Protective effects of dissolved molecular hydrogen against hydrogen peroxide-, hydroperoxide-, and glyoxal-induced injuries to human skin keratinocytes

Resveratrol polysaccharide is less cytotoxicity and inhibits UVA-, UVB-, and tertiary-butyl hydroperoxide-induced injury in human keratinocytes

Natural stilbene compounds, such as resveratrol and pterostilbene, have been focused on owing to their diverse biological activities associated with antioxidant, anti-inflammatory, and anti-aging properties. However, their low water solubility limits their advanced applications. In this study, we investigated the protective effects of selected stilbene compounds (resveratrol, oxyresveratrol, gnetol, piceatannol, and pterostilbene) and their water-soluble derivatives (piceid, resveratrol polysaccharide, pterostilbene trisaccharide, and pterostilbene polysaccharide) against UVA-, UVB irradiation, tertiary-butyl hydroperoxide (t-BuOOH)- and hydrogen peroxide (H2O2)-induced injury in human epidermal cells. Our results revealed the significantly greater cytoprotective effects of resveratrol polysaccharide against UVA-, UVB-, and t-BuOOH-induced injury compared to that recorded for other stilbenes. This effect was associated with the suppression of stress-induced intracellular reactive oxygen species (ROS) generation and lipid peroxidation; resveratrol polysaccharides were more effective than other antioxidants. However, the tested compounds could not inhibit H2O2-induced cell injury. Our results indicate that most stilbene derivatives can inhibit UV- and lipid hydroperoxide-induced cellular injury; moreover, resveratrol polysaccharide exhibits excellent protective effects through the suppression of ROS generation and lipid peroxidation. Overall, the poly-glycosylation of resveratrol enhances its effectiveness against UVA or UVB irradiation- and lipid peroxidation-induced injuries in human keratinocytes. Therefore, the resveratrol polysaccharide is proposed to be a novel effective cytoprotective candidate to be used as a cosmetic ingredient for protecting skin from stress-related damage.

High dose of ascorbic acid induces selective cell growth inhibition and cell death in human gastric signet-ring cell carcinoma-derived NUGC-4 cells

Anticancer effects of high-dose vitamin C (VC) have been evaluated on many cancer cell lines, and its efficacy in clinical trials and in combination with anticancer drugs or radiation have been reported; however, its effect on gastric cancer and its mechanisms remain unclear. In the present study, the cell growth inhibitory/lethal effects of high-dose ascorbic acid (AsA), a reduced form of VC was examined on three gastric cancer cell lines. Of these, signet ring cell carcinoma NUGC-4 cells were the most sensitive, but the effects were small and limited in normal cells. Second, high-dose AsA was effective in NUGC-4 cells, whereas dehydroascorbic acid, an oxidized form of VC, was less effective. Third, high-dose AsA showed stronger cell growth inhibitory/lethal effects on floating cells than on adherent cells, and was effective even under hypoxic microenvironment conditions. A single 1-h treatment of high-dose AsA strongly inhibited cell growth, causing apoptosis-like cell death over 72 h after treatment, triggered by hydrogen peroxide generation, actin abnormality, DNA synthesis suppression, DNA damage induction, and ATP level decrease. The effects of high-dose AsA were inhibited either by adding or chelating iron ions, but was not affected via inhibiting AsA transport. Inhibition of glutathione synthesis enhanced the anticancer effects of high-dose AsA. These results indicate that a single high-dose of AsA induces cancer cell-selective, sustained cell growth inhibition and cell death, and these effects may be regulated by iron ion and/or intracellular oxidative stress levels in human gastric signet-ring cell carcinoma-derived NUGC-4 cells.

Molecular Hydrogen Reduces Electromagnetic Pulse-Induced Male Rat Reproductive System Damage in a Rodent Model

Infertility has got to be a broadly concerned social issue these days, in which the malefactor cannot be overlooked. Numerous studies have shown that electromagnetic pulse (EMP) radiation may have seriously damaging effects on reproductive health, through nonthermal effects and oxidative stress. Molecular hydrogen, a selective hydroxyl radical scavenger, explains the protective effects against many diseases closely associated with oxidative damage, such as ionizing radiation (IR). We sought to characterize the beneficial effects of molecular hydrogen on the male reproductive system in a rodent EMP exposure model. The 8-week-old male Sprague-Dawley rats were exposed to EMP (peak intensity 1000 kV/m, pulse edge 20 ns, pulse width 200 ns, 1 Hz, and 200 pulses), with or without hydrogen-rich water. The pathological structure of the testis, the rate of apoptosis of the testis, the serum testosterone level, the sperm parameters, and the activity of the antioxidant enzymes of the testis were measured. Then, transcriptomic and untargeted metabolomic analyses were applied to uncover the underlying mechanism. Exposure to EMP increased testicular apoptosis rate and apoptosis protein level, decreased sperm viability and motility, decreased serum testosterone levels, and diminished testicular antioxidant capacity. Molecular hydrogen-alleviated damage decreased the testicular apoptosis rate and apoptosis protein level, increased sperm motility, increased serum testosterone levels, and improved antioxidative capacity. Omics results showed that molecular hydrogen has a strong influence on metabolic pathways, and EMP affects mainly oxidative phosphorylation, TNF signaling pathways, and cytokine-receptor interactions. The mechanism of molecular hydrogen's effect may be related to the reversal of some metabolite levels. These observations warrant molecular hydrogen as an innovative approach for potential protection against EMP.

Molecular hydrogen suppresses Porphyromonas gingivalis lipopolysaccharide-induced increases in interleukin-1 alpha and interleukin-6 secretion in human gingival cells

Periodontitis is defined as a multifactorial polymicrobial infection accompanied by inflammatory reactions. Porphyromonas gingivalis (Pg) is known as a major pathogen in the initiation and progression of periodontitis, and a major virulence factor is Pg lipopolysaccharide (LPS). Molecular hydrogen (H₂) has been reported to act as a gaseous antioxidant, which suppresses periodontitis progression by decreasing gingival oxidative stress. However, no human periodontitis model has examined the anti-inflammatory effects of H₂. In this study, we examined the effects of H₂ on Pg LPS-induced secretion of 8 types of inflammation markers in a human periodontitis model using human gingival cells with enzyme-linked immunosorbent assays. Our results demonstrated that Pg LPS increased interleukin (IL) 1 alpha (IL-1α) and IL-6 secretion, but H₂ significantly suppressed the secretion of both cytokines without cytotoxicity. H₂ can suppress the production of IL-1α and IL-6, which are identified as cytokines involved in inflammatory reactions in periodontal disease. Thus, H₂ may provide therapeutic applications for periodontitis.