A Comparison of Scavenging Abilities of Antioxidants against Hydroxyl Radicals

Stimulatory Effects of Hydroxyl Radical Generation by Ga-Al-As Laser Irradiation on Mineralization Ability of Human Dental Pulp Cells

“…Excess production of active oxygen species is considered to result in substances causing various diseases, but recent attention has focused on the fact that differing quantities of production have bactericidal and other bio-defensive roles, as well as enhancing cell-proliferative activity, and information signaling. [16][17][18] Nishida et al have reported 19) that · OH produced from H 2 O 2 play a role in cell signaling by activation of cell membrane G-protein. Lee et al have also reported 20) that H 2 O 2 significantly increases ALP activity and the formation of calcified nodules in MDPC-23 cells.…”

Effects of Alcoholic Solvents on Antiradical Abilities of Protocatechuic Acid and Its Alkyl Esters

“…[1][2][3][4][5][6][7][8][9][10][11] Among them, protocatechuic acid (3,4-dihydroxybenzoic acid) and gallic acid (3,4,5-trihydroxybenzoic acid) are typical molecules which show potent antiradical activity. 1,2,[5][6][7][8]11) We have examined the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging reaction 12,13) of those acids and methyl esters and found that methyl protocatechuate and gallate were converted to their oxidative dimers with different connectivities during reaction in an aprotic solvent.…”

Iron Chlorin e6 Scavenges Hydroxyl Radical and Protects Human Endothelial Cells against Hydrogen Peroxide Toxicity.

“…The rate constant for reaction between DMPO and hydroxyl radical is cited as 3.4ϫ10 9 M Ϫ1 s Ϫ1 in the literature, 36) but DMPO was added at a concentration of 90 mM in our ESR experiments. Consequently, Ce6 at lower concentrations than 100 mM could not compete with DMPO, because the rate constant of Ce6 with hydroxyl radical was 1.3ϫ10 10 M Ϫ1 s Ϫ1 in our experiments, which was only 3.8 times as high as that of DMPO. Especially, the rate constant for reaction between FeCe6 and hydroxyl radical was 8.5ϫ10 10 M Ϫ1 s Ϫ1 , calculated from the amount of TBARS, and this value was much higher than 1-9ϫ10 9 M Ϫ1 s Ϫ1 of various hydroxyl radical scavengers.…”