title: Topical application of a novel, water-soluble gamma-tocopherol derivative prevents UV-induced skin damage in mice.
abstract: We investigated whether the topical application of a novel, water-soluble gamma-tocopherol (gamma-Toc) derivative, gamma-tocopherol-N,N-dimethylglycinate hydrochloride (gamma-TDMG), could protect against UV-induced skin damage in hairless mice. Topical pre- or post-application of a 5% (93 mM) gamma-TDMG solution in water/propylene glycol/ethanol (2:1:2) significantly prevented sunburn cell formation, lipid peroxidation and edema/inflammation that were induced by exposure to a single dose of UV irradiation of 5 kJ/m2 (290-380 nm, maximum 312 nm). This effect was greater than that seen with two alpha-Toc derivatives, alpha-tocopherol acetate (alpha-TA) and alpha-tocopherol-N,N-dimethylglycinate (alpha-TDMG). When a 5% solution of gamma-TDMG was applied to mouse skin for 1 h, cutaneous gamma-Toc increased by 25-fold after 24 h; levels of cutaneous alpha-Toc increased by only two- and eight-fold in alpha-TDMG and alpha-TA treated skins, respectively. These findings indicated that gamma-TDMG immediately converted to gamma-Toc in the skin and suggest that ability of gamma-TDMG to protect the skin from the damaging effects of irradiation was due to its conversion to gamma-Toc. When a 5% solution of gamma-Toc was applied to mouse skin for 1 h, cutaneous gamma-Toc rapidly increased by 25-fold, but fell to baseline levels by 24 h. In contrast, the concentration of gamma-Toc in skin that was treated with gamma-TDMG similarly increased, but these high levels were maintained after 24 h. These results suggest that gamma-TDMG may be a more effective source of gamma-Toc in skin. Thus, the topical application of gamma-TDMG may be efficacious for the prevention of UV-B-induced skin damage.
authors.affiliation: Kyoritsu University of Pharmacy, Tokyo, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Yasuoka
authors.forename: Jiro
authors.initials: J
authors.lastname: Takata
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Karube
authors.forename: Eiko
authors.initials: E
authors.lastname: Katoh
authors.forename: Toshi
authors.initials: T
authors.lastname: Tsuzuki
authors.forename: Junko
authors.initials: J
authors.lastname: Kizu
authors.forename: Masao
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Shizuko
authors.initials: S
authors.lastname: Kobayashi
mesh_terms: D000287:Administration, Topical; D000818:Animals; D005260:Female; D051379:Mice; D008812:Mice, Hairless; D011877:Radionuclide Imaging; D012867:Skin / Q000528:radiation effects*; D012871:Skin Diseases / Q000000981:diagnostic imaging* / Q000517:prevention & control*; D014466:Ultraviolet Rays; D024504:gamma-Tocopherol / Q000494:pharmacology*
chemical_list: D024504:gamma-Tocopherol