Molecular hydrogen: biological effects, possibilities of application in health care. Review

Hydrogen (H₂) is the lightest and most common element in the universe. In molecular form, (H₂) is a colorless, odorless, tasteless and non-toxic gas. For a long time, hydrogen was considered physiologically inert until its ability to reduce the intensity of the negative effect of oxidative stress was detected. According to modern concepts, oxidative stress affecting cells and tissue to be damaged, aged and causing a number of diseases - cardiovascular, rheumatic, gastrointestinal, neurodegenerative, oncological, metabolic and other. Antioxidants, however, have had limited use in the prevention and treatment of oxidative stress-related diseases due to the high toxicity and low efficacy of many of them. Therefore, it remained necessary to identify effective antioxidants with little-to-no side effects. Since 2007, discovery molecular hydrogen (H₂) to possess selective antioxidant properties, multiple studies have demonstrated H₂ to show beneficial effects in diverse human disease (such as digestive, cardiovascular, central nervous, respiratory, reproductive, immune, endocrine systems diseases, cancer, metabolic syndrome, and aging). H₂ is a specific scavenger of •OH, which is a very strong oxidant that reacts with nucleic acids, lipids, and proteins, resulting in DNA fragmentation, lipid peroxidation, and protein inactivation. Fortunately, H₂ does not appear to react with other ROS having normal physiological functions in vivo. Due to its mild but effective antioxidant properties, H₂ can reduce oxidative stress and cause numerous effects in cells and tissues, including anti-apoptosis, anti-inflammatory, anti-allergic and metabolic effects. This review discusses H₂ biological effects, describes effective H₂ delivery approaches and summarizes data on the results and prospects of H₂ applications in the prevention of human diseases and therapy.