Anti-inflammatory and antitumor action of hydrogen via reactive oxygen species

Abstract

Hydrogen (H2) has advantages that lead it to be used as a novel antioxidant in preventive and therapeutic applications. H2 can permeate into biomembranes, cytosol, mitochondria and nuclei, and can be dissolved in water or saline to produce H2 water or H2-rich saline. H2 selectively reduces oxidants of the detrimental reactive oxygen species (ROS), including hydroxyl radicals (·OH) and peroxynitrite (ONOO-), which serve a causative role in the promotion of tumor cell proliferation, invasion and metastasis, but do not disturb metabolic oxidation-reduction reactions in cell signaling. Compared with traditional antioxidants, H2 is a small molecule that can easily dissipate throughout the body and cells; thus, it may be a safe and effective antioxidant for inflammatory diseases and cancer, since ROS usually initiates tumor progression. Treatment with H2 may involve correction of the oxidative/anti-oxidative imbalance and suppression of inflammatory mediators. Therefore the present review will discuss the anti-inflammatory and anti-tumorigenic action of H2 via ROS.

Keywords: anti-inflammatory; antitumor; hydrogen; reactive oxygen species.

Figures

Figure 1.

Illustration of H2 diffusion in a cell. The majority of hydrophilic compounds cannot reach the cytosol and remain at the membranes, but H2 can rapidly distribute into the cytosol and organelles. H2, hydrogen.

Figure 2.

Impact of key oxidants of H2 in cancer: ·OH and ONOO− are highly reactive to damaged cells, while ·O2, NO· and H2O2 have physiological roles as signaling molecules. H2, hydrogen; OH, hydroxyl radicals; ONOO−, peroxynitrite; ·O2, superoxide anion; NO, nitric oxide; H2O2, H2 peroxide; Cl−, chloride; H2O, water; iNOS, inducible nitric oxide synthase; SOD, superoxide dismutase.