Toshihiko Osawa

Kyoto Prefectural University of Medicine, Kyoto, Kyoto-fu, Japan

Are you Toshihiko Osawa?

Claim your profile

Publications (290)742.68 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We had isolated an O-desmethylangolensin (O-DMA)-producing bacterium, Clostridium rRNA cluster XIVa strain SY8519. According to chiral separation using HPLC, the SY8519-produced O-DMA exhibited high optical purity. To determine the absolute stereochemistry of O-DMA, we prepared 2-(4-hydroxyphenyl)propionic acid (2-HPPA) from the O-DMA using the Baeyer–Villiger reaction. From chiral analysis of the product, the major peak had the same stereochemistry to that of 2-HPPA produced from genistein by the same bacteria. As we have determined the stereochemistry of SY8519-produced 2-HPPA to have an R configuration, by the chemical synthesis of (S)-2-HPPA, the SY8519-produced O-DMA must also possess R stereochemistry at the 2-position. To study the stereoselective metabolism, we applied racemic dihydrodaidzein to SY8519. The O-DMA was isolated from the culture media and starting material was also recovered. The O-DMA produced was optically active in a similar manner to that produced from daidzein. However, the remaining dihydrodaidzein exhibited no difference between the enantiomers. These results suggested that SY8519 produces (R)-O-DMA from both enantiomers of dihydrodaidzein.
    Food Chemistry 03/2015; 171:153–156. · 3.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Nervous system controls all the organs in the living like a symphony. In this chapter, the mechanism of neuronal death in aged is discussed in relation to oxidative stress. Polyunsaturated fatty acid (PUFA) is known to be rich in the membranous component of the neurons and plays an important role in maintaining the neuronal functions. Recent reports revealed that oxidation of omega-3 and omega-6 PUFAs, such as docosahexaenoic acid (DHA) and arachidonic acid (ARA), are potent antioxidant but simultaneously, their oxidation products are potentially toxic. In this chapter, the existence of early oxidation products of PUFA is examined in the samples from neurodegenerative disorders and the cellular model. Accumulation of proteins with abnormal conformation is suggested to induce neuronal death by disturbance of proteolysis and mitochondrial function. The role of lipid peroxide and lipid-derived aldehyde adduct proteins is discussed in relation to brain ageing and age-related neurodegeneration.
    Sub-cellular biochemistry 01/2014; 77:127-36.
  • Shinsuke Hisaka, Toshihiko Osawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Phospholipids such as phosphatidylethanolamine and phosphatidylcholine play crucial roles in the biological system to maintain the cellular environmental condition. Despite that, oxidative stress targets these phospholipids containing polyunsaturated fatty acids and accompanies the oxidized phospholipids. Recent studies have been suggested that oxidized phospholipids have the relationship with inflammation and might induce the atherosclerosis formation by uptake of oxidized LDL through scavenger receptor as ligands. Red blood cells, which have been studied the bilayer model, are also modified by oxidative stress because hemoglobin can mediate and produce the reactive oxygen species, which leads to lipid peroxidation of biomembrane. In these oxidation processes of biomolecules, hexanoylation against phosphatidylethanolamine and phosphatidylserine, which has the primary amine and is the target of this modification, generates the oxidized membrane such as erythrocyte ghosts. This unique structure of phosphatidylethanolamine and phosphatidylserine is possibly the useful biomarker to evaluate the oxidation of biomembrane in vivo using liquid chromatography tandem mass spectrometry and monoclonal antibody.
    Sub-cellular biochemistry 01/2014; 77:41-8.
  • Xuebo Liu, Naruomi Yamada, Toshihiko Osawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Dopamine is the endogenous neurotransmitter produced by nigral neurons. Dopamine loss can trigger not only prominent secondary morphological changes, but also changes in the density and sensitivity of dopamine receptors; therefore, it is a sign of PD development. The reasons for dopamine loss are attributed to dopamine's molecular instability due to it is a member of catecholamine family, whose catechol structure contributes to high oxidative stress through enzymatic and non-enzymatic oxidation. Oxidative stress in the brain easily leads to the lipid peroxidation reaction due to a high concentration of polyunsaturated fatty acids (PUFA), such as docosahexaenoic acid (DHA, C22:6/ω-3) and arachidonic acid (AA, C18:4/ω-6). Recent studies have shown that lipid hydroperoxides, the primary peroxidative products, could non-specifically react with primary amino groups to form N-acyl-type (amide-linkage) adducts. Therefore, based on the NH2-teminals in dopamine's structure, the aims of this chapter are to describes the possibility that reactive LOOH species derived from DHA/AA lipid peroxidation may modify dopamine to form amide-linkage dopamine adducts, which might be related to etiology of Parkinson's diseases.
    Sub-cellular biochemistry 01/2014; 77:49-60.
  • Toshio Niwa, Shin-Ichiro Yokoyama, Toshihiko Osawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Soy isoflavonoids have many useful properties. However, they are metabolized in vivo, including in humans. The effect of the metabolism of soy isoflavonoids on their properties is not fully understood. We have isolated the bacterial strain SY8519, which has been shown to metabolize daidzein to O-desmethylangolensin and to produce 2-(4-hydroxyphenyl)propionic acid from genistein. According to chiral HPLC analysis, the 2-(4-hydroxyphenyl)propionic acid obtained from the bacterium was optically active. To determine the absolute stereochemistry of the microbial product, we prepared (S)-2-(4-hydroxyphenyl)propionic acid from (S)-2-phenylpropionic and concluded that the microbial product had an R-configuration by chiral HPLC analysis. We also applied the metabolite to mouse adipocytes and found that 2-HPPA was less effective at reducing leptin secretion than the parent compound genistein. Our results suggested that 'O-desmethylangolensin-production' attenuates the effect of soy isoflavonoids by reducing not only the activity of daidzein but also that of genistein.
    Food Chemistry 05/2013; 138(1):122-5. · 3.33 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Photoageing of skin is thought to be caused by protein denaturation, which can be induced by ultraviolet radiation. Previous studies have also reported that inflammation is related to protein denaturation; however, the influence of inflammation on skin ageing has not been explored in detail. To investigate the possible connection between inflammation and protein denaturation, which might lead to skin ageing, we focused on halogenated tyrosine as a denatured substance produced during the inflammation process. We measured halogenated tyrosine in aged human skin. Inflammatory cells and halogenated tyrosine were detected by immunohistochemistry using antibodies to mast-cell tryptase, neutrophilic myeloperoxidase and halogenated tyrosine. Finally, using elastic van Gieson (EVG) staining, we investigated whether the sites of halogenated tyrosine coincided with the sites at which proteins were denatured. Immunohistochemical analysis indicated that both inflammatory cells and halogenated tyrosines increased with ageing in both photoexposed and photoprotected skin. EVG staining confirmed that the localization of halogenated tyrosine was close to the sites at which protein was denatured. Our investigations indicate a possible connection between skin ageing and inflammation, suggesting that halogenated tyrosine could be a useful marker of ageing skin.
    Clinical and Experimental Dermatology 04/2012; 37(3):252-8. · 1.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: N(ε)-(Hexanoyl)lysine, formed by the reaction of lysine with n-6 lipid hydroperoxide, is a lipid peroxidation marker during the initial stage of oxidative stress. The aim of the present study is to indentify N(ε)-(hexanoyl)lysine-modified proteins in neoplastic transformed gastric mucosal cells by N-methyl-N'-nitro-N-nitrosoguanidine, and to compare the levels of these proteins between gastric mucosal cells and normal gastric cells. Much greater fluorescence of 2-[6-(4'-hydroxy)phenoxyl-3H-xanthen-3-on-9-yl]benzoic acid, an index of the intracellular levels of reactive oxygen species, was observed for gastric mucosal cells compared to normal gastric cells. N(ε)-(Hexanoyl)lysine-modified proteins were detected by SDS-PAGE or two-dimensional electrophoresis and Western blotting using anti-N(ε)-(hexanoyl)lysine polyclonal antibody, and a protein band of between 30-40 kDa was clearly increased in gastric mucosal cells compared to normal gastric cells. Two N(ε)-(hexanoyl)lysine-modified protein spots in gastric mucosal cells were identified as the tropomyosin 1 protein by mass spectrometry using a MASCOT search. The existence of N(ε)-(hexanoyl)lysine modification in tropomyosin 1 was confirmed by Western blotting of SDS-PAGE-separated or two-dimensional electrophoresis-separated proteins as well as by the immunoprecipitation with anti-tropomyosin 1 antibody. These data indicate that N(ε)-(hexanoyl)lysine modification of tropomyosin 1 may be related to neoplastic transformation by N-methyl-N'-nitro-N-nitrosoguanidine in gastric epithelial cells.
    Journal of Clinical Biochemistry and Nutrition 01/2012; 50(1):47-52. · 2.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The O-type forkhead domain transcription factor (FOXO) is involved in many biological processes such as aging, the oxidative stress response, and growth regulation. FOXO activity is tightly controlled within cells. In particular, growth factor signaling pathways and the oxidative stress response can both stimulate nuclear translocation of this transcription factor. Here, we show that tetrahydrocurcumin (THC), a curcumin metabolite, regulates the oxidative stress response and aging via FOXO. In NIH3T3 cells, THC induced nuclear accumulation of FOXO4, a member of the FOXO family of transcription factors, by inhibiting phosphorylation of protein kinase B (PKB)/Akt. In Drosophila melanogaster, THC attenuated the oxidative stress response, an effect that was blocked in a foxo mutant background. THC also extended the life span of Drosophila under normal conditions, and loss of either foxo or Sir2 activity eliminated this effect. Based on these results, THC may regulate the aging process via an evolutionarily conserved signaling pathway that includes both foxo and Sir2.
    Aging 12/2011; 3(11):1098-109. · 4.70 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies have shown that activated neutrophils and their myeloperoxidase (MPO)-derived products play a crucial role in the pathogenesis of non-steroidal anti-inflammatory drug (NSAID)-related small intestinal injury. The aim of the present study is to identify dihalogenated proteins in the small intestine on indomethacin administration. Intestinal damage was induced by subcutaneous administration of indomethacin (10 mg/kg) in male Wistar rats, and the severity of the injury was evaluated by measuring the area of visible ulcerative lesions. Tissue-associated MPO activity was measured in the intestinal mucosa as an index of neutrophil infiltration. The dihalogenated proteins were separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) using novel monoclonal antibodies against dibromotyrosine (DiBrY), and they were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) peptide mass fingerprinting and a Mascot database search. Single administration of indomethacin elicited increased ulcerative area and MPO activity in the small intestine. 2D-PAGE showed an increased level of DiBrY-modified proteins in the indomethacin-induced injured intestinal mucosa and 6 modified proteins were found. Enolase-1 and albumin were found to be DiBrY modified. These proteins may be responsible for the development of neutrophil-associated intestinal injury induced by indomethacin.
    Journal of Clinical Biochemistry and Nutrition 03/2011; 48(2):178-82. · 2.25 Impact Factor
  • Yoji Kato, Toshihiko Osawa
    [Show abstract] [Hide abstract]
    ABSTRACT: Research into lipid peroxidation-induced protein modification has been ongoing for many years. Recent studies on lipo-oxidation shows the occurrence of another type of protein modification, amide-type adduct formation by lipid hydroperoxide, as well as classical aldehyde-derived protein modifications. The amide-type modifications can be either classified as alkylamide and carboxyalkylamide according to the formed structures. As an alkylamide-type adduct, Nepsilon-(hexanoyl)lysine can be formed by the reaction of peroxidized n-6 fatty acid with lysine. Nepsilon-(propanoyl)lysine is considered to be generated from oxidation of n-3 fatty acid with lysine. The generation pattern of both might be useful for classification of which fatty acids are more involved in oxidation in vivo. Since the alkylamide type-adducts are relatively stable and detectable from biological specimens like urine, these adducts, especially Nepsilon-(hexanoyl)lysine, are used as reliable markers for not only oxidative stress evaluation but also development of functional food.
    Archives of Biochemistry and Biophysics 09/2010; 501(2):182-7. · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Myeloperoxidase (MPO) generates reactive halogenating species that can modify DNA. The aim of this study was to investigate the formation of 8-halogenated 2'-deoxyguanosines (8- halo-dGs) during inflammatory events. 8-Bromo-2'-dG (8-BrdG) and 8-chloro-2'-dG (8-CldG) were generated by treatment of MPO with hydrogen peroxide at physiological concentrations of Cl(-) and Br(-). The formation of 8-halo-dGs with other oxidative stress biomarkers in lipopolysaccharide-treated rats was assessed by liquid chromatography tandem mass spectrometry and immunohistochemistry using a novel monoclonal antibody (mAb8B3) to 8-BrdG-conjugated keyhole limpet hemocyanin. The antibody recognized both 8-BrdG and 8-CldG. In the liver of lipopolysaccharide-treated rats, immunostaining for 8-halo-dGs, halogenated tyrosines, and MPO were increased at 8 h, whereas those of 8-oxo-2'-dG (8-OxodG) and 3-nitrotyrosine were increased at 24 h. Urinary excretion of both 8-CldG and 8-BrdG was also observed earlier than those of 8-OxodG and modified tyrosines (3-nitrotyrosine, 3-chlorotyrosine, and 3- bromotyrosine). Moreover, the levels of the 8-halo-dGs in urine from human diabetic patients were 8-fold higher than in healthy subjects (n = 10, healthy and diabetic, p < 0.0001), whereas there was a moderate difference in 8-OxodG between the two groups (p < 0.001). Interestingly, positive mAb8B3 antibody staining was observed in liver tissue from hepatocellular carcinoma patients but not in liver tissue from human cirrhosis patients. These data suggest that 8-halo-dGs may be potential biomarkers of early inflammation.
    Journal of Biological Chemistry 03/2010; 285(12):9282-91. · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Myeloperoxidase (MPO) generates reactive halogenating species that can modify DNA. The aim of this study was to investigate the formation of 8-halogenated 2′-deoxyguanosines (8- halo-dGs) during inflammatory events. 8-Bromo-2′-dG (8-BrdG) and 8-chloro-2′-dG (8-CldG) were generated by treatment of MPO with hydrogen peroxide at physiological concentrations of Cl− and Br−. The formation of 8-halo-dGs with other oxidative stress biomarkers in lipopolysaccharide-treated rats was assessed by liquid chromatography tandem mass spectrometry and immunohistochemistry using a novel monoclonal antibody (mAb8B3) to 8-BrdG-conjugated keyhole limpet hemocyanin. The antibody recognized both 8-BrdG and 8-CldG. In the liver of lipopolysaccharide-treated rats, immunostaining for 8-halo-dGs, halogenated tyrosines, and MPO were increased at 8 h, whereas those of 8-oxo-2′-dG (8-OxodG) and 3-nitrotyrosine were increased at 24 h. Urinary excretion of both 8-CldG and 8-BrdG was also observed earlier than those of 8-OxodG and modified tyrosines (3-nitrotyrosine, 3-chlorotyrosine, and 3- bromotyrosine). Moreover, the levels of the 8-halo-dGs in urine from human diabetic patients were 8-fold higher than in healthy subjects (n = 10, healthy and diabetic, p < 0.0001), whereas there was a moderate difference in 8-OxodG between the two groups (p < 0.001). Interestingly, positive mAb8B3 antibody staining was observed in liver tissue from hepatocellular carcinoma patients but not in liver tissue from human cirrhosis patients. These data suggest that 8-halo-dGs may be potential biomarkers of early inflammation.
    Journal of Biological Chemistry 03/2010; 285(12):9282-9291. · 4.65 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In a previous study we prepared monoclonal antibody against allyl isothiocyanate (AITC)-modified lysine (Lys), and found that AITC reacted with Lys under physiological conditions in vitro (T. Nakamura et al., Chem. Res. Toxicol., 22, 536-542 (2009)). In the present study, antibodies against benzyl isothiocyanate (ITC), 6-methylsulfinylhexyl ITC and phenethyl ITC modified protein were prepared, and the respective monoclonal antibodies, B6C9, 6MS3D10, and PE3A10 were obtained. These antibodies were applied to ITC detection in food using shredded Wasabia japonica (wasabi) and ground Carica papaya (papaya) seed by trapping ITC with biotin-labeled bovine serum albumin. ITC formation from the wasabi and papaya seed samples was confirmed using the antibodies in a dose-dependent manner. These antibodies might be applicable in identifying food-derived ITC.
    Bioscience Biotechnology and Biochemistry 03/2010; 74(3):536-40. · 1.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Lipid peroxidation products have a high reactivity against the primary amino groups of biomolecules such as aminophospholipids, proteins, and DNA. Until now, many papers have reported about the modification of biomolecules derived from lipid peroxides. Our group has also reported that aminophospholipids, such as phosphatidylethanolamine (PE), can be modified by lipid peroxidation including 13-hydroperoxyoctadecadienoic acid (13-HPODE). The aim of this study was to examine the oxidative stress in vivo by detecting the formation of N-(hexanoyl)phosphatidylethanolamine (HEPE) and N-(hexanoyl)phosphatidylserine (HEPS), a novel hexanoyl adduct, using a liquid chromatography/tandem mass spectrometry (LC/MS/MS) and a monoclonal antibody. Consequently, we observed that the formation of HEPE and HEPS occurred in the red blood cell (RBC) ghosts modified by 13-HPODE and the oxidative stress model induced by carbon tetrachloride (CCl(4)) using LC/MS/MS monitoring hexanoyl ethanolamine (HEEA), a head group of HEPE, and hexanoyl serine (HESE) as a part of HEPS. Furthermore, we obtained a novel type of monoclonal antibody against HEPE. This antibody could recognize HEPE in the liver of rats with oxidative stress in vivo.
    Biochemical and Biophysical Research Communications 02/2010; 393(4):631-6. · 2.28 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The expression of cell adhesion molecules (CAMs) has been implicated as one of the most important causes of the development of inflammatory diseases such as atherosclerosis, and, it is speculated that the prevention of it is an effective approach to the control of atherosclerosis. In the present study, we investigated the effect of sesame lignans on the expression of CAMs in human umbilical vein endothelial cells (HUVECs) induced by tumor necrosis factor-alpha (TNF-alpha). Based on cell-ELISA analysis, we found that sesaminol-6-catechol downregulated the TNF-alpha-induced expression of CAMs in a dose-dependent manner. Moreover, these inhibitory effects were caused to be drastically exerted by downregulating the CAM proteins in TNF-alpha-activated HUVECs at transcriptional level. This suggests, that sesaminol-6-catehcol suppresses the expression of CAMs, and may be an active component of sesame lignans.
    Bioscience Biotechnology and Biochemistry 01/2010; 74(8):1539-44. · 1.27 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Daidzein and genistein are the main aglycones of soy isoflavonoid, and have many useful activities in vitro and in vivo. However, equol, a metabolite of daidzein in vivo, has attracted attention due to its stronger activity than that of the naturally occurring isoflavonoids. We subjected the soy isoflavonoids, including the naturally occurring (S)-equol, to mouse adipocytes, and compared the inhibitory activity on the leptin secretion. Equol, daidzein and genistein inhibited the leptin secretion, whereas O-desmethylangolensin had a lower activity. The inhibitory activity of the isoflavones was not affected by the addition of an iNOS inhibitor and an estrogen.
    Phytochemistry Letters - PHYTOCHEM LETT. 01/2010; 3(3):122-125.
  • Food Science and Technology Research 01/2010; 16(5):493-498. · 0.47 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Flavoglaucin, its derivatives, and pyranonigrins, which are antioxidants produced by the molds used in fermented foods, were examined for their inhibition of tumor promotion by the Epstein-Barr virus early antigen activation test. Flavoglaucin and its derivatives exhibited high activity. Flavoglaucin and such a derivative as isodihydroauroglaucin inhibited mouse skin tumor promotion in a two-stage carcinogenesis test and appear to be antitumor promoters.
    Bioscience Biotechnology and Biochemistry 01/2010; 74(5):1120-2. · 1.27 Impact Factor
  • Toshio Niwa, Umeyuki Doi, Toshihiko Osawa
    ChemInform 01/2010; 33(30).
  • Free Radical Biology and Medicine - FREE RADICAL BIOL MED. 01/2010; 49.

Publication Stats

8k Citations
742.68 Total Impact Points

Institutions

  • 2008–2012
    • Kyoto Prefectural University of Medicine
      • • Division of Gastroenterology and Hepatology
      • • Graduate School of Medical Science
      Kyoto, Kyoto-fu, Japan
  • 2009–2011
    • Aichi Gakuin University
      • • Department of Nutritional Science
      • • Faculty of Psychological and Physical Science
      Nagoya-shi, Aichi-ken, Japan
  • 2005–2010
    • University of Hyogo
      • School of Human Science and Environment
      Akō, Hyogo-ken, Japan
    • Miyagi University
      Japan
  • 1988–2010
    • Nagoya University
      • • Graduate School of Bio-Agricultural Sciences
      • • Department of Biological Science
      Nagoya-shi, Aichi-ken, Japan
  • 1999–2008
    • Sugiyama Jogakuen University
      Nagoya, Aichi, Japan
  • 2007
    • National Heart, Lung, and Blood Institute
      Maryland, United States
  • 2004–2007
    • National Center for Geriatrics and Gerontology
      • • Department of Geriatric Medicine
      • • Department of Mechanism of Aging
      Ōbu, Aichi-ken, Japan
    • Hiroshima Prefectural Technology Research Institute
      Hirosima, Hiroshima, Japan
  • 2002–2007
    • Tokai Gakuen University
      Japan
  • 2003–2006
    • Takasaki University of Health and Welfare
      Takasaki, Gunma Prefecture, Japan
    • Doshisha University
      Kioto, Kyōto, Japan
  • 1998–2003
    • Himeji Institute of Technology
      • School of Humanities for Environmental Policy and Technology
      Himezi, Hyōgo, Japan
    • Japan Food Research Laboratories
      Ōsaka, Ōsaka, Japan
  • 1996–2001
    • Kyoto University
      • • Division of Applied Life Sciences
      • • Graduate School of Medicine / Faculty of Medicine
      • • Department of Dermatology
      Kioto, Kyōto, Japan
  • 2000
    • Ochanomizu University
      Tōkyō, Japan
    • National Institute of Health Sciences, Japan
      Edo, Tōkyō, Japan
    • Kobe University
      • Division of Dermatology
      Kōbe, Hyōgo, Japan
  • 1996–1998
    • Aichi University of Education
      • Faculty of Education
      Kariya, Aichi-ken, Japan
  • 1993–1996
    • University of Shizuoka
      • School of Food and Nutritional Sciences
      Shizuoka-shi, Shizuoka-ken, Japan
  • 1991
    • University of California, Davis
      • Department of Environmental Toxicology
      Davis, CA, United States