Inhibitions by Hydrogen-Occluding Silica Microcluster to Melanogenesis in Human Pigment Cells and Tyrosinase Reaction

Abstract

We investigated the anti-melanogenetic efficacy of hydrogen-occluding silica microcluster (H2-Silica), which is a silsesquioxane-based compound with hydrogen interstitially embedded in a matrix of caged silica, against melanogenesis in HMV-II human melanoma cells and L-DOPA-tyrosinase reaction [EC1.14.18.1]. HMV-II cells were subjected to oxidative stress by ultraviolet ray-A (UVA) exposure of 3-times of 0.65 J/cm2 summed up to 1.95 J/cm2. After UVA irradiation, HMV-II cells were stimulated to produce melanin by 2.72-fold more abundantly than unirradiated control. When HMV-II cells were treated with H2-Silica of 20 ppm or kojic acid of 28.4 ppm before and after UVA-irradiation, the amount of melanin was repressed to 12.2% or 14.5% as compared to that of UVA-irradiated control, respectively. That is, H2-Silica exhibited a comparable efficacy to the whitening agent kojic acid. The H2-Silica could prevent melanogenesis in HMV-II cells by low-level doses at 1-10 ppm, and cell viability and apoptosis event did not change even by high-level doses at 100-1000 ppm. On the contrary, kojic acid was cytotoxic at the concentration of 14-28 ppm or more. By microscopic observation, H2-Silica suppressed such properties indicative of melanin-rich cells as cellular hypertrophy, cell process formation, and melanogenesis around the outside of nuclei. The enzymatic assay using L-DOPA and mushroom tyrosinase demonstrated that H2-Silica restrained UVA-mediated melanin formation owing to down-regulation of tyrosinase activity, which could be attributed to scavenging of free radicals and inhibition of L-DOPA-to-dopachrome oxidation by hydrogen released from H2-Silica. Thus H2-Silica has a potential to prevent melanin production against UVA and serves as a skin-lightening ingredient for supplements or cosmetics.

Influence of hydrogen-occluding-silica on migration and apoptosis in human esophageal cells in vitro

“…The investigators found that cell viability and apoptosis events were unchanged even at high-level concentrations of 100–1,000 ppm. Our results are consistent with those from the report by Kato et al12…”

“…These results suggest that H 2 -silica has an inhibitory effect on human cancer cells, but that only high concentrations of H 2 -silica result in cytotoxic effects on normal human cells. We previously observed that the autoclaved and dehydrogenated H 2 -silica scarcely showed the antioxidant and cytoprotective effects, assumedly through the mechanical inhibition due to contact between silica microparticles-cells, for human keratinocytes HaCaT, which, furthermore, suffered from a slight inhibition for cell proliferation above the definite dose of H 2 -silica which was seemed to be considerably different from one cell line to another cell line 12. On the other hand, we cannot exclude a possibility for the specific toxicity from silica itself or by the pH change of the medium due to addition of silica.…”

“…Kato et al12 investigated the anti-melanogenic efficacy of H 2 -silica in human melanin-generating pigment cells (HMV-II) that were subjected to oxidative stress by ultraviolet A (UVA) light exposure. After UVA irradiation, HMV-II cells were stimulated to produce melanin 2.72-fold more abundantly than the untreated control cells.…”

Electrolytically generated hydrogen warm water cleanses the keratin-plug-clogged hair-pores and promotes the capillary blood-streams, more markedly than normal warm water does

“…Novel types of antioxidants that are effective and safe are eagerly awaited, and mild antioxidants with strong targeting tendencies have been developed. Purified nanomaterials with antioxidant properties have been developed, including hydrogen water, 4 5 Platinum nanocolloid, 5 H 2 -silica, 4 5 6 and fullerene C60. 7 …”

“… 4 5 Multiple pharmacological effects of hydrogen molecules have been reported including antioxidant activities. 4 5 6 8 9 10 11 Drinking hydrogen water for 72 weeks significantly improved the total Unified Parkinson's Disease Rating Scale (UPDRS) score of Parkinson's disease patients. 12 Han et al 13 reported that hydrogen water inhibited the accumulation of the β-galactosidase, an indicator of aging, in the cytoplasm and abnormal nuclei appearance in murine embryonic fibroblasts.…”