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Journal Articles

Spin-trapping reactions of a novel gauchetype radical trapper G-CYPMPO

Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Kamibayashi, Masato*; Yamashita, Masayuki*; Anzai, Kazunori*; Katsumura, Yosuke*

Analytical Chemistry, 83(24), p.9600 - 9604, 2011/10

 Times Cited Count:23 Percentile:32.31(Chemistry, Analytical)

Chemical reactions of a novel gauche-type spin trap, G-CYPMPO ($textit{sc}$-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphinan-2-yl)-5-methy-1-pyrroline 1-oxide, torsion angle: O1-P1-C6-N1 of 52.8$$^{circ}$$), with reactive oxygen species were examined by pulse radiolysis technique with 35 MeV electron beam and electron spin resonance spectroscopy after $$^{60}$$Co $$gamma$$-ray irradiation. The spin trapping reaction rate constants of G-CYPMPO toward hydroxyl radical and hydrated electron were estimated to be (4.2$$pm$$0.1)$$times$$10$$^{9}$$ and (11.8$$pm$$0.2)$$times$$10$$^{9}$$ M$$^{-1}$$s$$^{-1}$$, respectively. Half-lives of spin adducts, hydroxyl radical and perhydroxyl radical adducted G-CYPMPO were estimated to be $$sim$$35 and $$sim$$90 min, respectively. A comparison of the results with earlier reports using different radical sources suggests that the purity of the solution and/or the radical generation technique may influence the stability of spin adducts.

Oral presentation

Reactivity of a spin trapping agent, CYPMPO, toward water decomposition radicals

Midorikawa, Masamichi*; Yamashita, Shinichi; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Maeyama, Takuya*; Funtowiez, D.*; Kamibayashi, Masato*; Anzai, Kazunori*

no journal, , 

no abstracts in English

Oral presentation

Detection and quantification of the spin adduct produced from CYPMPO and water decomposition radicals

Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke

no journal, , 

Detection and quantification of the oxidative radicals such as hydroxyl radical or superoxide anion radical are very important to clarify the biological oxidative damages. These oxidative radicals, produced by water decomposition with $$gamma$$-ray irradiation, were detected as spin adducts of CYPMPO and themselves. In this work, reactivity CYPMPO and behavior of spin adducts were investigated.

Oral presentation

Detection of the spin adduct produced from CYPMPO and water decomposition radicals

Oka, Toshitaka; Yamashita, Shinichi; Midorikawa, Masamichi*; Saiki, Seiichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke

no journal, , 

The oxygen radicals play a crucial role in biological oxidative damage. It is important to clarify behavior of hydroxyl and superoxide radicals, detection and quantification of these radicals are required. In present work, the reactivities of CYPMPO toward a hydrated electron and a hydroxyl radical utilizing a pulse radiolysis system are investigated, and compared with DMPO (5,5-Dimethyl-1-pyrroline N-oxide) results. The oxygen radicals produced by $$gamma$$-ray irradiation are also discussed.

Oral presentation

Measurement of the reactivity of a novel spin-trapping agent, CYPMPO, by pulse radiolysis study

Midorikawa, Masamichi*; Oka, Toshitaka; Yamashita, Shinichi; Muroya, Yusa*; Lin, M.; Kamibayashi, Masato*; Anzai, Kazunori*; Kudo, Hisaaki*; Katsumura, Yosuke

no journal, , 

5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1pyrroline N-oxide (CYPMPO) is a recently developed spin-trapping agent, which is expected to distinguish O$$_{2}^{- cdot}$$ from $$^{cdot}$$OH. We have determined its reactivity with water decomposed radicals, especially with $$^{cdot}$$OH and with e$$^{-}_{rm{aq}}$$ by pulse radiolysis, and compared results with commonly-used spin trapping agent, 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Furthermore, the reactions with oxidative radicals such as $$^{cdot}$$COO$$^{-}$$, NO$$_{2}^{cdot}$$ and Br$$_{2}^{- cdot}$$ have also been investigated.

Oral presentation

Trapping of the water decomposed radicals by spin-trap CYPMPO, 1

Delamea, N.*; Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Midorikawa, Masamichi*; Katsumura, Yosuke; Kamibayashi, Masato*; Anzai, Kazunori*

no journal, , 

In order to measure the transient radicals quantitatively, the spin trapping technique with a newly developed CYPMPO in 2006 has been applied to detect the water decomposition and secondary radicals using by ESR (Electron Spin Resonance) spectroscopy. We have succeeded to identify five radicals assigned to the spin adducts of $$^{bullet}$$OH, O$$_{2}^{bullet -}$$, HO$$_{2}^{bullet}$$, $${}^{bullet}$$COO$$^{-}$$ and H$$^{bullet}$$.

Oral presentation

Trapping of the water decomposed radicals by spin-trap CYPMPO, 2

Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Midorikawa, Masamichi*; Delamea, N.*; Katsumura, Yosuke; Kamibayashi, Masato*; Anzai, Kazunori*

no journal, , 

A novel spin-trap CYPMPO (5-(2,2-dimethyl-1,3-propoxy cyclophos-phoryl)-5-methyl-1-pyrroline N-oxide) was applied to detect the water decomposed radicals using by ESR (Electron Spin Resonance) spectroscopy, and their lifetimes were estimated.

Oral presentation

Detection of water decomposed radicals produced by $$gamma$$-ray irradiation using a spin-trap CYPMPO

Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Yokoya, Akinari; Katsumura, Yosuke*; Kamibayashi, Masato*

no journal, , 

no abstracts in English

Oral presentation

Detection and stability evaluation of spin adducts of CYPMPO with water decomposition radicals

Oka, Toshitaka; Yamashita, Shinichi; Saiki, Seiichi; Yokoya, Akinari; Katsumura, Yosuke*; Kamibayashi, Masato*

no journal, , 

The reactive oxygen species play crucial roles in biological oxidative damage. In order to clarify the behaviour of hydroxyl and superoxide radicals closely related to the indirect effect of radiation damage of living body and DNA, detection and quantification of these radicals are essential. These radicals are easily produced by radiolysis of water but short lived. In the previous work we reported the rate constants of the reaction of a novel spin trap CYPMPO (5-(2,2-dimethyl-1,3-propoxy cyclophosphoryl)-5-methyl-1-pyrroline N-oxide) towards water decomposed species, e$$^{-}_{mathrm{aq}}$$ and $$^{bullet}$$OH In the present study we have detected these radicals as spin adducts of CYPMPO by ESR and stability of these spin adducts, especially under the acid condition, have been evaluated.

Oral presentation

Detection and stability evaluation of water decomposition radicals using CYPMPO

Oka, Toshitaka; Yamashita, Shinichi; Yokoya, Akinari; Katsumura, Yosuke*; Kamibayashi, Masato*

no journal, , 

no abstracts in English

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