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Potent radical-scavenging activities of thiamin and thiamin diphosphate.

Okai Y, Higashi-Okai K, F Sato E, Konaka R, Inoue M - J Clin Biochem Nutr (2007)

Bottom Line: Various radical-scavenging activities of thiamin and thiamin diphosphate (TDP) were found in some in vitro experiments.In contrast, they caused weak but significantly suppressive effects on the hydroxyl radical generation by Fenton reaction which was measured by electric spin resonance (ESR) method, their IC(50) values were calculated to be 8.45 and 1.46 mM respectively.These results strongly suggest a possibility that thiamin and TDP play as radical scavengers in cell-free and cellular systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Life Science, Osaka Kun-Ei Women’s College, Sets city, Osaka 566-8501, Japan.

ABSTRACT
Various radical-scavenging activities of thiamin and thiamin diphosphate (TDP) were found in some in vitro experiments. Thiamin and TDP caused considerable suppressive effects on superoxide generation in hypoxanthine and xanthine oxidase system which was measured by a sensitive chemiluminescence method using 2-methyl-6-[p-methylphenyl]-3,7-dihydroimidazo[1,2-alpha]pyrazin-3-one (MCLA), and their 50% inhibition (IC(50)) values were estimated to be 158 and 56 microM, respectively. They also showed the significant suppression against hydroperoxide generation derived from oxidized linoleic acid which was estimated by aluminum chloride method and their IC(50) values were calculated to be 260 and 46 microM. They further prevented the oxygen radical generation in opsonized zymosan-stimulated human blood neutrophils which was shown by chemiluminescence method using luminol, and their IC(50) values were calculated to be 169 and 38 microM. In contrast, they caused weak but significantly suppressive effects on the hydroxyl radical generation by Fenton reaction which was measured by electric spin resonance (ESR) method, their IC(50) values were calculated to be 8.45 and 1.46 mM respectively. These results strongly suggest a possibility that thiamin and TDP play as radical scavengers in cell-free and cellular systems.

No MeSH data available.


Related in: MedlinePlus

Typical ESR data of effects of thiamin and TDP on Fenton reaction. (a) positive control experiment of Fenton reaction using ferrous ion and hydrogen peroxide as explained in Materials and Methods. (b) Effect of 10 mM thiamin on Fenton reaction. (c) Effect of 10 mM TDP on Fenton reaction. MnO shows the position of manganese oxide as an internal standard marker.
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Figure 3: Typical ESR data of effects of thiamin and TDP on Fenton reaction. (a) positive control experiment of Fenton reaction using ferrous ion and hydrogen peroxide as explained in Materials and Methods. (b) Effect of 10 mM thiamin on Fenton reaction. (c) Effect of 10 mM TDP on Fenton reaction. MnO shows the position of manganese oxide as an internal standard marker.

Mentions: Hydroxyl radical generated by Fenton reaction was measured by ESR method using electron signal-trapping reagent DMPO. As a positive control experiment, the strong signals of typical ESR spectra for hydroxyl radical were observed in the presence of ferrous ion and hydrogen peroxide compared with the signal of manganese ion as an internal standard marker and 10 mM thiamin and TDP showed the strong suppression on the expression of ESR signals (Fig. 3). As a typical data, 10 mM thiamin and TDP showed the strong suppression on the expression of ESR signals (Fig. 3). As shown in Table 1, when pretreated with different concentrations of thiamin or TDP before the generation of hydroxyl radical, a dose-dependent suppressive effect on hydroxyl radical generation in Fenton reaction was observed from 10 mM to 1 mM, which was shown as the relative signal intensity of hydroxyl radical. However, lower concentrations (20 and 100 µM) of these vitamins caused apparently suppressive effects, but not statistically significant effects. TDP showed much stronger suppressive effect than thiamin, and IC50 values of thiamin and TDP were calculated to be 8.45 and 1.46 mM, respectively. This result indicates that hydroxyl radical-scavenging effects of thiamin and TDP are relatively weak compared with their effects in other assays of our present study.


Potent radical-scavenging activities of thiamin and thiamin diphosphate.

Okai Y, Higashi-Okai K, F Sato E, Konaka R, Inoue M - J Clin Biochem Nutr (2007)

Typical ESR data of effects of thiamin and TDP on Fenton reaction. (a) positive control experiment of Fenton reaction using ferrous ion and hydrogen peroxide as explained in Materials and Methods. (b) Effect of 10 mM thiamin on Fenton reaction. (c) Effect of 10 mM TDP on Fenton reaction. MnO shows the position of manganese oxide as an internal standard marker.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2291503&req=5

Figure 3: Typical ESR data of effects of thiamin and TDP on Fenton reaction. (a) positive control experiment of Fenton reaction using ferrous ion and hydrogen peroxide as explained in Materials and Methods. (b) Effect of 10 mM thiamin on Fenton reaction. (c) Effect of 10 mM TDP on Fenton reaction. MnO shows the position of manganese oxide as an internal standard marker.
Mentions: Hydroxyl radical generated by Fenton reaction was measured by ESR method using electron signal-trapping reagent DMPO. As a positive control experiment, the strong signals of typical ESR spectra for hydroxyl radical were observed in the presence of ferrous ion and hydrogen peroxide compared with the signal of manganese ion as an internal standard marker and 10 mM thiamin and TDP showed the strong suppression on the expression of ESR signals (Fig. 3). As a typical data, 10 mM thiamin and TDP showed the strong suppression on the expression of ESR signals (Fig. 3). As shown in Table 1, when pretreated with different concentrations of thiamin or TDP before the generation of hydroxyl radical, a dose-dependent suppressive effect on hydroxyl radical generation in Fenton reaction was observed from 10 mM to 1 mM, which was shown as the relative signal intensity of hydroxyl radical. However, lower concentrations (20 and 100 µM) of these vitamins caused apparently suppressive effects, but not statistically significant effects. TDP showed much stronger suppressive effect than thiamin, and IC50 values of thiamin and TDP were calculated to be 8.45 and 1.46 mM, respectively. This result indicates that hydroxyl radical-scavenging effects of thiamin and TDP are relatively weak compared with their effects in other assays of our present study.

Bottom Line: Various radical-scavenging activities of thiamin and thiamin diphosphate (TDP) were found in some in vitro experiments.In contrast, they caused weak but significantly suppressive effects on the hydroxyl radical generation by Fenton reaction which was measured by electric spin resonance (ESR) method, their IC(50) values were calculated to be 8.45 and 1.46 mM respectively.These results strongly suggest a possibility that thiamin and TDP play as radical scavengers in cell-free and cellular systems.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Life Science, Osaka Kun-Ei Women’s College, Sets city, Osaka 566-8501, Japan.

ABSTRACT
Various radical-scavenging activities of thiamin and thiamin diphosphate (TDP) were found in some in vitro experiments. Thiamin and TDP caused considerable suppressive effects on superoxide generation in hypoxanthine and xanthine oxidase system which was measured by a sensitive chemiluminescence method using 2-methyl-6-[p-methylphenyl]-3,7-dihydroimidazo[1,2-alpha]pyrazin-3-one (MCLA), and their 50% inhibition (IC(50)) values were estimated to be 158 and 56 microM, respectively. They also showed the significant suppression against hydroperoxide generation derived from oxidized linoleic acid which was estimated by aluminum chloride method and their IC(50) values were calculated to be 260 and 46 microM. They further prevented the oxygen radical generation in opsonized zymosan-stimulated human blood neutrophils which was shown by chemiluminescence method using luminol, and their IC(50) values were calculated to be 169 and 38 microM. In contrast, they caused weak but significantly suppressive effects on the hydroxyl radical generation by Fenton reaction which was measured by electric spin resonance (ESR) method, their IC(50) values were calculated to be 8.45 and 1.46 mM respectively. These results strongly suggest a possibility that thiamin and TDP play as radical scavengers in cell-free and cellular systems.

No MeSH data available.


Related in: MedlinePlus