涉及光疗机制的生物光化学

本文对光生物和光化学的定义,反应机制的类型和光敏化作用等做了阐述。下面例举几个光疗的成果 1.光疗牛皮癣 经常使用的8-甲氧基补骨脂素在UVA的照射下,从基态被激发到三重态。它主要和DNA中的胸腺嘧啶,其次和色氨酸进行光环合加成,形成交联,阻止DNA和RNA的合成,抑制具过度增生 2.血卟啉衍生物(HPD)治癌 HPD有定位于癌组织的能力和光动力作用,可推断病人体内癌部位。 讨论了HPD的光疗机制,和酞菁相比,有各自的优缺点。 3.竹红菌素 主要治疗妇女外阴白色病变和疤痕疙瘩,抑制癌细胞生长。 讨论了竹红菌甲素和乙素及它们的氧化物的结构和活性。 在大于510nm的光照射下,也可抑制癌细胞的生长。列举了竹红菌素的优缺点。

PHOTOBIOLOGY RELATED TO THE MECHANISMS OF REACTIONS OF CERTAIN PHOTOMEDICINES

In this paper, the definitions, the types of reaction mechanisms, and the photosensitizaticns in photobiology and photochemistry are discussed Several phototherapentic examples are given: 1. The Treatment of psoriasis. ( 8 - MOP) The frequently used 8-Methoxypsoralen is irradiated with UVA, its ground stateis excited to the triplet state. The main reaction is the cycloaddition with Thymine base of DNA, and the side reaction is the cycloaddition with tryp-tophane. Crosslinking takes place. This reaction could inhibite the synthesis of DNA or RNA. It could also depress the overgrowth of DNA. 2. The Killing effect of Hematoporphrin derivatives ( HPD ) to-wards cancer cells. IIPD has the ability of orientation of the site of cancer tissue and is used for the deduction of the site of cancer cells in the body of the patient. The phototherapentic mechanism of HPD is discussed. In comparison with pht-halocyanine, each one possesses its own advantages and drawbacks respectively. 3 Hypocrllins Hypocrellin A and B are potent phototherapentic agents. They are applied mainly for the treatment of white lesions of vnlva and keloid. They can also depress the growth of cancer cells. The structures and biological activities of Hypocrellin A and B as well as their oxidized products are discnssed. Under irradiation with>5l0nm light, the growth of cancer cells are inhibited all the same. The advantages and drawbacks of Hypocrellins as photomedicines are listed.