A5105675141- Free Radicals and Antioxidants
- Photochemistry and Electron Transfer Studies
- Antioxidant Activity and Oxidative Stress
- Pharmacological Effects of Natural Compounds
- Sulfur Compounds in Biology
- Electrochemical Analysis and Applications
- Natural product bioactivities and synthesis
- Sulfur-Based Synthesis Techniques
- Pharmaceutical and Antibiotic Environmental Impacts
- Nitric Oxide and Endothelin Effects
- Water Treatment and Disinfection
- Pharmacogenetics and Drug Metabolism
- Metal-Catalyzed Oxygenation Mechanisms
- Electron Spin Resonance Studies
- Synthesis and Catalytic Reactions
- Phytochemicals and Antioxidant Activities
- Chemical Synthesis and Reactions
- Analytical Chemistry and Chromatography
- Chemical Reactions and Isotopes
- Phytochemistry and biological activity of medicinal plants
- Biochemical effects in animals
- Vitamin C and Antioxidants Research
- Organic and Inorganic Chemical Reactions
- Ginseng Biological Effects and Applications
- Organic Chemistry Cycloaddition Reactions
Tokyo University of Science
2009-2023
Sanyo-Onoda City University
2023
Sanyo (Japan)
2022
Gifu Kyoritsu University
2008-2017
Kyushu Kyoritsu University
2009-2016
Noda Institute for Scientific Research
2014
The scavenging reaction of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙) or galvinoxyl (GO˙) by a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), was significantly accelerated the presence Mg(ClO4)2 in de-aerated methanol (MeOH). Such an acceleration indicates that radical-scavenging 1H MeOH proceeds via electron transfer from to radical, followed proton transfer, rather than one-step hydrogen atom which has been observed acetonitrile (MeCN). A significant negative shift...
The phenoxyl radical 1˙ of a vitamin E analogue, generated by the reaction 2,2,5,7,8-pentamethylchroman-6-ol (1H) with 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH˙) or galvinoxyl (G˙), was significantly stabilized presence Mg2+. Addition Mg2+ into solution resulted in red shift absorption band as well decrease g value EPR spectrum 1˙, indicating complex formation between and complexation retards disproportionation electronic repulsion metal cation organic (1+), leading to stabilization...
Electron-transfer reduction of molecular oxygen (O2) by the phenolate anion (1-) a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H), occurred to produce superoxide anion, which could be directly detected low-temperature EPR measurement. The rate electron transfer from 1- O2 was relatively slow, since this process is energetically unfavourable. one-electron oxidation potential determined cyclic voltammetric measurements sufficiently negative reduce...
A powdered ethanolic extract of Glycyrrhiza aspera root exhibits antimutagenic activity against N-methyl-N-nitrosourea (MNU) based on the Ames assay with Salmonella typhimurium TA1535. The aim this study was to identify components G. root.The sequentially suspended in n-hexane, carbon tetrachloride, dichloromethane, ethyl acetate, and ethanol, each solvent soluble fraction residue were assayed for MNU S. dichloromethane exhibited highest antimutagenicity fractionated several times by silica...
N-Nitrosodialkylamines, activated metabolically by cytochrome P450, possess mutagenic and carcinogenic activity. In this study, the hydroxyl radical, generated from Fenton's reagent, was used as an oxidant for activation of N-nitrosodialkylamines. Ethyl acetate extract reaction mixture which included Fe2+-Cu2+-H2O2 N-nitrosodialkylamines; N-nitrosodimethylamine (NDM), N-nitrosodiethylamine (NDE), N-nitrosodipropylamine (NDP), N-nitrosodibutylamine (NDB), N-nitroso-N-methylpropylamine (NMP),...
A series of 6-chromanol derivatives were synthesized, and their second order rate constants (<italic>k</italic>) for the reaction with galvinoxyl radical determined. The from slope, which plotted log <italic>k</italic> versus Hammett sigma or Taft four substituents at each, obtained.
Chemical models for cytochrome P450, consisting of an iron porphyrin complex and oxidant, have been used as substitutes the S-9 mix detecting mutagenicity promutagens in Ames assay. In this study, we developed optimized procedures mutation assay using a water-insoluble 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinatoiron(III) chloride (F5P) or water-soluble 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrinatoiron(III) (4-MPy) plus tert-butyl hydroperoxide (t-BuOOH) chemical model to...
Antimutagenesis against N-nitroso compounds contribute to prevention of human cancer. We have found that Glycyrrhiza aspera ethanolic extract exhibits antimutagenic activity N-methyl-N-nitrosourea (MNU) using the Ames assay with Salmonella typhimurium TA1535. In present study, eight purified components from Glycyrrhiza, namely glabridin, glycyrrhetinic acid, glycyrrhizin, licochalcone A, licoricesaponin H2, G2, liquiritigenin and liquiritin were evaluated for their antimutagenicity MNU in S....
The hydroxyl radical-scavenging activity of the amino-substituted α-tocopherol analogues was much higher than that α-tocopherol. Aminochromanoxyl radicals generated from 5- and 7-aminochromanol were successfully detected in aqueous solution at room temperature during ESR measurements. stability aminochromanoxyl leads to a significant enhancement activity.
Benzo[h]chromanols, which possess a tocopherol moiety, have been reported to exhibit potent antioxidant activity.Several benzo[h]chromanols with various substituents (nitro, chloro, bromo, methyl, or amino groups at the position ortho phenolic OH group) were synthesized, and second-order rate constants (k) of their reaction galvinoxyl radical determined.The introduction electron-withdrawing chloro nitro decreased activity, activity correlated well substituent...
Small molecule antioxidants such as ascorbic acid (AscH2) prevent the oxidative damage of biological molecules by scavenging reactive oxygen species.A carbonyl-conjugated ene-diol structure is essential for antioxidant activity AscH2.As such, we synthesized novel AscH2 analogs containing a carbonyl conjugated and evaluated their radical activities.When 1,2-dihydroxyethyl group was removed, equal to observed.Analogs an endocyclic nitrogen atom instead ring displayed higher activities than...
The phenoxyl radical 1*, generated by the reaction of a vitamin E model, 2,2,5,7,8-pentamethylchroman-6-ol (1H) with 2,2-bis(4-tert-octylphenyl)-1-picrylhydrazyl (DOPPH*), was significantly stabilized complex formationwith Mg 2 + in deaerated acetonitrile at 298 K. assignments hyperfine coupling constants (hfc) obtained computer simulations observed EPR spectrum 1* (Mg -1*), were carried out using three deuterated isotopomers i.e., 5-CD 3 -1*, 7-CD and 8-CD where methyl group C5, C7, or C8...