Research Article: Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water

Date Published: February 9, 2017

Publisher: Public Library of Science

Author(s): Takeki Hamasaki, Gakuro Harada, Noboru Nakamichi, Shigeru Kabayama, Kiichiro Teruya, Bunshi Fugetsu, Wei Gong, Ichiro Sakata, Sanetaka Shirahata, Nukhet Aykin-Burns.


Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles.

Partial Text

It has been reported that tap water purifier coverage rate reached almost 60% in an urban area of Japan [1]. The higher distribution rate of the purifiers arises from customers’ increasingly higher health-oriented desire to drink purer and safer water, which is free from tap water contaminants such as chlorine and its derivative trihalomethane, hormone-disrupting chemicals, aluminums and rust particles leaching from the inner walls of aged water pipes. Moreover, people are also demanding that these purifying apparatuses positively promote their health. Among the purifiers, alkaline ionized water generators have attracted attention because the produced water is not only tasty but also beneficial to human health. Consequently, 200,000 apparatuses have been sold each year in Japan [2]. An alkaline ionized water generator produces electrolyzed water on the surface of the cathode during electrolysis where produced water is commonly referred to as electrochemically reduced water (ERW) [3]. Typically, apparatuses that produce ERW are composed of two units, a micro-carbon cartridge unit for removal of contaminants and an electrolysis unit that acts on the purified water. Purified tap water passed through a micro-carbon cartridge unit flows into the electrolysis unit, which is composed of five platinum (Pt)-coated electrode plates, separated by semi-permeable membranes and the water is electrolyzed while passing through the gaps between the electrodes [3]. ERW exhibits suppressive effects against oxidative stress, which correlates with DNA protection [4,5], carbon tetrachloride-induced liver damage [6], lifespan extension of Caenorhabditis elegans [7,8], alloxan-induced type 1 diabetes [5,9], hemodialysis-induced oxidative stress during end-stage renal disease [10,11] and lipopolysaccharide-induced neuroinflammation [12].

We verified significant electrolysis intensity-dependent intracellular ROS-scavenging activity of ERW. DPPH and ORAC assays revealed that ERW did not show radical-scavenging activity. ERW had significant reduction of intracellular ROS activity in comparison with H2-dissolved water. Additionally, ERW retained its ROS-scavenging activity even after removal of dissolved H2, but lost its activity when autoclaved. The combined results suggest that ERW contains not only dissolved H2 but also a trace amount of Pt NPs. These Pt NPs may act as a ligand for the activation of intracellular antioxidant systems via hypothetical receptors, which gives rise to an indirect ROS scavenging mechanism in cells.