemical_compound ,Metmyoglobin ,chemistry ,medicine ,Caffeic acid ,Organic chemistry ,Food Science ,Biotechnology - Abstract
Antioxidant effects of the phenolic acids, caffeic acid, p-coumaric acid, and ferulic acid, were investigated by monitoring O2 consumption in the linoleic acid micelles in the presence of H2O2 and metmyoglobin. O2 consumption usually consists of two phases: In the first phase, O2 is consumed slowly until the concentration of linoleic acid hydroperoxide reaches a certain value; then in the second phase O2 is consumed rapidly. At pH 7.4, the phenolic acids prolonged the period of the first phase and showed no effect on the second phase. At pH 3.4, the phenolic acids decreased the oxygen consumption rate in the second phase. These results suggest that the main antioxidant effects of the phenolic acids should be ascribed to reduction of ferrylmyoglobin in the first phase at pH 7.4 and inhibition of the chain reaction occurring inside of the micelles in the second phase at pH 3.4.
- Published
- 2004
19. Human serum albumin as an antioxidant in the oxidation of (-)-epigallocatechin gallate: participation of reversible covalent binding for interaction and stabilization
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Mitsugu Akagawa, Kanako Minoda, Tsutomu Nakayama, Toshinao Goda, Yukiko Suzuki, Kazuki Mochizuki, Koji Kusaka, Tatsuya Ichikawa, Sohei Ito, and Takeshi Ishii
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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
20. Antioxidant activity of pea bean (Phaseolus vulgaris L.) extract
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Takanori Tsuda, Katsumi Ohshima, Shunro Kawakishi, Toshihiko Osawa, and Tsutomu Nakayama
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Chromatography ,Antioxidant ,biology ,Thiocyanate ,General Chemical Engineering ,Linoleic acid ,medicine.medical_treatment ,Organic Chemistry ,food and beverages ,Biological activity ,biology.organism_classification ,chemistry.chemical_compound ,chemistry ,Distilled water ,Ninhydrin ,medicine ,Methanol ,Phaseolus - Abstract
Antioxidative activity of pea bean (Phaseolus vulgaris L.) extract was evaluated by using a linoleic acid system, and the methanol extract exhibited strong antioxidative activity as measured by the thiocyanate method. The crude methanol extract was partitioned between then-butanol phase (BP) and the water phase (WP). Then, the antioxidative activity of the BP and the WP was determined by using a linoleic acid system. The WP showed strong antioxidative activity, while BP showed only weak activity as measured by the thiocyanate method. Next, the synergistic antioxidative action of WP with α-tocopherol was examined by using linoleic acid and liposome systems. The WP had a synergistic effect with α-tocopherol in both the food model and liposome systems. For purification and isolation of the antioxidative substances of the pea bean, preparative high-performance liquid chromatography was carried out with an octadecylsilyl column. Five fractions were collected, and antioxidative activity was determined in a linoleic acid system. Although fraction 1 had strong activity by the thiocyanate method, the purification of this active fraction was difficult; therefore, the partly characterized active fraction was investigated. The contents of total phenolics and sugars were 0.31±0.01 mg/g of fraction 1 and 406.1±0.1 mg/g, respectively. The ninhydrin chromogenic reaction was positive, and the ultraviolet absorption spectral λ max value in distilled water was 264.0 nm, indicating that the water-soluble antioxidative components from pea bean may be a new type of antioxidant. Isolation and identification are currently being investigated.
- Published
- 1993
21. Covalent binding of tea catechins to protein thiols: the relationship between stability and electrophilic reactivity
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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
22. 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
23. 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
24. 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
25. 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
26. 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
27. 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
28. 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
29. 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
30. 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
31. 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
32. Apoptosis-inducing activity of galloyl monosaccharides in human histiocytic lymphoma U937 cells
- Author
-
Shigenori Kumazawa, Sumio Hayakawa, Yoshiyuki Nakamura, Tsutomu Nakayama, Ken-ichi Tanji, Kouichi Saeki, Mamoru Isemura, Tadataka Noro, and Toshio Miyase
- Subjects
Pharmaceutical Science ,Apoptosis ,Biology ,Analytical Chemistry ,chemistry.chemical_compound ,Gallic Acid ,Drug Discovery ,Monosaccharide ,Humans ,Cytotoxicity ,Pharmacology ,chemistry.chemical_classification ,U937 cell ,Organic Chemistry ,Monosaccharides ,Biological activity ,U937 Cells ,Molecular biology ,Antineoplastic Agents, Phytogenic ,In vitro ,Complementary and alternative medicine ,chemistry ,Biochemistry ,Cell culture ,Molecular Medicine ,Lymphoma, Large B-Cell, Diffuse ,DNA - Abstract
Three galloyl monosaccharides contained in medicinal plants were examined for apoptosis-inducing activity in human histiocytic lymphoma U937 cells. Tetragalloyl glucose (TgG) induced apoptosis as found by chromatin condensation, DNA ladder formation, and inhibition by a caspase inhibitor. Digalloyl hamamelose had moderate activity, while monogalloyl glucose was only marginally active. These findings suggest that the number and disposition of their phenolic groups are important for apoptosis induction. TgG induced apoptosis in human colon and stomach cancer cell lines as well, indicating it is potentially useful as an anti-cancer agent.
- Published
- 2000
33. 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
34. Mechanisms generating hydrogen peroxide in an aqueous extract of cigarette smoke: The promoting effect of aniline
- Author
-
Y. Takanami and Tsutomu Nakayama
- Subjects
Aqueous extract ,chemistry.chemical_compound ,Aniline ,chemistry ,Physiology (medical) ,Organic chemistry ,Cigarette smoke ,Hydrogen peroxide ,Biochemistry - Published
- 2012
35. 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
36. New Synthesis of the Both Enantiomers of (Z)-5-(1-Decenyl)-oxacyclopentan-2-one, the Pheromone of the Japanese Beetle
- Author
-
Kazuo Sato, Tsutomu Nakayama, and Kenji Mori
- Subjects
chemistry.chemical_classification ,biology ,Stereochemistry ,Japanese beetle ,Chemistry ,biology.organism_classification ,General Biochemistry, Genetics and Molecular Biology ,Japonica ,Popillia ,Pheromone ,Organic chemistry ,Enantiomer ,General Agricultural and Biological Sciences ,Lactone - Abstract
The both enantiomers of (Z)-5-(1-decenyl)oxacyclopentan-2-one were synthesized starting from resolved acetylenic intermediates. The (R)-form of this lactone is the pheromone of Popillia japonica. The optical purities of the final products were about 90%.
- Published
- 1979
37. Volatile and Nonvolatile Maillard Reaction Products between<scp>l</scp>-Lysine and<scp>d</scp>-Glucose
- Author
-
Hiromichi Kato, Shigeji Sugimoto, Fumitaka Hayase, and Tsutomu Nakayama
- Subjects
Maillard reaction ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,D-Glucose ,Lysine ,symbols ,Organic chemistry ,General Agricultural and Biological Sciences ,General Biochemistry, Genetics and Molecular Biology - Published
- 1982
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