title: Ascorbic acid 2-O-alpha-glucoside-induced redox modulation in human keratinocyte cell line, SCC: mechanisms of photoprotective effect against ultraviolet light B.
abstract: We previously reported that the topical application of ascorbic acid 2-O-alpha-glucoside (AA-2G) suppressed the cutaneous inflammation by ultraviolet irradiation in human and guinea pigs (Miyai et al., Nishinihon J. Dermatol., 58, 439-443 (1996)). In this paper, the effect of AA-2G on the lethal damage induced by ultraviolet B (UVB) was studied using a human keratinocyte cell line, SCC, established from squamous cell carcinoma. The photoprotective effect of AA-2G on cytotoxicity of UVB in SCC cells was dose dependent (0.125-1 mM) and more effective than that of ascorbic acid (AsA) at 1 mM. This protection was completely abolished in the presence of an alpha-glucosidase inhibitor, castanospermine, indicating that release of AsA from this derivative was essential for reduction of the actinic injury. AA-2G significantly suppressed cytotoxicities of hydrogen peroxide and superoxide anion produced by xanthine and xanthine oxidase. AA-2G exhibited a preventive effect against the cytotoxicity produced by tert-butylhydroperoxide, an inducer of lipid peroxidation, in the presence of alpha-tocopherol, but not in the absence of alpha-tocopherol. Cytotoxicity of UVB was also effectively reduced by the combination of AA-2G and alpha-tocopherol. In addition, AA-2G reduced UVB-promoted formation of lipid peroxide and accumulation of lipofuscin, which is known to be a complex of cellular proteins and metabolites of lipid peroxide. These data suggest that AA-2G prevents the acute inflammation induced by UVB irradiation partly through scavenging reactive oxygen species and potentiating the antioxidative activity of alpha-tocopherol.
authors.affiliation: Department of Immunochemistry, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Miyai
authors.forename: M
authors.initials: M
authors.lastname: Yanagida
authors.forename: J
authors.initials: J
authors.lastname: Akiyama
authors.forename: I
authors.initials: I
authors.lastname: Yamamoto
mesh_terms: D001205:Ascorbic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006801:Humans; D015603:Keratinocytes / Q000187:drug effects* / Q000528:radiation effects*; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D008062:Lipofuscin / Q000037:antagonists & inhibitors; D018384:Oxidative Stress / Q000187:drug effects / Q000528:radiation effects; D017382:Reactive Oxygen Species; D014466:Ultraviolet Rays
chemical_list: D016166:Free Radical Scavengers; D008062:Lipofuscin; D017382:Reactive Oxygen Species; C065378:ascorbic acid 2-O-glucoside; D001205:Ascorbic Acid