Potapenko A Y, Kyagova A A
Russian State Medical University, Moscow.
Membr Cell Biol. 1998;12(2):269-78.
Psoralens (furocoumarins) are photosensitizers of plant origin. They are used in combination with near-ultraviolet (320-400 nm) light for the treatment of vitiligo, psoriasis, cutaneous T-cell lymphoma (CTCL), alopecia areata, eczema, and other skin diseases. Photobiological effects of psoralens in humans are numerous. They photosensitize erythema, hyperpigmentation, and skin aging, affect immune system, etc. Molecular mechanisms of photochemical reactions of psoralens with substrates are also numerous. The molecular basis and the relationships between different photobiological effects of psoralens remain the subject of discussion. The use of antioxidants is an essential instrument for clearing up these problems as well as for the progress of photochemotherapy. It was found that antioxidants (alpha-tocopherol, butylated hydroxytoluene, etc.) selectively inhibited the photochemical stage of erythema and hyperpigmentation but had no impact on the post-irradiation stages of these processes. Evidently, the basis of these processes is the reaction of psoralen-photosensitized oxidation of unsaturated lipids and the impairment of barrier functions of biomembranes, since the photochemical stage of these reactions is inhibited by the antioxidant. At the same time, antioxidants did not inhibit the therapeutic effect in the cases of psoriasis and CTCL. Thus, antioxidants can be used as a tool for improvement of psoralen photochemotherapy.
补骨脂素（呋喃香豆素）是植物来源的光敏剂。它们与近紫外线（320 - 400纳米）光联合用于治疗白癜风、银屑病、皮肤T细胞淋巴瘤（CTCL）、斑秃、湿疹及其他皮肤病。补骨脂素对人体的光生物学效应众多。它们可使皮肤产生红斑、色素沉着过度和皮肤老化等光敏反应，还会影响免疫系统等。补骨脂素与底物发生光化学反应的分子机制也很多。补骨脂素不同光生物学效应之间的分子基础及相互关系仍是讨论的主题。使用抗氧化剂是解决这些问题以及推动光化学疗法进展的重要手段。研究发现，抗氧化剂（α - 生育酚、丁基化羟基甲苯等）可选择性抑制红斑和色素沉着过度的光化学阶段，但对这些过程的照射后阶段没有影响。显然，这些过程的基础是补骨脂素光敏化的不饱和脂质氧化反应以及生物膜屏障功能的损害，因为这些反应的光化学阶段会被抗氧化剂抑制。同时，抗氧化剂在银屑病和CTCL病例中并未抑制治疗效果。因此，抗氧化剂可作为改善补骨脂素光化学疗法的一种工具。
