u Joumal oprplied Electrochemfxlry 31: l307 ‘1313. 2001. 1307 ZOÙI Kluwer Academlc Publtshers. aned In the Nelherlamls. Antioxìdant efl'ects 01’ reduced water produced by electrolysis of sodium chloride solutions K. HANAOKA‘ Bio-REDOX Laboratory 1120., 1187-4 0020- Ueda, Ueda-shi, Nagano 386-0001, Japan (‘faxr +81 268 24 0050) Received 23 December 2000: accepted in revised l'onn 21 August 2001 Key words: antioxidant, dismutation activity, electrolysis, hydrogen peroxide, reduced water, superoxide radicals Abstract Antioxidant vitamins and enzymes such as superoxide dismutase, catalase and glutathione peroxidase are considered to function as scavengers against reactive oxygen species and to provide protection against reactive oxygen species, including free radicals. Although antioxidants such as L-ascorbic acid, d-catechin and quercetin dehydrate show superoxide dismutation activity, using reduced water produced in the cathode side by electrolysis as a solvent instead of 2 mM NaCl solution of the same pH leve] as the reduced water increased the superoxide dismutation activity of these antioxidants. Moreover, neither the reduced water nor its electrolyte solution showed any superoxide dismutation activity by itself. On the other hand, the reduced water was able to decrease hydrogen peroxide levels. It has been found that the behaviour of H2 in reduced water, which was activated by a platinum electrode, difi'ered from that of H2 introduced by bubbling of hydrogen gas. The former decreased 11202, whereas the latter did not. These results suggest strongly that the increase in superoxide dismutation activity, with a proton donor such as L-ascorbic acid, is due to an increase in the dissociation activity of water while the scavenging activity for H20; is due to activated dissolved H2 in the reduced water. l. Introduction out using ethylenediaminetetraacetic acid (EDTA) with a luminescence method. EDTA dissolved in reduced A free radical is any molecule, which contains one or water will produce higher superoxide dismutation ac- more unpaired electrons, and includes superoxide an- tivity by playing the role of a proton donor. As a result, ions (02"), singlet oxygen (’02) hydroxyl radicals (-OH), the phenomenon of superoxide dismutation in reduced hydroperoxyl radicals ('OOH), nitrogen monoxide rad- water seems to occur directly. The reason why this icals (NO') and hydrogen peroxide molecule (11202). phenomenon occurs has been clarified. In these studies, Although it is a reactive oxygen species, the hydrogen superoxide dismutation activity and hydrogen peroxide peroxide molecule does not contain unpaired electrons scavenging activity of reduced water produced by and is not a free radical. electrolysis of electrolyte solutions, and OH’ ions were Reactive oxygen species or free radicals are extremely examined by electron spin resonance, ion chromato- reactive and can cause cell injury or death [l-4]. Under graphy and neutralization titration methods. certain conditions, these reactive oxygen species play a significant role in the disease