Effects of α-tocopherol on phototoxicity of 8 - methoxypsoralene

Effects of singlet oxygen extinguisher α-tocopherol on combined effects of psoralens and UV on erythema photosensitized with 8-methoxypsoralene were investigated. The leading role of the reactions of photocompounds in induction of PUVA - erythema is considered. A characteristic feature of biologically active psoralens is the high value of quantum output of intercombination conversion, due to which, after absorption of light quants, a significant number of psoralen molecules are formed in a triplet excited state. Psoralen derivatives differ greatly in their ability to photosensitize the skin. In the example of 8-psoralens, a correlation was found between the ability to induce erythema by photocompound to double-spiral DNA in vitro. A clear correlation was identified between the ability to photosensitize erythema and form diadducts. Α-tocopherol has been shown to protect the skin from PUVA erythema if presents during irradiation. In the case of application of α-tocopherol after irradiation, the inhibitory effect was not exhibited.