Solid-state Spin Trapping of the Hydroxyl Radical Formed by Gamma-irradiation in Ice and the Scavenging Effect of Sodium<scp>l</scp>-Ascorbate

Yoshioka, Hisashi; Hasegawa, K.

doi:10.1271/bbb.60.1971

Cited by 11 publications

(7 citation statements)

References 3 publications

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“…In the spectra of Fig. 5b and c, the four-line adsorption pattern with an intensity ratio of 1:2:2:1 and a 1.48 mT hyperfine splitting constant (Table 2) is definitely assignable to DMPO-OH adduct (Finkelstein et al 1980;Yoshioka et al 1996;Robert et al 2002). No DMPO-OH EPR signal was detected in control wood sample.…”

Section: Epr Spectroscopy Resultsmentioning

confidence: 88%

Characterisation of the initial degradation stage of Scots pine (Pinus sylvestris L.) sapwood after attack by brown-rot fungus Coniophora puteana

et al. 2011

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In our study, early period degradation (10 days) of Scots pine (Pinus sylvestris L.) sapwood by the brown-rot fungus Coniophora puteana (Schum.: Fr.) Karst. (BAM Ebw.15) was followed at the wood chemical composition and ultrastructure-level, and highlighted the generation of reactive oxygen species (ROS). An advanced decay period of 50 days was chosen for comparison of the degradation dynamics. Scanning UV microspectrophotometry (UMSP) analyses of lignin distribution in wood cells revealed that the linkages of lignin and polysaccharides were already disrupted in the early period of fungal attack. An increase in the lignin absorption A(280) value from 0.24 (control) to 0.44 in decayed wood was attributed to its oxidative modification which has been proposed to be generated by Fenton reaction derived ROS. The wood weight loss in the initial degradation period was 2%, whilst cellulose and lignin content decreased by 6.7% and 1%, respectively. Lignin methoxyl (-OCH3) content decreased from 15.1% (control) to 14.2% in decayed wood. Diffuse reflectance Fourier-transform infrared (DRIFT) spectroscopy corroborated the moderate loss in the hemicellulose and lignin degradation accompanying degradation. Electron paramagnetic resonance spectra and spin trapping confirmed the generation of ROS, such as hydroxyl radicals (HO∙), in the early wood degradation period. Our results showed that irreversible changes in wood structure started immediately after wood colonisation by fungal hyphae and the results generated here will assist in the understanding of the biochemical mechanisms of wood biodegradation by brown-rot fungi with the ultimate aim of developing novel wood protection methods.

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Section: Epr Spectroscopy Resultsmentioning

confidence: 88%

Characterisation of the initial degradation stage of Scots pine (Pinus sylvestris L.) sapwood after attack by brown-rot fungus Coniophora puteana

et al. 2011

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“…We examined the scavenging ability of EGCg by using solid-state spin trapping. 9) This method can be used in cases in which a long time is required for irradiation, or the lifetime of the spin adduct, DMPO-OH, is not long enough compared with the irradiation time so that the spin adduct disappears at the time of ESR measurement. …”

Section: Resultsmentioning

confidence: 99%

“…The objects of this experiment were, therefore, to examine the degree of DNA scission induced by f3-rays in tritiated water in the presence of a green tea percolate (TP) and its main constituent, ( )-epigallocatechin gallate (EGCg), and to explain the protection mechanism molecularly. In addition, a new ESR spintrapping procedure named solid-state spin trapping 9 ) was applied to examine the OH radical-scavenging ability of EGCg and to elucidate the relationship between the protection against DNA scission and the OR radical-scavenging ability, which has been ascertained in the case of y-irradiation. IO ) …”

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confidence: 99%

“…The intensity extrapolated to zero time had to be proportional to the quantity of DMPO-OH formed in the frozen sample, because DMPO-OR did not decrease in the frozen state. 9 ) The intensity at zero time evaluated from Fig. 6 The G value for the OC form of DNA formation, namely the G value for strand scission of the CC form in the absence or presence of EGCg, was calculated by using the data in Fig.…”

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confidence: 99%

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Beta Ray-induced Scission of DNA in Tritiated Water and Protection by a Green Tea Percolate and (–)-Epigallocatechin Gallate

Kurosaki

Yoshinaga

Saito

et al. 1997

Bioscience, Biotechnology, and Biochemistry

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“…The intensity extrapolated to zero time must be proportional to the quantity of DMPO-OH formed in the frozen sample, because DMPO-OH did not decrease in the frozen state. 6 The intensity of DMPO at zero time evaluated from this figure decreased with increasing EGCg concentration. This means that EGCg showed scavenging ability toward the OH radical generated by 13-irradiation in water.…”

Section: Elsevier Science B V Amsterdammentioning

confidence: 86%

Kinetics of reaction between hydroxyl radical formed by beta-rays in tritiated water and tea catechin: Application of the solid state spin trapping method

Yoshioka

Kurosaki

1999

J Radioanal Nucl Chem

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The aqueous solutions of 5,5-dimethyl-l-pyrroline N-oxide (DMPO) containing various amount of (-)-epigallocatechin gallate (EGCg) were mixed with tritiated water, then frozen and 13-ray irradiated in situ for 90 days at -80 ~ ESR spectra were measured as a function of time after melting the sample at room temperature. The intensity of the hydroxyl (OH) radical adduct, DMPO-OH, was obtained by the extrapolation to zero time. The ratio of the reaction rate constants of the OH radical with EGCg and DMPO, kEGc~/kDMPO, was obtained kinetically. The result was compared with the case of DNA and EGCg in tritiated water, in order to make clear the mechanism of the protection of DNA from the radiation-induced scission with EGCg.

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Solid-state Spin Trapping of the Hydroxyl Radical Formed by Gamma-irradiation in Ice and the Scavenging Effect of Sodiuml-Ascorbate

Cited by 11 publications

References 3 publications

Characterisation of the initial degradation stage of Scots pine (Pinus sylvestris L.) sapwood after attack by brown-rot fungus Coniophora puteana

Characterisation of the initial degradation stage of Scots pine (Pinus sylvestris L.) sapwood after attack by brown-rot fungus Coniophora puteana

Beta Ray-induced Scission of DNA in Tritiated Water and Protection by a Green Tea Percolate and (–)-Epigallocatechin Gallate

Kinetics of reaction between hydroxyl radical formed by beta-rays in tritiated water and tea catechin: Application of the solid state spin trapping method

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