Uptake and bioconversion of alpha-tocopheryl acetate to alpha-tocopherol in skin of hairless mice

The photoprotective effect of topically applied alpha-tocopheryl acetate (vitamin E acetate), a stable derivative of alpha-tocopherol (vitamin E), and its possible bioconversion to the active antioxidant species (alpha-tocopherol) was examined in skin tissue of female hairless mice (HRS/J) exposed to UV-B irradiation. Our results indicate that topically applied alpha-tocopheryl acetate is absorbed into and retained by skin tissue. Furthermore, skin tissue from UV-B-irradiated animals that received daily topical alpha-tocopheryl acetate treatments contained significantly higher levels (P < 0.001) of alpha-tocopheryl acetate than non-UV-B-irradiated mice that received identical daily topical alpha-tocopheryl acetate treatments. Finally, free alpha-tocopherol levels in skin also were significantly increased (P < 0.001) by topical applications of alpha-tocopheryl acetate and skin levels of free alpha-tocopherol were significantly greater (P < 0.001) in UV-B-irradiated animals that received daily topical alpha-tocopheryl acetate treatments than in non-UV-B-irradiated animals. These results suggest that UV-B irradiation enhances both the absorption of alpha-tocopheryl acetate and its bioconversion to free alpha-tocopherol.